Today's Message Index:
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1. 05:10 AM - Re: Rough running 912 UL (h&jeuropa)
2. 06:11 AM - Re: Rough running 912 ULRough running 912 ULRough running 912 (Catz631@aol.com)
3. 06:22 AM - Re: Rough running 912 ULRough running 912 ULRough running 912 (Catz631@aol.com)
4. 09:49 AM - Re: RotaxEngines-List Digest: 5 Msgs - 09/07/16 (John Elling)
5. 05:57 PM - Re: Re: RotaxEngines-List Digest: 5 Msgs - 09/07/16 (bjones@dmv.com)
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| Subject: | Re: Rough running 912 UL |
Hugh,
Since you get the same result when you run on either ignition module, chances are
the problem is not the ignition modules or other electrical issue.
Like the others, we suggest you get your carbs rebuilt. Not only do carbs need
inspection every 200 hours, they contain rubber parts so they fall under the
5 year replacement requirement. Likely the o-rings are hard, the diaphragms are
stiff and the needles are worn.
We went to the school at LEAF several years ago and after seeing how they totally
strip them and replace all wear items, we decided it was a good investment
to have someone who rebuilds carbs every day do ours rather than doing it ourselves.
Ours have been rebuilt twice in 770 hours and we've been very happy with
our decision. Each year at condition inspection, we check carb balance but
no adjustment is necessary.
Jim & Heather
Europa XS, 914 770 hous
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=460369#460369
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| Subject: | Re: Rough running 912 ULRough running 912 ULRough running |
912
Hugh,
I had the same type of problem a couple of years ago. I went thru all the
checks as you have. Actually I have had that problem a few times. One time
it was a broken internal wire coming from the back of the engine to the
module. I found it with a needle and an ohm meter. (forgot the proper name but
it was the red one)
Another time I trimmed the ignition leads and replaced the spark plug caps
after the trimming didn't work. The new caps worked as a couple of old
ones checked bad resistance wise.
By the way on another occasion I replaced the plugs with new ones and still
had a misfire problem. When I "bomb" checked the "new " plugs,2 of them
were bad and I had to replace those again !
These engines can be a nightmare (at least mine) I have often thought about
putting Velcro on my cowling so I can remove it easier!
Again keep us posted if you find the problem because it will quite likely
happen to any one of us
Dick Maddux
912 UL
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| Subject: | Re: Rough running 912 ULRough running 912 ULRough running |
912
Hugh,
John does bring up a point with the needle settings in the carb. The last
2 years my mag checks in the winter have not been good on the ground. I
would have a drop of about 300 rpm on each one. Now if I did a mag check in
the air they were fine. I couldn't figure it out. I live in
hot,muggy,steamy,FLAT Florida (I miss mountains) The temps don't get very cold
here but I
think John might have a solution to my problem. When the weather warms up my
mag problem goes away.
Will see what this winter brings (hurry up winter !!!!!!!)
Dick Maddux
912 UL
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| Subject: | Re: RotaxEngines-List Digest: 5 Msgs - 09/07/16 |
All, I had exactly the same symptoms years ago. I cleaned the carb
ports and it went away. On both carbs the main port and the idle port
looked PERFECTLY CLEAN when I took the carbs off but nonetheless the
problem went away when I blew them out.
A helpful mechanic at LEAF directed me down this solution path, by the
way. He even predicted that I would not see the obstruction in the ports.
Message 5
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| Subject: | Re: RotaxEngines-List Digest: 5 Msgs - 09/07/16 |
John, I hesitated to mention this because I had rough running issues at
high idle only after carb overhaul but not above high idle rpm. However
the principle seems to be the same for idle jet or larger jet. In essence
I got the same recommendation to blow out the idle jets from Lockwood,
including the comment that you may not see anything but blowing out the
jets is a typical first step with rough engine operation at the upper end
of idle range because fuel flow thru a very small jet with an undetected
restriction causes rough running at high idle before the next jet cuts in.
If the engine runs smoother when rpm is in the next jet operation range
then stick with blowing out the idle jet only.
Note that float bowls have a tendency to not seat perfectly allowing a
small amount of air to be sucked in during engine running which can result
in rough engine running too. Check for any fuel dampness under the float
bowl which would be an indication of a gasket leaking air in during
operation and maybe letting just a bit of fuel out when the engine is
stopped.
There have been gasket changes between float bowl and Bing carb housing
over the years. Some thicker gaskets than others ,,so it was suggested
that the thicker ones may seal better.
Note that rough operation can cause float needle valve to vibrate and
allow minor "flooding" possibly with evidence of fuel at the carb air
intake opening.
By the way I had my carbs overhauled the first time because they were many
years past the recommended time in service between overhauls and took the
plane immediately in its trailer to another state.The roughness showed up
right away so I ended up at another Rotax shop for another set of carb
overhauls including boil out of carb body. VERY shortly thereafter the
roughness returned. The second shop foreman suggested that I blow out the
idle jets. It seemed to work. My wings have been off for recover since
then so I have to be a bit guarded about that observation.
I also installed an extra fine gascolator screen as suggested by a Rotax
training guru at the second shop.
Oh, in case you my be wondering, the finger strainers in the fuel tank
pickups were clean as a whistle and the inline glass tube style filter
elements were clean as a whistle throughout all of this and I use a funnel
with a fine mesh screen to pass fuel into the gas tanks when fueling the
plane. However between overhauls I did change out the gas lines which were
well beyond the five year in service limit called for by Rotax.
OK enough rambling.
BJ Kitfox IV 1050, Rotax 912 80 hp.
> <jelling@newmexico.com>
>
> All, I had exactly the same symptoms years ago. I cleaned the carb
> ports and it went away. On both carbs the main port and the idle port
> looked PERFECTLY CLEAN when I took the carbs off but nonetheless the
> problem went away when I blew them out.
>
> A helpful mechanic at LEAF directed me down this solution path, by the
> way. He even predicted that I would not see the obstruction in the ports.
>
>
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