Today's Message Index:
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1. 10:08 AM - Re: rough running at 3400 RPM and above (kyle Ponsford)
2. 11:44 AM - Re: Re: rough running at 3400 RPM and above (John Hauck)
3. 01:49 PM - Re: Re: rough running at 3400 RPM and above (=?utf-8?Q?J=C3=B3hann_Gestur_J=C3=B3hannsson?=)
4. 04:22 PM - Re: rough running at 3400 RPM and above (kyle Ponsford)
Message 1
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| Subject: | Re: rough running at 3400 RPM and above |
Doug,
Your descriptions read as if I had written them myself, therefore I was very eager
to read to the bottom and see your eventual solution, but I found... NOTHING!
Did you ever solve your problem? I have not.
My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500 RPM
but after that it stumbles/vibrates so badly that it looses power and refuses
to push through 4100. but when I pull carb-heat it immediately smooths out and
allows me to push it to 4300 RPMs for short periods before falling off dramatically.
With the carb-heat "solution" I too came to the early opinion that I was
running lean.
But I have one significant difference from yours: my plugs are so sooty black they
foul about every third flight when I change them. Which leads me to think
our identical problems are not plug or fuel related.
(I had been running rich plugs to attempt to balance my white #4 cylinder plug
due to a factory recognized poor design of the intake header. I have since changed
my strategy but that is another issue).
I have torn apart my fuel system from one end to the other, cleaned carbs, checked
jets, replaced seals and vitnum tipped needles, reset float levels, changed
plugs and adjusted plug gaps many times, re-attached the plug wires in their
seats and boots, etc. etc.
Each time I spend days messing with it until I seem to have solved the problem,
go for a few flights before the problem comes back, first small vibrations at
the higher end, then more significant vibrations and at progressively lower RPMs
until it becomes unflyable again. This has gone on for three years and has
greatly mangled my enthusiasm for flying as it keeps me circling my private strip
in frustration.
Speculations:
Recently I had a loose alternator belt on my truck and the engine started to loose
power and run very poorly but it continued to run at low RPMs.
I tightened the belt and solved my problem.
It got me to thinking that I may be having a similar problem with my magnetos.
This is so recent a thought that I have not yet began to explore how to check
my mags when the engine won't run in the region that needs testing.
Then I found your thread here.
PLEASE tell me you finally figured out the actual solution but failed to post it
here! I am very, very interested.
- Kyle
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=428766#428766
Message 2
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| Subject: | Re: rough running at 3400 RPM and above |
My first flight to Alaska in 1994, my 912 had a similar problem.
Eventually raised the fuel needles one notch and corrected the problem.
Seems the old 80 horse is really sensitive to lean conditions at midrange.
The way I eventually discovered the fix was pulling the enricher full on
during flight at about 4,200 rpm. The engine gained 200 rpm.
john h
mkIII
Titus, Alabama
-----Original Message-----
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of kyle
Ponsford
Sent: Tuesday, August 19, 2014 12:07 PM
Subject: RotaxEngines-List: Re: rough running at 3400 RPM and above
--> <wild_kyle@hotmail.com>
Doug,
Your descriptions read as if I had written them myself, therefore I was very
eager to read to the bottom and see your eventual solution, but I found...
NOTHING!
Did you ever solve your problem? I have not.
My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500
RPM but after that it stumbles/vibrates so badly that it looses power and
refuses to push through 4100. but when I pull carb-heat it immediately
smooths out and allows me to push it to 4300 RPMs for short periods before
falling off dramatically. With the carb-heat "solution" I too came to the
early opinion that I was running lean.
But I have one significant difference from yours: my plugs are so sooty
black they foul about every third flight when I change them. Which leads me
to think our identical problems are not plug or fuel related.
(I had been running rich plugs to attempt to balance my white #4 cylinder
plug due to a factory recognized poor design of the intake header. I have
since changed my strategy but that is another issue).
I have torn apart my fuel system from one end to the other, cleaned carbs,
checked jets, replaced seals and vitnum tipped needles, reset float levels,
changed plugs and adjusted plug gaps many times, re-attached the plug wires
in their seats and boots, etc. etc.
Each time I spend days messing with it until I seem to have solved the
problem, go for a few flights before the problem comes back, first small
vibrations at the higher end, then more significant vibrations and at
progressively lower RPMs until it becomes unflyable again. This has gone on
for three years and has greatly mangled my enthusiasm for flying as it keeps
me circling my private strip in frustration.
Speculations:
Recently I had a loose alternator belt on my truck and the engine started to
loose power and run very poorly but it continued to run at low RPMs.
I tightened the belt and solved my problem.
It got me to thinking that I may be having a similar problem with my
magnetos. This is so recent a thought that I have not yet began to explore
how to check my mags when the engine won't run in the region that needs
testing.
Then I found your thread here.
PLEASE tell me you finally figured out the actual solution but failed to
post it here! I am very, very interested.
- Kyle
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=428766#428766
Message 3
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| Subject: | Re: rough running at 3400 RPM and above |
Hello Kyle.
My friend had the exact same problem you have. He had been messing with his Rotax
912 ul engine since he bought it. Same as your experiance, seemed to have solved
it but the rough running always came back. Finally he found the problem.
The Stator was the original part and had been a recallmon that part, but it had
not been replaced at the correct time.
So my advice is to replace the stator. You can find the recall information from
the Rotax on the stator.
Hope this helps,
Johann G.
Sent from my iPad
> On Aug 19, 2014, at 5:06 PM, "kyle Ponsford" <wild_kyle@hotmail.com> wrote:
>
>
> Doug,
> Your descriptions read as if I had written them myself, therefore I was very
eager to read to the bottom and see your eventual solution, but I found... NOTHING!
> Did you ever solve your problem? I have not.
>
> My early model Rotax 912UL with Bing 64 carbs runs very smooth up to 3500 RPM
but after that it stumbles/vibrates so badly that it looses power and refuses
to push through 4100. but when I pull carb-heat it immediately smooths out and
allows me to push it to 4300 RPMs for short periods before falling off dramatically.
With the carb-heat "solution" I too came to the early opinion that I
was running lean.
> But I have one significant difference from yours: my plugs are so sooty black
they foul about every third flight when I change them. Which leads me to think
our identical problems are not plug or fuel related.
> (I had been running rich plugs to attempt to balance my white #4 cylinder plug
due to a factory recognized poor design of the intake header. I have since changed
my strategy but that is another issue).
>
> I have torn apart my fuel system from one end to the other, cleaned carbs, checked
jets, replaced seals and vitnum tipped needles, reset float levels, changed
plugs and adjusted plug gaps many times, re-attached the plug wires in their
seats and boots, etc. etc.
> Each time I spend days messing with it until I seem to have solved the problem,
go for a few flights before the problem comes back, first small vibrations
at the higher end, then more significant vibrations and at progressively lower
RPMs until it becomes unflyable again. This has gone on for three years and has
greatly mangled my enthusiasm for flying as it keeps me circling my private
strip in frustration.
>
> Speculations:
> Recently I had a loose alternator belt on my truck and the engine started to
loose power and run very poorly but it continued to run at low RPMs.
> I tightened the belt and solved my problem.
> It got me to thinking that I may be having a similar problem with my magnetos.
This is so recent a thought that I have not yet began to explore how to check
my mags when the engine won't run in the region that needs testing.
> Then I found your thread here.
> PLEASE tell me you finally figured out the actual solution but failed to post
it here! I am very, very interested.
>
> - Kyle
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=428766#428766
>
>
>
>
>
>
>
>
>
>
Message 4
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| Subject: | Re: rough running at 3400 RPM and above |
Johann G.,
I am grateful for your information/suggestion and will tackle that idea immediately!
Thanks,
- Kyle
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=428799#428799
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