Today's Message Index:
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1. 04:16 AM - Re: Re: Why would my Yak 52 m14p lose power? (A. Dennis Savarese)
2. 05:13 AM - Re: Why would my Yak 52 m14p lose power? (N395V)
3. 06:39 AM - Re: Why would my Yak 52 m14p lose power? (KJKimball@aol.com)
4. 08:53 AM - Re: Why would my Yak 52 m14p lose power? (Yak Pilot)
5. 08:58 AM - Re: Re: Why would my Yak 52 m14p lose power? (Yak Pilot)
6. 09:12 AM - Re: Re: Why would my Yak 52 m14p lose power? (nc69666@aol.com)
7. 09:22 AM - Re: Why would my Yak 52 m14p lose power? (nc69666@aol.com)
8. 09:26 AM - Re: Re: Why would my Yak 52 m14p lose power? (A. Dennis Savarese)
9. 10:32 AM - Re: Re: Why would my Yak 52 m14p lose power? (Yak Pilot)
10. 10:45 AM - Re: Re: Why would my Yak 52 m14p lose power? (Eddie Moran)
11. 01:50 PM - Re: Re: Why would my Yak 52 m14p lose power? (Eddie Moran)
12. 02:01 PM - Re: Re: Why would my Yak 52 m14p lose power? (A. Dennis Savarese)
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
I acquired the "fix" from our friend George Coy.
All good input Mark. I also agree one can pull the throttle back until
one can see a slight decrease in MP and save fuel. This is proven by
watching the JPI fuel flow instrument installed in my airplane as well
as others.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 10:01 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
Was not trying to disagree or start an argument with you Dennis .
Just did not believe that this cure was applicable to the problem being
described. Respectfully, I still do not.
Regarding the stumble in throttle movement. I have talked to many
people about this pressure carb. A lot of people think they have this
thing fully figured out and I have some doubts there since their
explanations seem to differ from the mechanics I have talked to that are
Russians themselves and were trained in that country. I know that my
personal understanding is much less than complete to put it mildly. I
do not have the personal first hand experience to back this up, but from
what I have seen one Russian do, it appears that the "P" model engines
that I have seen stumble are usually able to be cured without plugging
the accel pump. Some cases have required changing air bleed jets to
values that "by the book" seemed to be rather extreme, but the change
then allowed the accel pump jet to be pretty much left alone, or
operated withinn normal ranges but never plugged. This is problematic
in that this puts strong suspicion on proper operation of the diaphragms
in that the engine was possibly over rich in the transition range to
begin with. My comment about P vs. PF engines was not meant to imply
that the problem could not happen with a P model, but that in every case
I have seen it could be cured by exercising the complete range of
adjustments possible with this carb, further that while it may have been
tried and used successfully with the P model, that according to my
sources, it was originally intended for the PF model where this problem
happens more often. I am not sure who "invented" this mod.... Seems to
me I was told once... might have been you, George Coy, I really am not
sure. I hope someone chimes in regarding this so that if I am wrong on
that point, I can be corrected. Given that there is no magic in how
an engine burns fuel, and that there are a lot of P models that run
perfectly without the accel jet plugged, it seems to me that an engine
that does not run right has something out of adjustment (or just not
working right internally) and does not need a carb design change. No
question that the mod works on some engines, but to me it is a matter of
robbing Peter to pay Paul.
Bottom line, no one around here has a flow bench for these things that
I know of, or has tried to truly tackle over-hauling one and then
charting the flow curves on this side of the pond, and since the darn
things are no longer in production, long term users may eventually
switch to fuel injection anyway.
While New Bern is not a big airport for Russian engines, we have had 5
aircraft with P model engines, all of which ran perfectly without
stumble, and another 4 with PF models, ALL of which stumble some worse
than others.
I was told that the carb does have a circuit for WOT mixture
enrichment. I was also informed the operator can pull the throttle back
until a very small change in manifold pressure is seen in order to save
fuel with minimum performance loss. Both pieces of info came from
Russian sources directly, if that means anything.
Mark Bitterlich
-------------------------------------------------------------------------
-----
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 7:00:34 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
Mark,
There are many, many M14P's, 360 HP engines that exhibit the throttle
response hesitation. The problem is not limited to the PF engine only.
The problem of throttle response hesitation can be reduced by changing
the accelerator pump jet down to a smaller diameter. The smallest
accelerator pump jet is .9 mm and I can say from experience, changing to
the .9 mm jet does not totally eliminate the problem on those engines
that exhibit the problem.
I too have plugged many an accelerator pump jet to stop the hesitation
problem on both P and PF engines. My opinion is, the accelerator pump
jet provides additional fuel during WOT which helps to cool the
cylinders (richer mixture). I'm not sure what the long term impact
might be by plugging the accelerator pump jet.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 1:42 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
I'll take some flames if necessary, but I feel I must point out that
this mod was actually intended for fixing the throttle lag experienced
in a lot of M-14PF model engines (400HP) and NOT for the M-14P model,
which is the straight 360 HP engine. A normal M-14P engine should run
perfectly WITHOUT needing this modification.
Point number two. Something that has worked normally in the past,
and then suddenly starts working abnormally, or in a way different from
in the past is usually happening because something has changed and not
because something needs to be modified. I think this problem meets that
description.
This particular engine lost power when throttled back. It did not
stumble and falter when the throttle was advanced from idle on the deck.
This does not sound like an accelerator pump issue.... ice possibly,
water in the fuel, low fuel pressure, a tank venting problem, you name
it... lots of possible causes, but I would be very hesitant to recommend
the accel pump mod on ANY engine for the described problem.
Respectfully,
Mark Bitterlich
N50YK.
p.s. Run this by Sergei Boriak, or better yet Vladimir
Yastremski... I think you will find they will agree.
-------------------------------------------------------------------------
---
From: Eddie Moran <eddiemoranii@yahoo.com>
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 11:18:38 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
David, << We're removing a plug to uncover the jet below it.>>
Yes, #10 on the diagram is the plug (11mm) that you pull to get to the
jet.
The jet unscrews, comes out, has a little hole in it. You
plug that somehow..(weld, JB, etc.). Then reinsert the jet and
reinstall the 11mm plug.
My engine ran much better after the mod with no noted lag in
acceleration.
Eddie
--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.ca> wrote:
From: DAVID STROUD <dstroud@storm.ca>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p
lose power?
To: m14pengines-list@matronics.com
Date: Saturday, December 20, 2008, 10:32 AM
I'm slightly confused now. We're removing a plug to uncover
the jet below it. Your last sentence says 'plug it and reinstall' ,
do you mean to
remove the jet, plug it ( the jet ) somehow, then reinstall
the plugged jet and cover it with the first plug? Is this process done
on the Huosai
engine too ? thanks..
David Stroud Ottawa, Canada
Christavia C-FDWS
Fairchild 51 replica
under construction C-FYXV
----- Original Message -----
From: Eddie Moran
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 10:02 AM
Subject: Fw: Re: M14PEngines-List: Why would my Yak 52
m14p lose power?
Mark,
I am not an expert by any means but I agree
on the ice theory. I also have a picture of the accel plug fix. I
would plug that if you have not already. The following info came from
Dennis a few years ago.
See attached. Item #10 is a plug (11 mm I
believe) and under the plug is the acceleration pump jet. The jet has a
slot in it just like a slotted screw. Use a straight blade screwdriver
to remove. Plug it and reinstall.
The figure is attached.
Eddie Moran
N320VT
Murphy Moose
--- On Thu, 12/18/08, markgreenway
<geewhizmark@gmail.com> wrote:
From: markgreenway <geewhizmark@gmail.com>
Subject: M14PEngines-List: Why would my
Yak 52 m14p lose power?
To: m14pengines-list@matronics.com
Date: Thursday, December 18, 2008, 9:30 PM
"markgreenway"<geewhizmark@gmail.com>Hello Guys Any idea why I lost
power and had to make a forced landing ,because whencrossing midfield
for landing, the motor lost power when I throttled back. Itnever totally
died and it regained power once on the ground
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Is not a slight stumble inherent in all radials?
--------
Milt
2003 F1 Rocket
2006 Radial Rocket
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=220504#220504
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
The carb mod was the original idea of Ben Morphew of McKinney Texas in 1990
to stop the stubble the engine has when advancing the throttle. Ben was part
of a group with Dr Tom ?? who brought in several yak 52s and 3 sukhois in
1990. These airplanes all had M14P engines not PF engines since the PF was not
available until the late 90's. So, the talk of it only being a PF issue
cannot be correct. Ben has lots of experience with PS5 pressure carbs on Pitts
airplanes and knew of a mod made on those PS5 carbs. This PS5 mod was done by
Curtis Pitts and the carb OH facility in FL that Curtis used for his 4 cyl
lyc. airplanes since the PS5 was designed for engines of more than 400 cubic
inches. On the PS5, the accelerator pump diaphragm was limited in travel with
a bolt.
In the M14 carb, there is no accelerator pump diaphragm instead having an
over enrichment jet. Ben studied the carb data and determined which jet to
plug up. Ben made the mod on Les Crowder's yak (Ben and Les were neighbors and
friends) as a test of his theory and it worked great! So, they began to do
the mod to other airplanes since Ben and Les were seeing airplanes damaged
with hard landings and taxi problems due to the blubber of the carb. Les did
Yaks and Ben did Sukhois. In 1997, Ben showed me the mod on an engine here and
recommended we do this mod to all the M14 engine we mess with which we have
done. I then created the "how-to" instructions on our website. Again, this
blubber can happen with P engines not just PF and this is shown to be true
based on the history and time line of the carb mod.
Can you solve the throttle stumble in other ways? Sure. Now we know there
are a handful of jets available for this port which can be swapped around you
get better performance but it make take several trials to get it right. The
carb mod is simple to do, takes only minutes and is reversible. Folks in
the non-south can have 2 jets, one plugged for warm and one unplugged for cold
flying as George Coy later pointed out that the mod works great with the
exception of some airplanes operated in extreme cold conditions. The over
enrichment jet helps to keep the very cold engine running at lower power.
As for carb ice on pressure carbs, it is possible and has been shown to have
happen on PS5 carbs and on the M14 carb. I know of a suhkoi that had ice
and the owner was able to see the ice on inspection. I know of a yak 52 in the
northwest that had ice on taxi and warm up to the point it locked the
throttle in position. Once shut down and the engine heat warmed the carb body,
the
ice melted and the throttle operated normally. It can happen in the right
conditions.
Have Fun,
Kevin Kimball
.
**************One site keeps you connected to all your email: AOL Mail,
Gmail, and Yahoo Mail. Try it now.
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Thanks for the really informative reply Kevin, and I stand corrected.- Yo
u really raised my eyebrows when you mentioned Les.- My YAK-50 used to be
owned by Les.- It is possible that my carb has been modded and I never e
ven knew it, which would sure refute what I said about every P model runnin
g so well wouldn't it?- I am going to pull that jet and take a look at it
today.- well..... maybe tomorrow!- :-)- =0A=0AThanks again for prese
nting the facts, and Dennis, looks like you were right as well- when you
mentioned it did not start with the PF but with the P's.- Anyway, I stand
corrected and am happy to say so.- =0A=0ANow, back to the gent with the
original problem.- Did his engine stumble when he pushed the power up, or
did the engine die when he pulled it back to idle?- =0A=0AMark Bitterlic
h=0A=0A=0A=0A-=0A=0A=0A=0A________________________________=0AFrom: "KJKim
ball@aol.com" <KJKimball@aol.com>=0ATo: m14pengines-list@matronics.com=0ASe
nt: Monday, December 22, 2008 6:38:18 AM=0ASubject: Re: M14PEngines-List: W
hy would my Yak 52 m14p lose power?=0A=0AThe carb mod was the original idea
of Ben Morphew of McKinney Texas in 1990 to stop the stubble the engine ha
s when advancing the throttle.- Ben was part of a group with Dr Tom ?? wh
o brought in several yak 52s and 3 sukhois in 1990.- These airplanes all
had M14P engines not PF engines since the PF was not available until the la
te 90's.-So, the talk of it only being a PF issue cannot be correct.- B
en has lots of experience with PS5 pressure carbs on Pitts airplanes and kn
ew of a mod made on those PS5 carbs.- This PS5 mod was-done by-Curtis
Pitts and the carb OH facility in FL that Curtis used for his 4 cyl lyc. a
irplanes since the PS5 was designed for engines of more than 400 cubic inch
es.- On the PS5, the accelerator pump diaphragm was limited in travel wit
h a bolt.- =0A=0AIn the M14 carb, there is no accelerator pump diaphragm
instead having an over enrichment jet.- Ben studied the carb data and det
ermined which jet to plug up.- Ben made the mod on-Les Crowder's yak (B
en and Les were neighbors and friends) as a test of his theory and it worke
d great!- So, they began to do the mod to other airplanes since Ben and L
es were seeing airplanes damaged with hard landings and taxi problems due t
o the blubber of the carb.- Les did Yaks and Ben did Sukhois. In 1997, Be
n showed me the mod on an engine here and recommended we do this mod to all
the M14 engine we mess with which we have done.- I then created the "how
-to" instructions on our website.- Again, this blubber can happen with P
engines not just PF and this is shown to be true based on the history and t
ime line of the carb mod.=0A=0ACan you solve the throttle stumble in other
ways?- Sure.- Now we know there are a handful of jets available for thi
s port which can be swapped around you get better performance but it make t
ake several trials to get it right.- The carb mod is simple to do, takes
only minutes and is reversible.- Folks in the non-south can have 2 jets,
one plugged for warm and one unplugged for cold flying as George Coy later
pointed out that the mod works great with the exception of some airplanes o
perated in extreme cold conditions.- The over enrichment jet helps to kee
p the very cold engine running at lower power.=0A=0AAs for carb ice on pres
sure carbs, it is possible and has been shown to have happen on PS5 carbs a
nd on the M14 carb.- I know of a suhkoi that had ice and the owner was ab
le to see the ice on inspection.- I know of a yak 52 in the northwest tha
t had ice on taxi and warm up to the point it locked the throttle in positi
on.- Once shut down and the engine heat warmed the carb body, the ice mel
ted and the throttle operated normally.- It can happen in the right condi
tions.=0A=0AHave Fun,=0A=0AKevin Kimball=0A=0A.- =0A=0A=0A=0A=0A_________
_______________________=0AOne site keeps you connected to all your email: A
======================0A
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
I am glad to know that you have verified that with such a calibrated instru
ment Dennis.- I sure would like to have one of those things!- You were
also correct about the P vs. the PF deal.- I hate to be wrong,-but it a
ppears that I clearly was, and Kevin was there to verify it from the very b
eginning!- =0A=0AMark Bitterlich=0A=0A-=0A=0A=0A=0A____________________
____________=0AFrom: A. Dennis Savarese <dsavarese0812@bellsouth.net>=0ATo:
m14pengines-list@matronics.com=0ASent: Monday, December 22, 2008 4:15:46 A
M=0ASubject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
=0A=0A=0AI acquired the "fix" from our friend George Coy.=0A-=0AAll good
input Mark.- I also agree one can pull the throttle back until one can se
e a slight decrease in MP and save fuel.- This is proven by watching the
JPI fuel flow instrument installed in my airplane as well as others.=0A-
=0ADennis=0A=0A----- Original Message ----- =0AFrom: Yak Pilot =0ATo: m14pe
ngines-list@matronics.com =0ASent: Sunday, December 21, 2008 10:01 PM=0ASub
ject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AW
as not trying to disagree or start an argument with you Dennis .- Just di
d not believe that this cure was applicable to the problem being described.
- Respectfully, I still do not.- =0A=0ARegarding the stumble in throttl
e movement.- I have talked to many people about this pressure carb.- A
lot of people think they have this thing fully figured out and I have some
doubts there since their explanations seem to differ from the mechanics I h
ave talked to that are Russians themselves and were trained in that country
.- I know that my personal understanding is much less than complete to pu
t it mildly.- I do not have the personal first hand experience to back th
is up, but from what I have seen one Russian do, it appears that the "P" mo
del engines that I have seen stumble are usually able to be cured without p
lugging the accel pump.- Some cases have required changing air bleed jets
to values that "by the book" seemed to be rather extreme, but the change t
hen allowed the accel pump jet to be pretty much- left alone, or operated
withinn normal ranges but never plugged.- This is problematic in that th
is puts strong suspicion on proper
operation of the diaphragms in that the-engine was possibly over rich in
the transition -range to begin with. -My comment about P vs. PF engine
s was not meant to imply that the problem could not happen with a P model,
but that in every case I have seen it could be cured by exercising the comp
lete range of adjustments possible with this carb, further that while it ma
y have been tried and used successfully with the P model, that according to
my sources, it was originally intended for the PF model where this problem
happens more often.- I am not sure who "invented" this mod.... Seems to
me I was told once... might have been you, George Coy,- I really am not s
ure.- I hope someone chimes in regarding this so that if I am wrong on th
at point,---I can be corrected.-- Given that there is no magic in
how an engine burns fuel, and that there are a lot of P models that run pe
rfectly without the accel jet plugged, it seems to me that an engine that d
oes
not run right has something out of adjustment (or just not working right i
nternally) and does not need a carb design change.- No question that the
mod works on some engines, but to me it is a matter of robbing Peter to pay
Paul.- =0A=0ABottom line, no one around here has a flow bench for these
things that I know of, or has tried to truly tackle over-hauling one and th
en charting the flow curves on this side of the pond, and since the darn th
ings are no longer in production, long term users may eventually switch to
fuel injection anyway.-- =0A=0AWhile New Bern is not a big airport for
Russian engines,-we have had 5 aircraft with P model engines, all of whic
h ran perfectly without stumble, and another 4 with PF models, ALL of which
stumble some worse than others.- =0A=0A=0AI was told that the carb does
have a circuit for WOT mixture enrichment.- I was also informed the opera
tor can pull the throttle back until a very small change in manifold pressu
re is seen in order to save fuel with minimum performance loss.- Both pie
ces of info came from Russian sources directly, if that means anything.-
=0A-=0AMark Bitterlich=0A-=0A=0A=0A________________________________=0A
=0AFrom: A. Dennis Savarese <dsavarese0812@bellsouth.net>=0ATo: m14pengines
-list@matronics.com=0ASent: Sunday, December 21, 2008 7:00:34 PM=0ASubject:
Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AMark,
=0AThere are many, many M14P's, 360 HP engines that exhibit the throttle re
sponse hesitation.- The problem is not limited to the PF engine only.-
The problem of throttle response hesitation can be reduced by-changing th
e accelerator pump jet down to-a smaller diameter.- The smallest accele
rator pump jet is .9-mm and I can say from experience, changing to the .9
mm jet does not totally eliminate the problem on those engines that exhibi
t the problem.=0A-=0AI too have plugged many an accelerator pump jet to s
top the hesitation problem on both P and PF engines.- My opinion is, the
accelerator pump jet provides additional fuel during WOT-which helps-to
cool the cylinders (richer mixture).- I'm not sure what the long term im
pact might be by plugging the accelerator pump jet.=0A-=0ADennis=0A-=0A
----- Original Message ----- =0AFrom: Yak Pilot =0ATo: m14pengines-list@mat
ronics.com =0ASent: Sunday, December 21, 2008 1:42 PM=0ASubject: Re: Re: M1
4PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AI'll take some fl
ames if necessary, but I feel I must point out that this mod was actually i
ntended for fixing the throttle lag experienced in a lot of M-14PF model en
gines (400HP) and NOT for the M-14P model, which is the straight 360 HP eng
ine.- A normal M-14P engine should run perfectly WITHOUT needing this mod
ification.- =0A=0APoint number two.- Something that has worked normally
in the past, and then suddenly starts working abnormally, or in a way diff
erent from in the past is usually happening because something has changed a
nd not because something needs to be modified.- I think this problem meet
s that description.- =0A=0AThis particular engine lost power when throttl
ed back.- It did not stumble and falter when the throttle was advanced fr
om idle on the deck.- This does not sound like an accelerator pump issue.
... ice possibly, water in the fuel, low fuel pressure, a tank venting prob
lem, you name it... lots of possible causes, but I would be very hesitant t
o recommend the accel pump mod on ANY engine for the described problem.-
=0A=0ARespectfully, =0A=0AMark Bitterlich =0AN50YK.- =0A=0Ap.s.- Run th
is by Sergei Boriak, or better yet Vladimir Yastremski... I think you will
find they will agree.- =0A=0A=0A-=0A=0A=0A=0A__________________________
______=0AFrom: Eddie Moran <eddiemoranii@yahoo.com>=0ATo: m14pengines-list@
matronics.com=0ASent: Saturday, December 20, 2008 11:18:38 AM=0ASubject: Re
: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0A=0ADavid,
<<We're removing a plug to uncover the jet below it.>>- Yes, #10 on the
diagram is the plug (11mm) that you pull to get to the jet.=0A=0AThe jet un
screws, comes out, has a little hole in it.- You plug that somehow..(weld
, JB, etc.).- Then reinsert the jet and reinstall the 11mm plug.- =0A
=0AMy engine ran much better after the mod with no noted lag in acceleratio
n.=0A=0AEddie=0A=0A=0A=0A--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.
ca> wrote:=0A=0AFrom: DAVID STROUD <dstroud@storm.ca>=0ASubject: Re: Re: M1
4PEngines-List: Why would my Yak 52 m14p lose power?=0ATo: m14pengines-list
@matronics.com=0ADate: Saturday, December 20, 2008, 10:32 AM=0A=0A=0AI'm sl
ightly confused now. We're removing a plug to uncover the jet below it. You
r last sentence says--- 'plug it and reinstall' , do you mean to =0Ar
emove the jet, plug it ( the jet ) somehow, then reinstall the plugged jet
and cover it with the first plug? Is this process done on the Huosai =0Aeng
ine too ? thanks..=0A-=0ADavid Stroud---- Ottawa, Canada=0AChrist
avia C-FDWS=0AFairchild 51 replica=0Aunder- construction C-FYXV=0A----- O
riginal Message ----- =0AFrom: Eddie Moran =0ATo: m14pengines-list@matronic
s.com =0ASent: Saturday, December 20, 2008 10:02 AM=0ASubject: Fw: Re: M14P
Engines-List: Why would my Yak 52 m14p lose power?=0A=0AMark,- =0A=0AI am
not an expert by any means but I agree on the ice theory.- I also have a
picture of the accel plug fix.- I would plug that if you have not alread
y.- The following info came from Dennis a few years ago.=0A=0A=0A=0ASee a
ttached.- Item #10 is a plug (11 mm I believe) and under the plug is the
acceleration pump jet.- The jet has a slot in it just like a slotted scre
w.- Use a straight blade screwdriver to remove.- Plug it and reinstall.
=0A=0AThe figure is attached.=0A=0AEddie Moran=0AN320VT =0AMurphy Moose=0A
=0A--- On Thu, 12/18/08, markgreenway <geewhizmark@gmail.com> wrote:=0A=0AF
rom: markgreenway <geewhizmark@gmail.com>=0ASubject: M14PEngines-List: Why
would my Yak 52 m14p lose power?=0ATo: m14pengines-list@matronics.com=0ADat
e: Thursday, December 18, 2008, 9:30 PM=0A=0A=0A--> M14PEngines-List messag
e posted by: "markgreenway"=0A<geewhizmark@gmail.com>=0A=0AHello Guys=0A=0A
Any idea why I lost power and had to make a forced landing ,because whe
n=0Acrossing midfield for landing, the motor lost power when I=0A throttled
back. It=0Anever totally died and it regained power once on the ground=0A
=0A =0A=0A________________________________=0A=0A 3D=3D=3D=3D
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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==
Message 6
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
No it is not inherent to all Radials.? Have a lot of time?behind them and the are
usually smooth as can be on throttle application, unless something is not operating
correctly or out of adjustment..? Gary??? ? CJ,?? N22YK
-----Original Message-----
From: N395V <Bearcat@bearcataviation.com>
Sent: Mon, 22 Dec 2008 5:12 am
Subject: M14PEngines-List: Re: Why would my Yak 52 m14p lose power?
Is not a slight stumble inherent in all radials?
--------
Milt
2003 F1 Rocket
2006 Radial Rocket
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=220504#220504
Message 7
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Kevin, You are correct that Pressure Carbs develope Carb Ice, I have had it happen
on a Navion with a E-225 , and a Bendix PS-5? Carb,. It happend on taxi and
warm up. it was a chilly morning and a bit of ground fog was hanging around
the airport, Was running the engine at 1200 RPM to wait for the oil temp to come
up. all of a sudden the engine began to get slightly rough so I waited and
watched the Tach start dropping off RPM, let it get ot about 900 RPM and then
pulled the carb heat on, within just a few seconds the RPM came back up to 1200..?
So gentelman, Pressure Carbs will develop Carb Ice..
Gary... CJ,??? N22YK
-----Original Message-----
From: KJKimball@aol.com
Sent: Mon, 22 Dec 2008 6:38 am
Subject: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
The carb mod was the original idea of Ben Morphew of McKinney Texas in 1990 to
stop the stubble the engine has when advancing the throttle.? Ben was part of
a group with Dr Tom ?? who brought in several yak 52s and 3 sukhois in 1990.?
These airplanes all had M14P engines not PF engines since the PF was not available
until the late 90's.?So, the talk of it only being a PF issue cannot be correct.?
Ben has lots of experience with PS5 pressure carbs on Pitts airplanes
and knew of a mod made on those PS5 carbs.? This PS5 mod was?done by?Curtis Pitts
and the carb OH facility in FL that Curtis used for his 4 cyl lyc. airplanes
since the PS5 was designed for engines of more than 400 cubic inches.? On
the PS5, the accelerator pump diaphragm was limited in travel with a bolt.?
?
In the M14 carb, there is no accelerator pump diaphragm instead having an over
enrichment jet.? Ben studied the carb data and determined which jet to plug up.?
Ben made the mod on?Les Crowder's yak (Ben and Les were neighbors and friends)
as a test of his theory and it worked great!? So, they began to do the mod
to other airplanes since Ben and Les were seeing airplanes damaged with hard
landings and taxi problems due to the blubber of the carb.? Les did Yaks and Ben
did Sukhois. In 1997, Ben showed me the mod on an engine here and recommended
we do this mod to all the M14 engine we mess with which we have done.? I then
created the "how-to" instructions on our website.? Again, this blubber can
happen with P engines not just PF and this is shown to be true based on the history
and time line of the carb mod.
?
Can you solve the throttle stumble in other ways?? Sure.? Now we know there are
a handful of jets available for this port which can be swapped around you get
better performance but it make take several trials to get it right.? The carb
mod is simple to do, takes only minutes and is reversible.? Folks in the non-south
can have 2 jets, one plugged for warm and one unplugged for cold flying
as George Coy later pointed out that the mod works great with the exception of
some airplanes operated in extreme cold conditions.? The over enrichment jet
helps to keep the very cold engine running at lower power.
?
As for carb ice on pressure carbs, it is possible and has been shown to have happen
on PS5 carbs and on the M14 carb.? I know of a suhkoi that had ice and the
owner was able to see the ice on inspection.? I know of a yak 52 in the northwest
that had ice on taxi and warm up to the point it locked the throttle in
position.? Once shut down and the engine heat warmed the carb body, the ice melted
and the throttle operated normally.? It can happen in the right conditions.
?
Have Fun,
?
Kevin Kimball
?
.?
One site keeps you connected to all your email: AOL Mail, Gmail, and Yahoo Mail.
Try it now.
Message 8
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Actually Mark, the JPI FS-450G is relatively inexpensive. Gulf Coast
and Pacific Coast Avionics are/were offering a $175 mail-in rebate
making the instrument about $305. LOTS of information for $305. Easy
install. If you decide to order one, make sure you order the FS-450G
because the "G" instrument includes the Floscan model 231 transducer.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 10:57 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
I am glad to know that you have verified that with such a calibrated
instrument Dennis. I sure would like to have one of those things! You
were also correct about the P vs. the PF deal. I hate to be wrong, but
it appears that I clearly was, and Kevin was there to verify it from the
very beginning!
Mark Bitterlich
-------------------------------------------------------------------------
-----
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 4:15:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
I acquired the "fix" from our friend George Coy.
All good input Mark. I also agree one can pull the throttle back
until one can see a slight decrease in MP and save fuel. This is proven
by watching the JPI fuel flow instrument installed in my airplane as
well as others.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 10:01 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
Was not trying to disagree or start an argument with you Dennis .
Just did not believe that this cure was applicable to the problem being
described. Respectfully, I still do not.
Regarding the stumble in throttle movement. I have talked to many
people about this pressure carb. A lot of people think they have this
thing fully figured out and I have some doubts there since their
explanations seem to differ from the mechanics I have talked to that are
Russians themselves and were trained in that country. I know that my
personal understanding is much less than complete to put it mildly. I
do not have the personal first hand experience to back this up, but from
what I have seen one Russian do, it appears that the "P" model engines
that I have seen stumble are usually able to be cured without plugging
the accel pump. Some cases have required changing air bleed jets to
values that "by the book" seemed to be rather extreme, but the change
then allowed the accel pump jet to be pretty much left alone, or
operated withinn normal ranges but never plugged. This is problematic
in that this puts strong suspicion on proper operation of the diaphragms
in that the engine was possibly over rich in the transition range to
begin with. My comment about P vs. PF engines was not meant to imply
that the problem could not happen with a P model, but that in every case
I have seen it could be cured by exercising the complete range of
adjustments possible with this carb, further that while it may have been
tried and used successfully with the P model, that according to my
sources, it was originally intended for the PF model where this problem
happens more often. I am not sure who "invented" this mod.... Seems to
me I was told once... might have been you, George Coy, I really am not
sure. I hope someone chimes in regarding this so that if I am wrong on
that point, I can be corrected. Given that there is no magic in how
an engine burns fuel, and that there are a lot of P models that run
perfectly without the accel jet plugged, it seems to me that an engine
that does not run right has something out of adjustment (or just not
working right internally) and does not need a carb design change. No
question that the mod works on some engines, but to me it is a matter of
robbing Peter to pay Paul.
Bottom line, no one around here has a flow bench for these things
that I know of, or has tried to truly tackle over-hauling one and then
charting the flow curves on this side of the pond, and since the darn
things are no longer in production, long term users may eventually
switch to fuel injection anyway.
While New Bern is not a big airport for Russian engines, we have had
5 aircraft with P model engines, all of which ran perfectly without
stumble, and another 4 with PF models, ALL of which stumble some worse
than others.
I was told that the carb does have a circuit for WOT mixture
enrichment. I was also informed the operator can pull the throttle back
until a very small change in manifold pressure is seen in order to save
fuel with minimum performance loss. Both pieces of info came from
Russian sources directly, if that means anything.
Mark Bitterlich
-------------------------------------------------------------------------
---
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 7:00:34 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
Mark,
There are many, many M14P's, 360 HP engines that exhibit the
throttle response hesitation. The problem is not limited to the PF
engine only. The problem of throttle response hesitation can be reduced
by changing the accelerator pump jet down to a smaller diameter. The
smallest accelerator pump jet is .9 mm and I can say from experience,
changing to the .9 mm jet does not totally eliminate the problem on
those engines that exhibit the problem.
I too have plugged many an accelerator pump jet to stop the
hesitation problem on both P and PF engines. My opinion is, the
accelerator pump jet provides additional fuel during WOT which helps to
cool the cylinders (richer mixture). I'm not sure what the long term
impact might be by plugging the accelerator pump jet.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 1:42 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
I'll take some flames if necessary, but I feel I must point out
that this mod was actually intended for fixing the throttle lag
experienced in a lot of M-14PF model engines (400HP) and NOT for the
M-14P model, which is the straight 360 HP engine. A normal M-14P engine
should run perfectly WITHOUT needing this modification.
Point number two. Something that has worked normally in the past,
and then suddenly starts working abnormally, or in a way different from
in the past is usually happening because something has changed and not
because something needs to be modified. I think this problem meets that
description.
This particular engine lost power when throttled back. It did not
stumble and falter when the throttle was advanced from idle on the deck.
This does not sound like an accelerator pump issue.... ice possibly,
water in the fuel, low fuel pressure, a tank venting problem, you name
it... lots of possible causes, but I would be very hesitant to recommend
the accel pump mod on ANY engine for the described problem.
Respectfully,
Mark Bitterlich
N50YK.
p.s. Run this by Sergei Boriak, or better yet Vladimir
Yastremski... I think you will find they will agree.
-------------------------------------------------------------------------
-
From: Eddie Moran <eddiemoranii@yahoo.com>
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 11:18:38 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
David, << We're removing a plug to uncover the jet below
it.>> Yes, #10 on the diagram is the plug (11mm) that you pull to get
to the jet.
The jet unscrews, comes out, has a little hole in it. You
plug that somehow..(weld, JB, etc.). Then reinsert the jet and
reinstall the 11mm plug.
My engine ran much better after the mod with no noted lag in
acceleration.
Eddie
--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.ca> wrote:
From: DAVID STROUD <dstroud@storm.ca>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52
m14p lose power?
To: m14pengines-list@matronics.com
Date: Saturday, December 20, 2008, 10:32 AM
I'm slightly confused now. We're removing a plug to
uncover the jet below it. Your last sentence says 'plug it and
reinstall' , do you mean to
remove the jet, plug it ( the jet ) somehow, then
reinstall the plugged jet and cover it with the first plug? Is this
process done on the Huosai
engine too ? thanks..
David Stroud Ottawa, Canada
Christavia C-FDWS
Fairchild 51 replica
under construction C-FYXV
----- Original Message -----
From: Eddie Moran
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 10:02 AM
Subject: Fw: Re: M14PEngines-List: Why would my Yak 52
m14p lose power?
Mark,
I am not an expert by any means but I
agree on the ice theory. I also have a picture of the accel plug fix.
I would plug that if you have not already. The following info came from
Dennis a few years ago.
See attached. Item #10 is a plug (11 mm I
believe) and under the plug is the acceleration pump jet. The jet has a
slot in it just like a slotted screw. Use a straight blade screwdriver
to remove. Plug it and reinstall.
The figure is attached.
Eddie Moran
N320VT
Murphy Moose
--- On Thu, 12/18/08, markgreenway
<geewhizmark@gmail.com> wrote:
From: markgreenway
<geewhizmark@gmail.com>
Subject: M14PEngines-List: Why would my
Yak 52 m14p lose power?
To: m14pengines-list@matronics.com
Date: Thursday, December 18, 2008, 9:30
PM
"markgreenway"<geewhizmark@gmail.com>Hello Guys Any idea why I lost
power and had to make a forced landing ,because whencrossing midfield
for landing, the motor lost power when I throttled back. Itnever totally
died and it regained power once on the ground
--------------------------------------------------------
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
GREAT INFO!- =0A=0AThanks!=0A=0AMark=0A=0A-=0A=0A=0A=0A________________
________________=0AFrom: A. Dennis Savarese <dsavarese0812@bellsouth.net>
=0ATo: m14pengines-list@matronics.com=0ASent: Monday, December 22, 2008 9:2
5:46 AM=0ASubject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?=0A=0A=0AActually Mark, the JPI FS-450G is relatively inexpensive.-
Gulf Coast and Pacific Coast Avionics are/were offering a $175-mail-in r
ebate making the instrument about $305.- LOTS of information for $305.-
Easy install.- If you decide to order one, make sure you order the FS-45
0G because the "G" instrument includes the Floscan model 231 transducer.=0A
Dennis=0A----- Original Message ----- =0AFrom: Yak Pilot =0ATo: m14pengines
-list@matronics.com =0ASent: Monday, December 22, 2008 10:57 AM=0ASubject:
Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AI am gl
ad to know that you have verified that with such a calibrated instrument De
nnis.- I sure would like to have one of those things!- You were also co
rrect about the P vs. the PF deal.- I hate to be wrong,-but it appears
that I clearly was, and Kevin was there to verify it from the very beginnin
g!- =0A=0AMark Bitterlich=0A=0A-=0A=0A=0A=0A___________________________
_____=0AFrom: A. Dennis Savarese <dsavarese0812@bellsouth.net>=0ATo: m14pen
gines-list@matronics.com=0ASent: Monday, December 22, 2008 4:15:46 AM=0ASub
ject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0A
=0AI acquired the "fix" from our friend George Coy.=0A-=0AAll good input
Mark.- I also agree one can pull the throttle back until one can see a sl
ight decrease in MP and save fuel.- This is proven by watching the JPI fu
el flow instrument installed in my airplane as well as others.=0A-=0ADenn
is=0A=0A----- Original Message ----- =0AFrom: Yak Pilot =0ATo: m14pengines-
list@matronics.com =0ASent: Sunday, December 21, 2008 10:01 PM=0ASubject: R
e: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AWas not
trying to disagree or start an argument with you Dennis .- Just did not b
elieve that this cure was applicable to the problem being described.- Res
pectfully, I still do not.- =0A=0ARegarding the stumble in throttle movem
ent.- I have talked to many people about this pressure carb.- A lot of
people think they have this thing fully figured out and I have some doubts
there since their explanations seem to differ from the mechanics I have tal
ked to that are Russians themselves and were trained in that country.- I
know that my personal understanding is much less than complete to put it mi
ldly.- I do not have the personal first hand experience to back this up,
but from what I have seen one Russian do, it appears that the "P" model eng
ines that I have seen stumble are usually able to be cured without plugging
the accel pump.- Some cases have required changing air bleed jets to val
ues that "by the book" seemed to be rather extreme, but the change then all
owed the accel pump jet to be pretty much- left alone, or operated within
n normal ranges but never plugged.- This is problematic in that this puts
strong suspicion on proper
operation of the diaphragms in that the-engine was possibly over rich in
the transition -range to begin with. -My comment about P vs. PF engine
s was not meant to imply that the problem could not happen with a P model,
but that in every case I have seen it could be cured by exercising the comp
lete range of adjustments possible with this carb, further that while it ma
y have been tried and used successfully with the P model, that according to
my sources, it was originally intended for the PF model where this problem
happens more often.- I am not sure who "invented" this mod.... Seems to
me I was told once... might have been you, George Coy,- I really am not s
ure.- I hope someone chimes in regarding this so that if I am wrong on th
at point,---I can be corrected.-- Given that there is no magic in
how an engine burns fuel, and that there are a lot of P models that run pe
rfectly without the accel jet plugged, it seems to me that an engine that d
oes
not run right has something out of adjustment (or just not working right i
nternally) and does not need a carb design change.- No question that the
mod works on some engines, but to me it is a matter of robbing Peter to pay
Paul.- =0A=0ABottom line, no one around here has a flow bench for these
things that I know of, or has tried to truly tackle over-hauling one and th
en charting the flow curves on this side of the pond, and since the darn th
ings are no longer in production, long term users may eventually switch to
fuel injection anyway.-- =0A=0AWhile New Bern is not a big airport for
Russian engines,-we have had 5 aircraft with P model engines, all of whic
h ran perfectly without stumble, and another 4 with PF models, ALL of which
stumble some worse than others.- =0A=0A=0AI was told that the carb does
have a circuit for WOT mixture enrichment.- I was also informed the opera
tor can pull the throttle back until a very small change in manifold pressu
re is seen in order to save fuel with minimum performance loss.- Both pie
ces of info came from Russian sources directly, if that means anything.-
=0A-=0AMark Bitterlich=0A-=0A=0A=0A________________________________=0A
=0AFrom: A. Dennis Savarese <dsavarese0812@bellsouth.net>=0ATo: m14pengines
-list@matronics.com=0ASent: Sunday, December 21, 2008 7:00:34 PM=0ASubject:
Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AMark,
=0AThere are many, many M14P's, 360 HP engines that exhibit the throttle re
sponse hesitation.- The problem is not limited to the PF engine only.-
The problem of throttle response hesitation can be reduced by-changing th
e accelerator pump jet down to-a smaller diameter.- The smallest accele
rator pump jet is .9-mm and I can say from experience, changing to the .9
mm jet does not totally eliminate the problem on those engines that exhibi
t the problem.=0A-=0AI too have plugged many an accelerator pump jet to s
top the hesitation problem on both P and PF engines.- My opinion is, the
accelerator pump jet provides additional fuel during WOT-which helps-to
cool the cylinders (richer mixture).- I'm not sure what the long term im
pact might be by plugging the accelerator pump jet.=0A-=0ADennis=0A-=0A
----- Original Message ----- =0AFrom: Yak Pilot =0ATo: m14pengines-list@mat
ronics.com =0ASent: Sunday, December 21, 2008 1:42 PM=0ASubject: Re: Re: M1
4PEngines-List: Why would my Yak 52 m14p lose power?=0A=0AI'll take some fl
ames if necessary, but I feel I must point out that this mod was actually i
ntended for fixing the throttle lag experienced in a lot of M-14PF model en
gines (400HP) and NOT for the M-14P model, which is the straight 360 HP eng
ine.- A normal M-14P engine should run perfectly WITHOUT needing this mod
ification.- =0A=0APoint number two.- Something that has worked normally
in the past, and then suddenly starts working abnormally, or in a way diff
erent from in the past is usually happening because something has changed a
nd not because something needs to be modified.- I think this problem meet
s that description.- =0A=0AThis particular engine lost power when throttl
ed back.- It did not stumble and falter when the throttle was advanced fr
om idle on the deck.- This does not sound like an accelerator pump issue.
... ice possibly, water in the fuel, low fuel pressure, a tank venting prob
lem, you name it... lots of possible causes, but I would be very hesitant t
o recommend the accel pump mod on ANY engine for the described problem.-
=0A=0ARespectfully, =0A=0AMark Bitterlich =0AN50YK.- =0A=0Ap.s.- Run th
is by Sergei Boriak, or better yet Vladimir Yastremski... I think you will
find they will agree.- =0A=0A=0A-=0A=0A=0A=0A__________________________
______=0AFrom: Eddie Moran <eddiemoranii@yahoo.com>=0ATo: m14pengines-list@
matronics.com=0ASent: Saturday, December 20, 2008 11:18:38 AM=0ASubject: Re
: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?=0A=0A=0ADavid,
<<We're removing a plug to uncover the jet below it.>>- Yes, #10 on the
diagram is the plug (11mm) that you pull to get to the jet.=0A=0AThe jet un
screws, comes out, has a little hole in it.- You plug that somehow..(weld
, JB, etc.).- Then reinsert the jet and reinstall the 11mm plug.- =0A
=0AMy engine ran much better after the mod with no noted lag in acceleratio
n.=0A=0AEddie=0A=0A=0A=0A--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.
ca> wrote:=0A=0AFrom: DAVID STROUD <dstroud@storm.ca>=0ASubject: Re: Re: M1
4PEngines-List: Why would my Yak 52 m14p lose power?=0ATo: m14pengines-list
@matronics.com=0ADate: Saturday, December 20, 2008, 10:32 AM=0A=0A=0AI'm sl
ightly confused now. We're removing a plug to uncover the jet below it. You
r last sentence says--- 'plug it and reinstall' , do you mean to =0Ar
emove the jet, plug it ( the jet ) somehow, then reinstall the plugged jet
and cover it with the first plug? Is this process done on the Huosai =0Aeng
ine too ? thanks..=0A-=0ADavid Stroud---- Ottawa, Canada=0AChrist
avia C-FDWS=0AFairchild 51 replica=0Aunder- construction C-FYXV=0A----- O
riginal Message ----- =0AFrom: Eddie Moran =0ATo: m14pengines-list@matronic
s.com =0ASent: Saturday, December 20, 2008 10:02 AM=0ASubject: Fw: Re: M14P
Engines-List: Why would my Yak 52 m14p lose power?=0A=0AMark,- =0A=0AI am
not an expert by any means but I agree on the ice theory.- I also have a
picture of the accel plug fix.- I would plug that if you have not alread
y.- The following info came from Dennis a few years ago.=0A=0A=0A=0ASee a
ttached.- Item #10 is a plug (11 mm I believe) and under the plug is the
acceleration pump jet.- The jet has a slot in it just like a slotted scre
w.- Use a straight blade screwdriver to remove.- Plug it and reinstall.
=0A=0AThe figure is attached.=0A=0AEddie Moran=0AN320VT =0AMurphy Moose=0A
=0A--- On Thu, 12/18/08, markgreenway <geewhizmark@gmail.com> wrote:=0A=0AF
rom: markgreenway <geewhizmark@gmail.com>=0ASubject: M14PEngines-List: Why
would my Yak 52 m14p lose power?=0ATo: m14pengines-list@matronics.com=0ADat
e: Thursday, December 18, 2008, 9:30 PM=0A=0A=0A--> M14PEngines-List messag
e posted by: "markgreenway"=0A<geewhizmark@gmail.com>=0A=0AHello Guys=0A=0A
Any idea why I lost power and had to make a forced landing ,because whe
n=0Acrossing midfield for landing, the motor lost power when I=0A throttled
back. It=0Anever totally died and it regained power once on the ground=0A
=0A =0A=0A________________________________=0A=0A 3D=3D=3D=3D
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Not that anyone cares.... but just to add to our knowledge base.- My M14
is a "B", had the same problem and was cured by the jet mod.
Eddie Moran
--- On Mon, 12/22/08, Yak Pilot <yakplt@yahoo.com> wrote:
From: Yak Pilot <yakplt@yahoo.com>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
GREAT INFO!-
-
Thanks!
-
Mark
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Monday, December 22, 2008 9:25:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv1188514940 DIV {
MARGIN:0px;}
Actually Mark, the JPI FS-450G is relatively inexpensive.- Gulf Coast and
Pacific Coast Avionics are/were offering a $175-mail-in rebate making th
e instrument about $305.- LOTS of information for $305.- Easy install.
- If you decide to order one, make sure you order the FS-450G because the
"G" instrument includes the Floscan model 231 transducer.
Dennis
----- Original Message -----
From: Yak Pilot
Sent: Monday, December 22, 2008 10:57 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I am glad to know that you have verified that with such a calibrated instru
ment Dennis.- I sure would like to have one of those things!- You were
also correct about the P vs. the PF deal.- I hate to be wrong,-but it a
ppears that I clearly was, and Kevin was there to verify it from the very b
eginning!-
-
Mark Bitterlich
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Monday, December 22, 2008 4:15:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv1188514940 DIV {
MARGIN:0px;}
I acquired the "fix" from our friend George Coy.
-
All good input Mark.- I also agree one can pull the throttle back until o
ne can see a slight decrease in MP and save fuel.- This is proven by watc
hing the JPI fuel flow instrument installed in my airplane as well as other
s.
-
Dennis
-
----- Original Message -----
From: Yak Pilot
Sent: Sunday, December 21, 2008 10:01 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
Was not trying to disagree or start an argument with you Dennis .- Just d
id not believe that this cure was applicable to the problem being described
.- Respectfully, I still do not.-
-
Regarding the stumble in throttle movement.- I have talked to many people
about this pressure carb.- A lot of people think they have this thing fu
lly figured out and I have some doubts there since their explanations seem
to differ from the mechanics I have talked to that are Russians themselves
and were trained in that country.- I know that my personal understanding
is much less than complete to put it mildly.- I do not have the personal
first hand experience to back this up, but from what I have seen one Russia
n do, it appears that the "P" model engines that I have seen stumble are us
ually able to be cured without plugging the accel pump.- Some cases have
required changing air bleed jets to values that "by the book" seemed to be
rather extreme, but the change then allowed the accel pump jet to be pretty
much- left alone, or operated withinn normal ranges but never plugged.
- This is problematic in that this puts
strong suspicion on proper operation of the diaphragms in that the-engin
e was possibly over rich in the transition -range to begin with. -My co
mment about P vs. PF engines was not meant to imply that the problem could
not happen with a P model, but that in every case I have seen it could be c
ured by exercising the complete range of adjustments possible with this car
b, further that while it may have been tried and used successfully with the
P model, that according to my sources, it was originally intended for the
PF model where this problem happens more often.- I am not sure who "inven
ted" this mod.... Seems to me I was told once... might have been you, Georg
e Coy,- I really am not sure.- I hope someone chimes in regarding this
so that if I am wrong on that point,---I can be corrected.-- Give
n that there is no magic in how an engine burns fuel, and that there are a
lot of P models that run perfectly
without the accel jet plugged, it seems to me that an engine that does not
run right has something out of adjustment (or just not working right inter
nally) and does not need a carb design change.- No question that the mod
works on some engines, but to me it is a matter of robbing Peter to pay Pau
l.-
-
Bottom line, no one around here has a flow bench for these things that I kn
ow of, or has tried to truly tackle over-hauling one and then charting the
flow curves on this side of the pond, and since the darn things are no long
er in production, long term users may eventually switch to fuel injection a
nyway.--
-
While New Bern is not a big airport for Russian engines,-we have had 5 ai
rcraft with P model engines, all of which ran perfectly without stumble, an
d another 4 with PF models, ALL of which stumble some worse than others.-
I was told that the carb does have a circuit for WOT mixture enrichment.-
I was also informed the operator can pull the throttle back until a very s
mall change in manifold pressure is seen in order to save fuel with minimum
performance loss.- Both pieces of info came from Russian sources directl
y, if that means anything.-
-
Mark Bitterlich
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Sunday, December 21, 2008 7:00:34 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv1188514940 DIV {MARGIN:0px;}
Mark,
There are many, many M14P's, 360 HP engines that exhibit the throttle respo
nse hesitation.- The problem is not limited to the PF engine only.- The
problem of throttle response hesitation can be reduced by-changing the a
ccelerator pump jet down to-a smaller diameter.- The smallest accelerat
or pump jet is .9-mm and I can say from experience, changing to the .9 mm
jet does not totally eliminate the problem on those engines that exhibit t
he problem.
-
I too have plugged many an accelerator pump jet to stop the hesitation prob
lem on both P and PF engines.- My opinion is, the accelerator pump jet pr
ovides additional fuel during WOT-which helps-to cool the cylinders (ri
cher mixture).- I'm not sure what the long term impact might be by pluggi
ng the accelerator pump jet.
-
Dennis
-
----- Original Message -----
From: Yak Pilot
Sent: Sunday, December 21, 2008 1:42 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I'll take some flames if necessary, but I feel I must point out that this m
od was actually intended for fixing the throttle lag experienced in a lot o
f M-14PF model engines (400HP) and NOT for the M-14P model, which is the st
raight 360 HP engine.- A normal M-14P engine should run perfectly WITHOUT
needing this modification.-
-
Point number two.- Something that has worked normally in the past, and th
en suddenly starts working abnormally, or in a way different from in the pa
st is usually happening because something has changed and not because somet
hing needs to be modified.- I think this problem meets that description.
-
-
This particular engine lost power when throttled back.- It did not stumbl
e and falter when the throttle was advanced from idle on the deck.- This
does not sound like an accelerator pump issue.... ice possibly, water in th
e fuel, low fuel pressure, a tank venting problem, you name it... lots of p
ossible causes, but I would be very hesitant to recommend the accel pump mo
d on ANY engine for the described problem.-
-
Respectfully,
-
Mark Bitterlich
N50YK.-
-
p.s.- Run this by Sergei Boriak, or better yet Vladimir Yastremski... I t
hink you will find they will agree.-
-
-
From: Eddie Moran <eddiemoranii@yahoo.com>
Sent: Saturday, December 20, 2008 11:18:38 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
David, << We're removing a plug to uncover the jet below it.>>- Yes, #10
on the diagram is the plug (11mm) that you pull to get to the jet.
The jet unscrews, comes out, has a little hole in it.- You plug that some
how..(weld, JB, etc.).- Then reinsert the jet and reinstall the 11mm plug
.-
My engine ran much better after the mod with no noted lag in acceleration.
Eddie
--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.ca> wrote:
From: DAVID STROUD <dstroud@storm.ca>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I'm slightly confused now. We're removing a plug to uncover the jet below i
t. Your last sentence says--- 'plug it and reinstall' , do you mean t
o
remove the jet, plug it ( the jet ) somehow, then reinstall the plugged jet
and cover it with the first plug? Is this process done on the Huosai
engine too ? thanks..
-
David Stroud---- Ottawa, Canada
Christavia C-FDWS
Fairchild 51 replica
under- construction C-FYXV
----- Original Message -----
From: Eddie Moran
Sent: Saturday, December 20, 2008 10:02 AM
Subject: Fw: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
Mark,-
I am not an expert by any means but I agree on the ice theory.- I also ha
ve a picture of the accel plug fix.- I would plug that if you have not al
ready.- The following info came from Dennis a few years ago.
See attached.- Item #10 is a plug (11 mm I believe) and under the plug is
the acceleration pump jet.- The jet has a slot in it just like a slotted
screw.- Use a straight blade screwdriver to remove.- Plug it and reins
tall.
The figure is attached.
Eddie Moran
N320VT
Murphy Moose
--- On Thu, 12/18/08, markgreenway <geewhizmark@gmail.com> wrote:
From: markgreenway <geewhizmark@gmail.com>
Subject: M14PEngines-List: Why would my Yak 52 m14p lose power?
<geewhizmark@gmail.com>
Hello Guys
Any idea why I lost power and had to make a forced landing ,because whe
n
crossing midfield for landing, the motor lost power when I
throttled back. It
never totally died and it regained power once on the ground
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
By the "same problem" I was referring to the hesitation when "advancing" th
e thrust lever.
--- On Mon, 12/22/08, Eddie Moran <eddiemoranii@yahoo.com> wrote:
From: Eddie Moran <eddiemoranii@yahoo.com>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
Not that anyone cares.... but just to add to our knowledge base.- My M14
is a "B", had the same problem and was cured by the jet mod.
Eddie Moran
--- On Mon, 12/22/08, Yak Pilot <yakplt@yahoo.com> wrote:
From: Yak Pilot <yakplt@yahoo.com>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
GREAT INFO!-
-
Thanks!
-
Mark
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Monday, December 22, 2008 9:25:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv881181695 #yiv1188514940 DIV {
MARGIN:0px;}
Actually Mark, the JPI FS-450G is relatively inexpensive.- Gulf Coast and
Pacific Coast Avionics are/were offering a $175-mail-in rebate making th
e instrument about $305.- LOTS of information for $305.- Easy install.
- If you decide to order one, make sure you order the FS-450G because the
"G" instrument includes the Floscan model 231 transducer.
Dennis
----- Original Message -----
From: Yak Pilot
Sent: Monday, December 22, 2008 10:57 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I am glad to know that you have verified that with such a calibrated instru
ment Dennis.- I sure would like to have one of those things!- You were
also correct about the P vs. the PF deal.- I hate to be wrong,-but it a
ppears that I clearly was, and Kevin was there to verify it from the very b
eginning!-
-
Mark Bitterlich
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Monday, December 22, 2008 4:15:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv881181695 #yiv1188514940 DIV {
MARGIN:0px;}
I acquired the "fix" from our friend George Coy.
-
All good input Mark.- I also agree one can pull the throttle back until o
ne can see a slight decrease in MP and save fuel.- This is proven by watc
hing the JPI fuel flow instrument installed in my airplane as well as other
s.
-
Dennis
-
----- Original Message -----
From: Yak Pilot
Sent: Sunday, December 21, 2008 10:01 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
Was not trying to disagree or start an argument with you Dennis .- Just d
id not believe that this cure was applicable to the problem being described
.- Respectfully, I still do not.-
-
Regarding the stumble in throttle movement.- I have talked to many people
about this pressure carb.- A lot of people think they have this thing fu
lly figured out and I have some doubts there since their explanations seem
to differ from the mechanics I have talked to that are Russians themselves
and were trained in that country.- I know that my personal understanding
is much less than complete to put it mildly.- I do not have the personal
first hand experience to back this up, but from what I have seen one Russia
n do, it appears that the "P" model engines that I have seen stumble are us
ually able to be cured without plugging the accel pump.- Some cases have
required changing air bleed jets to values that "by the book" seemed to be
rather extreme, but the change then allowed the accel pump jet to be pretty
much- left alone, or operated withinn normal ranges but never plugged.
- This is problematic in that this puts
strong suspicion on proper operation of the diaphragms in that the-engin
e was possibly over rich in the transition -range to begin with. -My co
mment about P vs. PF engines was not meant to imply that the problem could
not happen with a P model, but that in every case I have seen it could be c
ured by exercising the complete range of adjustments possible with this car
b, further that while it may have been tried and used successfully with the
P model, that according to my sources, it was originally intended for the
PF model where this problem happens more often.- I am not sure who "inven
ted" this mod.... Seems to me I was told once... might have been you, Georg
e Coy,- I really am not sure.- I hope someone chimes in regarding this
so that if I am wrong on that point,---I can be corrected.-- Give
n that there is no magic in how an engine burns fuel, and that there are a
lot of P models that run perfectly
without the accel jet plugged, it seems to me that an engine that does not
run right has something out of adjustment (or just not working right inter
nally) and does not need a carb design change.- No question that the mod
works on some engines, but to me it is a matter of robbing Peter to pay Pau
l.-
-
Bottom line, no one around here has a flow bench for these things that I kn
ow of, or has tried to truly tackle over-hauling one and then charting the
flow curves on this side of the pond, and since the darn things are no long
er in production, long term users may eventually switch to fuel injection a
nyway.--
-
While New Bern is not a big airport for Russian engines,-we have had 5 ai
rcraft with P model engines, all of which ran perfectly without stumble, an
d another 4 with PF models, ALL of which stumble some worse than others.-
I was told that the carb does have a circuit for WOT mixture enrichment.-
I was also informed the operator can pull the throttle back until a very s
mall change in manifold pressure is seen in order to save fuel with minimum
performance loss.- Both pieces of info came from Russian sources directl
y, if that means anything.-
-
Mark Bitterlich
-
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
Sent: Sunday, December 21, 2008 7:00:34 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
#yiv881181695 #yiv1188514940 DIV {MARGIN:0px;}
Mark,
There are many, many M14P's, 360 HP engines that exhibit the throttle respo
nse hesitation.- The problem is not limited to the PF engine only.- The
problem of throttle response hesitation can be reduced by-changing the a
ccelerator pump jet down to-a smaller diameter.- The smallest accelerat
or pump jet is .9-mm and I can say from experience, changing to the .9 mm
jet does not totally eliminate the problem on those engines that exhibit t
he problem.
-
I too have plugged many an accelerator pump jet to stop the hesitation prob
lem on both P and PF engines.- My opinion is, the accelerator pump jet pr
ovides additional fuel during WOT-which helps-to cool the cylinders (ri
cher mixture).- I'm not sure what the long term impact might be by pluggi
ng the accelerator pump jet.
-
Dennis
-
----- Original Message -----
From: Yak Pilot
Sent: Sunday, December 21, 2008 1:42 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I'll take some flames if necessary, but I feel I must point out that this m
od was actually intended for fixing the throttle lag experienced in a lot o
f M-14PF model engines (400HP) and NOT for the M-14P model, which is the st
raight 360 HP engine.- A normal M-14P engine should run perfectly WITHOUT
needing this modification.-
-
Point number two.- Something that has worked normally in the past, and th
en suddenly starts working abnormally, or in a way different from in the pa
st is usually happening because something has changed and not because somet
hing needs to be modified.- I think this problem meets that description.
-
-
This particular engine lost power when throttled back.- It did not stumbl
e and falter when the throttle was advanced from idle on the deck.- This
does not sound like an accelerator pump issue.... ice possibly, water in th
e fuel, low fuel pressure, a tank venting problem, you name it... lots of p
ossible causes, but I would be very hesitant to recommend the accel pump mo
d on ANY engine for the described problem.-
-
Respectfully,
-
Mark Bitterlich
N50YK.-
-
p.s.- Run this by Sergei Boriak, or better yet Vladimir Yastremski... I t
hink you will find they will agree.-
-
-
From: Eddie Moran <eddiemoranii@yahoo.com>
Sent: Saturday, December 20, 2008 11:18:38 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
David, << We're removing a plug to uncover the jet below it.>>- Yes, #10
on the diagram is the plug (11mm) that you pull to get to the jet.
The jet unscrews, comes out, has a little hole in it.- You plug that some
how..(weld, JB, etc.).- Then reinsert the jet and reinstall the 11mm plug
.-
My engine ran much better after the mod with no noted lag in acceleration.
Eddie
--- On Sat, 12/20/08, DAVID STROUD <dstroud@storm.ca> wrote:
From: DAVID STROUD <dstroud@storm.ca>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
I'm slightly confused now. We're removing a plug to uncover the jet below i
t. Your last sentence says--- 'plug it and reinstall' , do you mean t
o
remove the jet, plug it ( the jet ) somehow, then reinstall the plugged jet
and cover it with the first plug? Is this process done on the Huosai
engine too ? thanks..
-
David Stroud---- Ottawa, Canada
Christavia C-FDWS
Fairchild 51 replica
under- construction C-FYXV
----- Original Message -----
From: Eddie Moran
Sent: Saturday, December 20, 2008 10:02 AM
Subject: Fw: Re: M14PEngines-List: Why would my Yak 52 m14p lose power?
Mark,-
I am not an expert by any means but I agree on the ice theory.- I also ha
ve a picture of the accel plug fix.- I would plug that if you have not al
ready.- The following info came from Dennis a few years ago.
See attached.- Item #10 is a plug (11 mm I believe) and under the plug is
the acceleration pump jet.- The jet has a slot in it just like a slotted
screw.- Use a straight blade screwdriver to remove.- Plug it and reins
tall.
The figure is attached.
Eddie Moran
N320VT
Murphy Moose
--- On Thu, 12/18/08, markgreenway <geewhizmark@gmail.com> wrote:
From: markgreenway <geewhizmark@gmail.com>
Subject: M14PEngines-List: Why would my Yak 52 m14p lose power?
<geewhizmark@gmail.com>
Hello Guys
Any idea why I lost power and had to make a forced landing ,because whe
n
crossing midfield for landing, the motor lost power when I
throttled back. It
never totally died and it regained power once on the ground
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| Subject: | Re: Why would my Yak 52 m14p lose power? |
Eddie, the B and the P have the same carburetor. The only difference
between the B and the P is the nose case. R and R the nose case on the
B with a nose case from a P and you have a P engine.
Dennis
----- Original Message -----
From: Eddie Moran
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 3:50 PM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p lose
power?
By the "same problem" I was referring to the hesitation when
"advancing" the thrust lever.
--- On Mon, 12/22/08, Eddie Moran <eddiemoranii@yahoo.com>
wrote:
From: Eddie Moran <eddiemoranii@yahoo.com>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52 m14p
lose power?
To: m14pengines-list@matronics.com
Date: Monday, December 22, 2008, 1:45 PM
Not that anyone cares.... but just to add to our
knowledge base. My M14 is a "B", had the same problem and was cured by
the jet mod.
Eddie Moran
--- On Mon, 12/22/08, Yak Pilot <yakplt@yahoo.com>
wrote:
From: Yak Pilot <yakplt@yahoo.com>
Subject: Re: Re: M14PEngines-List: Why would my Yak 52
m14p lose power?
To: m14pengines-list@matronics.com
Date: Monday, December 22, 2008, 1:31 PM
GREAT INFO!
Thanks!
Mark
--------------------------------------------------------------
From: A. Dennis Savarese <dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 9:25:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak 52
m14p lose power?
Actually Mark, the JPI FS-450G is relatively
inexpensive. Gulf Coast and Pacific Coast Avionics are/were offering a
$175 mail-in rebate making the instrument about $305. LOTS of
information for $305. Easy install. If you decide to order one, make
sure you order the FS-450G because the "G" instrument includes the
Floscan model 231 transducer.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 10:57 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak
52 m14p lose power?
I am glad to know that you have verified that with
such a calibrated instrument Dennis. I sure would like to have one of
those things! You were also correct about the P vs. the PF deal. I
hate to be wrong, but it appears that I clearly was, and Kevin was there
to verify it from the very beginning!
Mark Bitterlich
------------------------------------------------------------
From: A. Dennis Savarese
<dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Monday, December 22, 2008 4:15:46 AM
Subject: Re: Re: M14PEngines-List: Why would my Yak
52 m14p lose power?
I acquired the "fix" from our friend George Coy.
All good input Mark. I also agree one can pull the
throttle back until one can see a slight decrease in MP and save fuel.
This is proven by watching the JPI fuel flow instrument installed in my
airplane as well as others.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 10:01 PM
Subject: Re: Re: M14PEngines-List: Why would my
Yak 52 m14p lose power?
Was not trying to disagree or start an argument
with you Dennis . Just did not believe that this cure was applicable to
the problem being described. Respectfully, I still do not.
Regarding the stumble in throttle movement. I
have talked to many people about this pressure carb. A lot of people
think they have this thing fully figured out and I have some doubts
there since their explanations seem to differ from the mechanics I have
talked to that are Russians themselves and were trained in that country.
I know that my personal understanding is much less than complete to put
it mildly. I do not have the personal first hand experience to back
this up, but from what I have seen one Russian do, it appears that the
"P" model engines that I have seen stumble are usually able to be cured
without plugging the accel pump. Some cases have required changing air
bleed jets to values that "by the book" seemed to be rather extreme, but
the change then allowed the accel pump jet to be pretty much left
alone, or operated withinn normal ranges but never plugged. This is
problematic in that this puts strong suspicion on proper operation of
the diaphragms in that the engine was possibly over rich in the
transition range to begin with. My comment about P vs. PF engines was
not meant to imply that the problem could not happen with a P model, but
that in every case I have seen it could be cured by exercising the
complete range of adjustments possible with this carb, further that
while it may have been tried and used successfully with the P model,
that according to my sources, it was originally intended for the PF
model where this problem happens more often. I am not sure who
"invented" this mod.... Seems to me I was told once... might have been
you, George Coy, I really am not sure. I hope someone chimes in
regarding this so that if I am wrong on that point, I can be
corrected. Given that there is no magic in how an engine burns fuel,
and that there are a lot of P models that run perfectly without the
accel jet plugged, it seems to me that an engine that does not run right
has something out of adjustment (or just not working right internally)
and does not need a carb design change. No question that the mod works
on some engines, but to me it is a matter of robbing Peter to pay Paul.
Bottom line, no one around here has a flow bench
for these things that I know of, or has tried to truly tackle
over-hauling one and then charting the flow curves on this side of the
pond, and since the darn things are no longer in production, long term
users may eventually switch to fuel injection anyway.
While New Bern is not a big airport for Russian
engines, we have had 5 aircraft with P model engines, all of which ran
perfectly without stumble, and another 4 with PF models, ALL of which
stumble some worse than others.
I was told that the carb does have a circuit for
WOT mixture enrichment. I was also informed the operator can pull the
throttle back until a very small change in manifold pressure is seen in
order to save fuel with minimum performance loss. Both pieces of info
came from Russian sources directly, if that means anything.
Mark Bitterlich
----------------------------------------------------------
From: A. Dennis Savarese
<dsavarese0812@bellsouth.net>
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 7:00:34 PM
Subject: Re: Re: M14PEngines-List: Why would my
Yak 52 m14p lose power?
Mark,
There are many, many M14P's, 360 HP engines that
exhibit the throttle response hesitation. The problem is not limited to
the PF engine only. The problem of throttle response hesitation can be
reduced by changing the accelerator pump jet down to a smaller diameter.
The smallest accelerator pump jet is .9 mm and I can say from
experience, changing to the .9 mm jet does not totally eliminate the
problem on those engines that exhibit the problem.
I too have plugged many an accelerator pump jet to
stop the hesitation problem on both P and PF engines. My opinion is,
the accelerator pump jet provides additional fuel during WOT which helps
to cool the cylinders (richer mixture). I'm not sure what the long term
impact might be by plugging the accelerator pump jet.
Dennis
----- Original Message -----
From: Yak Pilot
To: m14pengines-list@matronics.com
Sent: Sunday, December 21, 2008 1:42 PM
Subject: Re: Re: M14PEngines-List: Why would my
Yak 52 m14p lose power?
I'll take some flames if necessary, but I feel I
must point out that this mod was actually intended for fixing the
throttle lag experienced in a lot of M-14PF model engines (400HP) and
NOT for the M-14P model, which is the straight 360 HP engine. A normal
M-14P engine should run perfectly WITHOUT needing this modification.
Point number two. Something that has worked
normally in the past, and then suddenly starts working abnormally, or in
a way different from in the past is usually happening because something
has changed and not because something needs to be modified. I think
this problem meets that description.
This particular engine lost power when throttled
back. It did not stumble and falter when the throttle was advanced from
idle on the deck. This does not sound like an accelerator pump
issue.... ice possibly, water in the fuel, low fuel pressure, a tank
venting problem, you name it... lots of possible causes, but I would be
very hesitant to recommend the accel pump mod on ANY engine for the
described problem.
Respectfully,
Mark Bitterlich
N50YK.
p.s. Run this by Sergei Boriak, or better yet
Vladimir Yastremski... I think you will find they will agree.
--------------------------------------------------------
From: Eddie Moran <eddiemoranii@yahoo.com>
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 11:18:38 AM
Subject: Re: Re: M14PEngines-List: Why would my
Yak 52 m14p lose power?
David, << We're removing a plug to uncover
the jet below it.>> Yes, #10 on the diagram is the plug (11mm) that you
pull to get to the jet.
The jet unscrews, comes out, has a little
hole in it. You plug that somehow..(weld, JB, etc.). Then reinsert the
jet and reinstall the 11mm plug.
My engine ran much better after the mod
with no noted lag in acceleration.
Eddie
--- On Sat, 12/20/08, DAVID STROUD
<dstroud@storm.ca> wrote:
From: DAVID STROUD <dstroud@storm.ca>
Subject: Re: Re: M14PEngines-List: Why
would my Yak 52 m14p lose power?
To: m14pengines-list@matronics.com
Date: Saturday, December 20, 2008, 10:32
AM
I'm slightly confused now. We're
removing a plug to uncover the jet below it. Your last sentence says
'plug it and reinstall' , do you mean to
remove the jet, plug it ( the jet )
somehow, then reinstall the plugged jet and cover it with the first
plug? Is this process done on the Huosai
engine too ? thanks..
David Stroud Ottawa, Canada
Christavia C-FDWS
Fairchild 51 replica
under construction C-FYXV
----- Original Message -----
From: Eddie Moran
To: m14pengines-list@matronics.com
Sent: Saturday, December 20, 2008 10:02
AM
Subject: Fw: Re: M14PEngines-List: Why
would my Yak 52 m14p lose power?
Mark,
I am not an expert by any means but I
agree on the ice theory. I also have a picture of the accel plug fix.
I would plug that if you have not already. The following info came from
Dennis a few years ago.
See attached. Item #10 is a plug (11 mm
I believe) and under the plug is the acceleration pump jet. The jet has
a slot in it just like a slotted screw. Use a straight blade
screwdriver to remove. Plug it and reinstall.
The figure is attached.
Eddie Moran
N320VT
Murphy Moose
--- On Thu, 12/18/08, markgreenway
<geewhizmark@gmail.com> wrote:
From: markgreenway
<geewhizmark@gmail.com>
Subject: M14PEngines-List: Why would my
Yak 52 m14p lose power?
To: m14pengines-list@matronics.com
Date: Thursday, December 18, 2008, 9:30
PM
"markgreenway"<geewhizmark@gmail.com>Hello Guys Any idea why I lost
power and had to make a forced landing ,because whencrossing midfield
for landing, the motor lost power when I throttled back. Itnever totally
died and it regained power once on the ground
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