[floyd]

Always make sure the head bolts are tight. I've had a few of my own 120's with loose head bolts when I checked them. I've used some blue Loctite to keep them tight. Cheers Floyd

[Youngguy]

Originally Posted by volksman

No not this particular engine. Rcexl 1/4 32 spark plug with your same set up. Will give better combustion of fuel. Can run leaner. Something simple as a gasket leak introducing air can cause rough idle transition etc with out flame out all the time..70 dollars and about an hr would install it

I have and it works well as I indicated in a earlier post. Tried it with both a gasoline Walbro carb and the standard OS carb. Ended up using the OS carb with my own fuel mixture of methanol and 10% Koliz oil (don't need nitro with ignition). Used this engine and fuel combination for years in a 88" spitfire flying it in Scale Masters competitions. Very reliable with a good idle and mid range.

[Raptor30V2]

Could be bad bearings that will put the flame out. If you notice any rattle or you need to run richer to keep temp down it is most certainly the bearings.