| I wish to express great sympathies...I'm still fighting the same
thing on my OS .25. Last week we found some junk in the tank,
and I cleaned the whole mess out; still the same symptoms.
I wouldn't have replied to this one, just sort of sit back and
watch the suggestions come in, but THIS week I had someone who
knows engines look at mine. Well, the diagnosis was the same as
.1 said, too lean. He found air bubbles in the fuel line. I
took the whole thing out; getting pretty good at it now. I think
that the intake line, on the inside of the tank wasn't on the
brass tubing far enough. It was only on about 1/4 inch, and I
suspect it should've been on more like 1/2 inch. So I replaced
the brass part, made it a little longer and put the thing
together again. Last nite when I ran it up it sounded good, so
we shall see next week.
This problem is doing some serious cutting into my lesson time.
It seems to consistently cut out about 4-5 minutes into the run;
just enough for the instructor to trim the plane out and get
ready to hand it to me. I haven't been able to get the stick
time so far. Every landing has been Dead Stick!
If the fuel line fix doesn't get it I think my next move will be
to replace the gasket on the engine backplate. It has some
suspicious bubbles around it when the engine is running. Can
someone tell me what that material is? I'll have to make a new
gasket. After that, I'll retire the engine from this plane and
put my K&B .20 in there. Been reluctant to do this because the
K&B is a heavy engine, and I'll have to add some tail weight to
get the plane to balance right.
No offers on the OS please, if I take it out of the Eaglet, I'll
get someone to fix it for me and put it in something else.
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If your plane doesn't need every ounce of power, try running very
rich (mostly 4-stroking, fuel spitting out muffler). If it will
idle that way, try several flights and if it's ok you were too lean.
Then you can gradually lean out to proper setting. I always try
to start pretty rich because the mixture will lean out when your
fuel tank gets low or the plane is in a nose-high attitude.
One thing to watch out for is when you run too rich the
engine tends to load up while idling. If you go quickly to full
throttle it can quit, which can cause problems for aborted landings.
Bill
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| Frank, just cleaning up my notes and I came across this one...the
problem turned out to be that the screw holes on the carb did not
line up with the holes on the engine. So when you screwed the
carb in it was not seated tightly against the engine body, and
the engine was sucking air through the opening.
Took a long time to figure that out -- from the time I bought the
engine from you to this last February or so. Anyway, I put a
brass shim in to take up the slack and the engine's run fine
since. In fact, since the demise of the Eaglet, its been my
primary engine.
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