scoli121

My Feedback: (20)

I just started the first four stroke I've ever owned. The engine, a OS FS70 is mounted in a U-Can-Do 46 that I just built (99% finished). When I ran the engine, only about a half tank, the plane vibrated so much that it almost hurt to hold on to it. It wasn't severe enough to make the plane move or anything, but it was very high pitched vibration... almost like it could make your spine raddle. Is that normal??? It feels like it could shake the whole plane apart. Also, it stalled after approximately 5 min, and was so HOT!!! is that normal either? Am I missing something here? Like I said, this is my first four stroke, and don't know a lot about them. I've been handling two strokes for 20 years, and can't remember anything like this... Help anyone???

MHall

My Feedback: (7)

I would think that due to your long years of two stroke flying that tuning would obvious for you, so my next question would be was the plane assembled when you ran the engine(wings on)? The wings help damped the vibration of a four stroke. As for the heat, it sounds like it was lean, that would also cause it to hit so hard to shake the plane. I hope that the prop and spinner were balanced too. [8D]

SENZA

I agree you are running to lean, they will shake hard when leaned out

scoli121

My Feedback: (20)

Well, yes... lean would explain the heat I guess. I was actually running through the 'break in procedures' going back and forth between rich and lean. Now that I think about it, I think the prop and spinner balancing probably had a lot to do with it. It was pretty difficult getting the prop and spinner to fit on the engine.

skythumbs

Four strokes hate to be lean and it will damage you new motor. Make sure the prop is balanced properly.

Spaceclam

balance your prop and spinner and try again. you may have been going rich/lean but were you the right number of clicks out?

scoli121

My Feedback: (20)

by "the right number of clicks out" did you mean 'too lean', or 'too rich'?

Spaceclam

the manual says something like 2.5turns out or 1.5 turns out to start. could it be that it said 2.5 and he was only at 1.5?