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Surging engine

I went out to fly yesterday and was using my fairly new Evo 46 engine. For some reason when I got to full throttle the engine would surge and then almost die. I tried to figure out what the problem was but it seemed to go away while I was diagnosing it. It was colder than usual, but only in the 50s. I was trying to see if maybe there was a pinhole leak in the fuel line but then the problem went away and didn't resurface.

Any ideas? I'd rather figure out what the problem was than hope it doesn't come back.

Thanks, Steve

Reply to
Steve
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My guess would be either fuel foaming, or a particle in the fuel tank that intermittently gets sucked onto the fuel pickup. Or is your servo linkage surging back and forth?

Reply to
Robert Reynolds

Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

Also check the throttle servo screws. Make sure they haven't loosened up. I had that happen on one plane. Drove me and several "gurus" nuts until a newbie said "Is the servo supposed to move around like that ?" - from the mouth of babies. {:-)

Reply to
Ted Campanelli

It was leaning out. That could indicate an obstruction in the fuel system. It could've been as simple as a needle adjustment (richer).

Reply to
mkirsch1

I didn't notice any movement of the servo, but I wasn't especially looking either. I think I'm going to go with a particle in the fuel tank. Sounds like it's time to pull the tank and tear it down and see if I can get it cleaned up. I can also check the servo while I'm in there.

The Evo engine sure starts and adjusts easily, but I wonder if the ease of adjustment leads to some over-tinkering of the needles...

Thanks, Steve

Reply to
Steve

If you have a brass tube in the tank, check to see if it is leaking air.... fuel eventually will corrode the tube and cause minor air leaks that can make the engine run erratically and keep you from completely emptying the tank at the end of the day.

Actually, that was how I found my tube did have an air leak. I could not pump it dry when it was time to go home.

az21 .

Reply to
az21

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