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1. 09:16 AM - Fuel Mixture ()
2. 10:00 AM - Re: Fuel Mixture (sjbeaver)
3. 10:02 PM - Re: Fuel Mixture ()
Message 1
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I have the 4 cylinder engine with supercharger, fuel injection and automatic
mixture control. The motor was factory reconditioned in 2003 and has had
Zero hours since
I started the motor recently and there are loud "pops" out of the exhaust.
An AME on the field thought that it was running lean.
Fuel pressure is good
I see that I can adjust the mixture at the fuel pump but want to ask if
there is something else I should check for first.
Has anybody opened the fuel pump, are there any seals that would have
deteriorated. From the drawing I cannot see if there are any seals that may
need replacing.
Thanks
Mike
Mike Pienaar
m <mailto:ike@vision499.com> ike@vision499.com
Home: +1 250-999-8121
Mike cell: +1 250-885-0554
1-1100 Tulip Ave, Victoria, BC, V8Z 0A2
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Message 2
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| Subject: | Re: Fuel Mixture |
Mike.
There are no o-rings in the fuel inject system to be concerned about and
I would suggest that you do not disassemble it. It is a complex and very
precise device! - What you might do, however, is remove the drain plug
on the underside of the unit and allow any accumulated oil to drain out.
If sitting for a long time excess oil can accumulate in the pump and
interfere with the mixture.
Let me run through some of the other items you might check. I am not
implying that there is any part of the manual you have not digested.
Just making sure I don't omit anything :)
First and foremost (If I had a $ for every time I explain this . . . )
is the automatic mixture system. People used to operating American
engines seem to think that the engine should always be operated at the
most rich setting available. That is just not the case with the LOM and
doing so so will have serval rather bad consequences.
Look closely at the mixture control arm that extends from the side of
the fuel injection pump. There is a slot in the arm, inside of which is
a small pointer. Also on the side of the pump is a shiny metal plate
shaped like a pizza slice on which are marked the mixture settings.
Something like +3, +2, +1, N, -1, -2 with the -2 being nearest the top.
Adjust your mixture control mechanism so that the "normal" (all phases
of operation below 10,000') corresponds to the pointer being aligned
with the 'N' mark. - Actually 'N' inside a circle. Now you know the
mixture is set exactly as it should be. Again - do not operate the
engine at the full rich setting. Doing so will disable the automatic
mixture system, foul the plugs, wash lubricant from the cylinder walls
and other bad things.
Next, start the engine and let it warm up for an extended period. When
the oil temp is up in the 100F area, carefully and with the appropriate
precautions run the engine at full power (super charger engaged) Switch
from both to magneto 1. What RPM drop do you see? Go back to both, then
magneto 2. Again, what RPM drop do you see? I would expect a drop in the
25-35 RPM area. Anything other than that suggests your ignition timing
is a little out. It is a simple matter to loosen the magneto clamps and
rotate the mags a little until the 25-35 RPM drop is observed. Why not
just time the mags with a buzz box in the traditional manner? For two
reasons: 1) This is how the manual says to do it and 2) these magnetos
have automatic advance and retard systems so static timing means almost
nothing.
How that the mixture and the ignition timing are up to snuff, you can do
some testing. Operate the engine for as long as is reasonable at a
cruise sort of power setting. Say 25" of manifold pressure. (It doesn't
matter if the super charger is engaged or not). Now shut down and
observe the exhaust pipes. Are they back and sooty, a very light gray
(almost white) or a nice mid gray, the color of a slate roof? - We want
the slate color.
If in doubt, remove the spark plugs and see what they look like.
Another useful trick (if you have straight pipes) is to run the engine
in the dark and look into the exhaust pipes of the running engine. At
medium power settings look for a nice blue flame tinged with yellow to
indicate the ideal running conditions.
Finally, since I see you are in BC, you could contact Pavol Novak who
now resides at Qualcom Beach on Victoria Island. He is a Czech LOM
factory trained technician and expert on the engines (and Zlin
airframes)
Steve
--
Stephen Beaver
Tel: 614-937 4189
> On Aug 18, 2020, at 12:14 PM, <mike@vision499.com>
<mike@vision499.com> wrote:
>
> I have the 4 cylinder engine with supercharger, fuel injection and
automatic mixture control. The motor was factory reconditioned in 2003
and has had
> Zero hours since
>
> I started the motor recently and there are loud =9Cpops=9D
out of the exhaust. An AME on the field thought that it was running
lean.
>
> Fuel pressure is good
>
> I see that I can adjust the mixture at the fuel pump but want to ask
if there is something else I should check for first.
>
> Has anybody opened the fuel pump, are there any seals that would have
deteriorated. =46rom the drawing I cannot see if there are any seals
that may need replacing.
>
> Thanks
>
> Mike
>
> Mike Pienaar
> mike@vision499.com <mailto:ike@vision499.com>
> Home: +1 250-999-8121
> Mike cell: +1 250-885-0554
> 1-1100 Tulip Ave, Victoria, BC, V8Z 0A2
>
>
>
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Message 3
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Hello Steve,
Thanks you so very much for the detailed reply, I really appreciate it. I d
id not make myself very clear, I have the fuel pump with the adjustment nut
at the rear and not the pump with the =9Cpizza slice=9D but ju
dging from what you said I don=99t think it will make a difference.
I will follow your testing procedure and let you know what happens
I just wanted some confirmation that it is safe to run the engine even thou
gh it is =9Cpopping=9D
I have the propeller with reverse thrust, under the reverse thrust control
module there is what appears to be a solenoid and an oil leak developed at
the solenoid seal that was due to an =9Co=9D ring that had lost
all elasticity. I was fearful that there may be more instances of this. Ca
n you suggest anything else that I should replace or renew.
Do you think that I could remove the reverse thrust module completely and c
onnect directly from the governor to the hub?
I have met with Pavel and he welded up my engine mount for me but have not
had contact for a few years.
I have also heard that the magneto seals and harnesses are not good quality
and should be replaced and would appreciate your opinion
Thanks again
Mike
From: owner-lom-list-server@matronics.com <owner-lom-list-server@matronics.
com> On Behalf Of sjbeaver
Sent: August 18, 2020 10:00 AM
Subject: Re: Lom-List: Fuel Mixture
Mike.
There are no o-rings in the fuel inject system to be concerned about and I
would suggest that you do not disassemble it. It is a complex and very prec
ise device! - What you might do, however, is remove the drain plug on the u
nderside of the unit and allow any accumulated oil to drain out. If sitting
for a long time excess oil can accumulate in the pump and interfere with t
he mixture.
Let me run through some of the other items you might check. I am not implyi
ng that there is any part of the manual you have not digested. Just making
sure I don't omit anything :)
First and foremost (If I had a $ for every time I explain this . . . ) is
the automatic mixture system. People used to operating American engines see
m to think that the engine should always be operated at the most rich setti
ng available. That is just not the case with the LOM and doing so so will h
ave serval rather bad consequences.
Look closely at the mixture control arm that extends from the side of the f
uel injection pump. There is a slot in the arm, inside of which is a small
pointer. Also on the side of the pump is a shiny metal plate shaped like a
pizza slice on which are marked the mixture settings. Something like +3, +2
, +1, N, -1, -2 with the -2 being nearest the top. Adjust your mixture cont
rol mechanism so that the "normal" (all phases of operation below 10,000')
corresponds to the pointer being aligned with the 'N' mark. - Actually 'N'
inside a circle. Now you know the mixture is set exactly as it should be. A
gain - do not operate the engine at the full rich setting. Doing so will di
sable the automatic mixture system, foul the plugs, wash lubricant from the
cylinder walls and other bad things.
Next, start the engine and let it warm up for an extended period. When the
oil temp is up in the 100F area, carefully and with the appropriate precaut
ions run the engine at full power (super charger engaged) Switch from both
to magneto 1. What RPM drop do you see? Go back to both, then magneto 2. Ag
ain, what RPM drop do you see? I would expect a drop in the 25-35 RPM area.
Anything other than that suggests your ignition timing is a little out. It
is a simple matter to loosen the magneto clamps and rotate the mags a litt
le until the 25-35 RPM drop is observed. Why not just time the mags with a
buzz box in the traditional manner? For two reasons: 1) This is how the man
ual says to do it and 2) these magnetos have automatic advance and retard s
ystems so static timing means almost nothing.
How that the mixture and the ignition timing are up to snuff, you can do so
me testing. Operate the engine for as long as is reasonable at a cruise sor
t of power setting. Say 25" of manifold pressure. (It doesn't matter if the
super charger is engaged or not). Now shut down and observe the exhaust pi
pes. Are they back and sooty, a very light gray (almost white) or a nice mi
d gray, the color of a slate roof? - We want the slate color.
If in doubt, remove the spark plugs and see what they look like.
Another useful trick (if you have straight pipes) is to run the engine in t
he dark and look into the exhaust pipes of the running engine. At medium po
wer settings look for a nice blue flame tinged with yellow to indicate the
ideal running conditions.
Finally, since I see you are in BC, you could contact Pavol Novak who now r
esides at Qualcom Beach on Victoria Island. He is a Czech LOM factory train
ed technician and expert on the engines (and Zlin airframes)
Steve
--
Stephen Beaver
Tel: 614-937 4189
On Aug 18, 2020, at 12:14 PM, <mike@vision499.com <mailto:mike@vision499.co
m> > <mike@vision499.com <mailto:mike@vision499.com> > wrote:
I have the 4 cylinder engine with supercharger, fuel injection and automati
c mixture control. The motor was factory reconditioned in 2003 and has had
Zero hours since
I started the motor recently and there are loud =9Cpops=9D out
of the exhaust. An AME on the field thought that it was running lean.
Fuel pressure is good
I see that I can adjust the mixture at the fuel pump but want to ask if the
re is something else I should check for first.
Has anybody opened the fuel pump, are there any seals that would have deter
iorated. From the drawing I cannot see if there are any seals that may need
replacing.
Thanks
Mike
Mike Pienaar
mike@vision499.com <mailto:ike@vision499.com>
Home: +1 250-999-8121
Mike cell: +1 250-885-0554
1-1100 Tulip Ave, Victoria, BC, V8Z 0A2
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