I have a YS 110 that I have had for about 18 months now. I don't get to fly much, and this engine has only seen about 8 to 10 tanks of fuel.

From day 1 it would not run right,, bog down and drip fuel constantly from the carb.
I got it back to YS, and those guys turned it around real quick, and it seemed to have the issues resolved, as I did a quick bench check, but only for a minute or two.
This is the first time I have run the engine since then, and now I have new problems. The engine when cold runs great, but as it warms up it gets sluggish, to the point it cuts out. When hot it will not restart either, and the only way I can keep it running is at full throttle for a short while. I have checked and double checked all my lines, and also when I release a line the pressure seems very high, I would say too high.
I have made sure that it is not run lean, in fact it is a little rich.
I am running it on Cool Power 15%.

Any Ideas?

The fuel is not the best for what you are doing, but that is not the whole problem. If you had issues with the engine from the beginning, WHY didn't you contact us? If it didn't run properly, it needs to be fixed so that it will.

Here's the address:

YS Service
1295 Industrial Court
Gardnerville, NV 89410

Phone 775-782-4562

Dave,

I did contact you, and sent the engine in. You resolved the leaking problems, If I remember right, it had to do with a seal or diaphgram not suitable for American fuels.
This is just the first time I have used the engine since then.

I will get the engine boxed up tonight, and sent back to you.

Thanks for the help.

I never see these engines as service is a separate business. It should never have gone back to you if it wasn't right. When you get it back this time, try running the recommended fuel YS 20/20 or Cool Power 30% heli fuel. It may solve a lot of the issues.

Dave,

I got the engine back, and have flown it about 6 times since. Apparently the head was not holding compression, so it was replaced.

Engine definitely runs a lot better, but now when its hot it won't idle.

Any ideas?

Paul

WHAT FUEL? PROP? PLUG?

Your weather is hot and humid now? Might be part of the problem.

Plug, OS#8
Fuel, Cool Power 30% Heli fuel
Prop, APC 14x8

I was running without the cowl, and the weather was not that hot, or that humid.

Try richening up the idle. Hot will make it leaner.

OS #8 or OS #F plug?

Dave can we run the 4 strokes on the #8 plug?

Allen

Tripp2loo you would like to to try with OS F plug or YS 4 plug instead of #8

Sorry I missed this one. The OS #8 plug will not work. YS #4 or OS type F only

I just double checked my plug selection, and its an OS, type F.
I use OS #8 in pretty much everything, except my Saito and this.

OK, so what's the verdict?

Remember I said I really don't get to fly much.. []

Not been out with it yet, should be in the next couple of weeks.
I will let you know.

OK, I'll be watching. Sometimes these threads get so long that I lose track of time

Uh, I hate to disagree with you Dave but... Cold weather will make it leaner, with hot making it richer. Air density and all those pesky details...

I won't argue that, but if the ENGINE is overly hot it will make the idle leaner. Maybe I should have clarified what I really meant. Not the weather being hot, but the engine.