Today's Message Index:
----------------------
1. 04:40 AM - Re: Question about High EGTs on a 912 (Richard Girard)
2. 07:37 AM - Re: Question about High EGTs on a 912 (FLYaDIVE)
3. 09:29 AM - Re: Question about High EGTs on a 912 (Les Goldner)
4. 09:50 AM - Re: Question about High EGTs on a 912 (Scott DeMeyer)
5. 09:50 AM - 912 "cylinder type" (Les Goldner)
6. 10:55 AM - Re: Question about High EGTs on a 912 (FLYaDIVE)
Message 1
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| Subject: | Re: Question about High EGTs on a 912 |
Just a thought, but with only one mag operating you're dumping some raw gas
out into the exhaust that burns right over your EGT sensors. That would
account for the higher EGT's.
Rick Girard
On Tue, Apr 27, 2010 at 11:51 PM, Les Goldner
<lgold@quantum-associates.com>wrote:
> After flying my Zenith 701 w/a Rotax 912ULS a few hundred miles at 5100
> RPM yesterday I noticed an EGT problem. Toward the end of the flight, wit
h
> OAT about 65F at 2000=92, the EGTs started creeping up to 1620F (the maxi
mum
> allowed temp) on one exhaust and about 1590F on the other. It dropped whe
n I
> reduced RPM to 4000 or raised it to 5500RPM.
>
> When I noticed this, I looked around. After getting my head out of a
> clouds, I also noticed the engine was running on a single mag. I am hopin
g
> that this was the cause of the overheating, although I don=92t understand
why
> this should be so.
>
> It=92s going to be raining here (in N. California) for a few days. Since
I
> can=92t fly to check out if running on both mags will bring the EGTs down
, I
> was wondering if anyone in Rotax land had an opinion about whether runnin
g
> on a single mag could causing the high EGTs. If you don=92t think runnin
g on
> a single mag caused the problem, and you have seen this before, I could u
se
> advice as to how to proceed before tearing the carbs apart.
>
> When I can fly again, I=92ll report if the mag issue was the culprit here
.
>
> Les
>
>
> *
>
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> *
>
>
Message 2
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| Subject: | Re: Question about High EGTs on a 912 |
Les:
Rich hit the nail on the head. Unburnt gas burning in the exhaust
pipes will increase your EGT.
Prove it to yourself... Fly with ans without a Mag on.
Barry
On Wed, Apr 28, 2010 at 12:51 AM, Les Goldner
<lgold@quantum-associates.com> wrote:
> After flying my Zenith 701 w/a Rotax 912ULS a few hundred miles at 5100 RPM
> yesterday I noticed an EGT problem. Toward the end of the flight, with OAT
> about 65F at 2000, the EGTs started creeping up to 1620F (the maximum
> allowed temp) on one exhaust and about 1590F on the other. It dropped when I
> reduced RPM to 4000 or raised it to 5500RPM.
>
> When I noticed this, I looked around. After getting my head out of a clouds,
> I also noticed the engine was running on a single mag. I am hoping that this
> was the cause of the overheating, although I dont understand why this
> should be so.
>
> Its going to be raining here (in N. California) for a few days. Since I
> cant fly to check out if running on both mags will bring the EGTs down, I
> was wondering if anyone in Rotax land had an opinion about whether running
> on a single mag could causing the high EGTs. If you dont think running on
> a single mag caused the problem, and you have seen this before, I could use
> advice as to how to proceed before tearing the carbs apart.
>
> When I can fly again, Ill report if the mag issue was the culprit here.
>
> Les
>
>
Message 3
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| Subject: | Question about High EGTs on a 912 |
Barry and Rick,
I hope you guys are right. I'll let you know in a few days when I can fly
again.
FYI, In my 2-stroke Rotax 503, extra gas (i.e., rich burn) decreases temps,
but this I a little different situation.
Les
-----Original Message-----
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of FLYaDIVE
Sent: Wednesday, April 28, 2010 7:23 AM
Subject: Re: RotaxEngines-List: Question about High EGTs on a 912
Les:
Rich hit the nail on the head. Unburnt gas burning in the exhaust
pipes will increase your EGT.
Prove it to yourself... Fly with ans without a Mag on.
Barry
On Wed, Apr 28, 2010 at 12:51 AM, Les Goldner
<lgold@quantum-associates.com> wrote:
> After flying my Zenith 701 w/a Rotax 912ULS a few hundred miles at 5100
RPM
> yesterday I noticed an EGT problem. Toward the end of the flight, with OAT
> about 65F at 2000, the EGTs started creeping up to 1620F (the maximum
> allowed temp) on one exhaust and about 1590F on the other. It dropped when
I
> reduced RPM to 4000 or raised it to 5500RPM.
>
> When I noticed this, I looked around. After getting my head out of a
clouds,
> I also noticed the engine was running on a single mag. I am hoping that
this
> was the cause of the overheating, although I dont understand why this
> should be so.
>
> Its going to be raining here (in N. California) for a few days. Since I
> cant fly to check out if running on both mags will bring the EGTs down, I
> was wondering if anyone in Rotax land had an opinion about whether running
> on a single mag could causing the high EGTs. If you dont think running
on
> a single mag caused the problem, and you have seen this before, I could
use
> advice as to how to proceed before tearing the carbs apart.
>
> When I can fly again, Ill report if the mag issue was the culprit here.
>
> Les
>
>
Message 4
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| Subject: | Re: Question about High EGTs on a 912 |
Hmm, I don't understand how there could be much, if any unburnt gas in the
exhaust pipe while running on one ignition module. It is my understanding t
hat both plugs fire at the same time on a 912. I would think you would need
a lot of raw fuel to make EGT increase that much. How could there be enoug
h unburnt gas to make a difference? I would suspect something else like a p
lugged jet or intake vacuum leak.
I know I've had many issues with the carb sockets coming apart. This substa
ntially increased my EGT.
Scott
--- On Wed, 4/28/10, FLYaDIVE <flyadive@gmail.com> wrote:
From: FLYaDIVE <flyadive@gmail.com>
Subject: Re: RotaxEngines-List: Question about High EGTs on a 912
Les:
Rich hit the nail on the head.=C2- Unburnt gas burning in the exhaust
pipes will increase your EGT.
Prove it to yourself... Fly with ans without a Mag on.
Barry
On Wed, Apr 28, 2010 at 12:51 AM, Les Goldner
<lgold@quantum-associates.com> wrote:
> After flying my Zenith 701 w/a Rotax 912ULS a few hundred miles at 5100 R
PM
> yesterday I noticed an EGT problem. Toward the end of the flight, with OA
T
> about 65F at 2000=99, the EGTs started creeping up to 1620F (the ma
ximum
> allowed temp) on one exhaust and about 1590F on the other. It dropped whe
n I
> reduced RPM to 4000 or raised it to 5500RPM.
>
> When I noticed this, I looked around. After getting my head out of a clou
ds,
> I also noticed the engine was running on a single mag. I am hoping that t
his
> was the cause of the overheating, although I don=99t understand why
this
> should be so.
>
> It=99s going to be raining here (in N. California) for a few days.
=C2- Since I
> can=99t fly to check out if running on both mags will bring the EGT
s down, I
> was wondering if anyone in Rotax land had an opinion about whether runnin
g
> on a single mag could causing the high EGTs.=C2- If you don=99t t
hink running on
> a single mag caused the problem, and you have seen this before, I could u
se
> advice as to how to proceed before tearing the carbs apart.
>
> When I can fly again, I=99ll report if the mag issue was the culpri
t here.
>
> Les
>
>
-
List
S WEB FORUMS -
on Web Site -
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
Message 5
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| Subject: | 912 "cylinder type" |
I had my engine oil analyzed by Aviation Laboratories. They came back and
said they can't tell if everything is normal until they know what "cylinder
type" is in my 912ULS.
I don't know what "cylinder type" comes in a 912ULS and didn't know
different cylinder types were available. Can someone clue me in here?
Thanks,
Les
Message 6
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| Subject: | Re: Question about High EGTs on a 912 |
Hi Scott:
With a dual Mag system you are correct... Both Mags fire at the same time.
Or SHOULD!
If because of timing or poor connection they do not there will probably be
a
poor burn in the cylinder and incomplete burnt fuel will be pushed out the
exhause pipes.
The average EGT is between 1300 to 1400 F. So jumping from 1400 to 1600 is
only a 200 F jump. That is not much - But it is a temp we do not want to
see.
Cars have experimented with CATALYTIC CONVERTS to burn the incomplete burnt
fuel and they get quite hot. Of course that is also because of the
catalytic element. And burning fuel in the exhaust system with spark plugs
and nichrome wire have also been tried. All this to reduce out exhaust
emissions.
Barry
On Wed, Apr 28, 2010 at 12:27 PM, Scott DeMeyer <scottsr1100rt@yahoo.com>wr
ote:
> Hmm, I don't understand how there could be much, if any unburnt gas in
> the exhaust pipe while running on one ignition module. It is my
> understanding that both plugs fire at the same time on a 912. I would thi
nk
> you would need a lot of raw fuel to make EGT increase that much. How coul
d
> there be enough unburnt gas to make a difference? I would suspect somethi
ng
> else like a plugged jet or intake vacuum leak.
>
> I know I've had many issues with the carb sockets coming apart. This
> substantially increased my EGT.
>
> Scott
>
> --- On *Wed, 4/28/10, FLYaDIVE <flyadive@gmail.com>* wrote:
>
>
> From: FLYaDIVE <flyadive@gmail.com>
>
> Subject: Re: RotaxEngines-List: Question about High EGTs on a 912
> To: rotaxengines-list@matronics.com
> Date: Wednesday, April 28, 2010, 7:23 AM
>
ttp://mc/compose?to=flyadive@gmail.com>
> >
>
> Les:
>
> Rich hit the nail on the head. Unburnt gas burning in the exhaust
> pipes will increase your EGT.
>
> Prove it to yourself... Fly with ans without a Mag on.
>
>
> Barry
>
> On Wed, Apr 28, 2010 at 12:51 AM, Les Goldner
> <lgold@quantum-associates.com<http://mc/compose?to=lgold@quantum-associ
ates.com>>
> wrote:
> > After flying my Zenith 701 w/a Rotax 912ULS a few hundred miles at 5100
> RPM
> > yesterday I noticed an EGT problem. Toward the end of the flight, with
> OAT
> > about 65F at 2000=92, the EGTs started creeping up to 1620F (the maximu
m
> > allowed temp) on one exhaust and about 1590F on the other. It dropped
> when I
> > reduced RPM to 4000 or raised it to 5500RPM.
> >
> > When I noticed this, I looked around. After getting my head out of a
> clouds,
> > I also noticed the engine was running on a single mag. I am hoping that
> this
> > was the cause of the overheating, although I don=92t understand why thi
s
> > should be so.
> >
> > It=92s going to be raining here (in N. California) for a few days. Sin
ce I
> > can=92t fly to check out if running on both mags will bring the EGTs do
wn,
> I
> > was wondering if anyone in Rotax land had an opinion about whether
> running
> > on a single mag could causing the high EGTs. If you don=92t think runn
ing
> on
> > a single mag caused the problem, and you have seen this before, I could
> use
> > advice as to how to proceed before tearing the carbs apart.
> >
> > When I can fly again, I=92ll report if the mag issue was the culprit he
re.
> >
> > Les
> >
> >
> >
> >
>
> http://www.matronics.com/Navigator?RotaxEngines-List -->
> http://www.matronics.com/contribution <http://forums.matronics.com/>
>
>
> *
>
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> *
>
>
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