I have one on a World Models Fun World 3D. It has amazing power for a gas engine its size. It will hover the airplane and go vertical forever. The only problem I ever had was the spark plug cap. It became loose and caused the engine to misfire. I used a small hose clamp on the cap and haven't had any problems since. It is a very nice engine. I believe your friend should call RC Showcase and discuss the problem with them.

FWIW, Brian.......