Well I stupidly stripped the threads on my OS .91FS while changing glow plugs today. Anyone have a head or a bad engine with a good head they wanna part with??[:@][:@] If any of you moderators know of a better place to pose this question and get a better response please let me know. I know lots of guys here fly with OS .91FS engines so I figure this is a good place to start.

I remember seeing this replacement head called the Viper. It had holes for two glow plugs! This is supposed to mean you have smoother running because of two glow plugs giving a more constant mixture setting or summat. It was desinged for an OS 91 I thinks. It may have been for heli pilots but I have no idea.

Hope its sorted out soon anyway. I know what its like to have no planes right now.....

i think it was the ys 91 two stroke it was designed for

YS make two strokes? Interesting. Well yep thinking about it it did look like two stroker head.

nonono. Viper head is for helis and its for all 91 size 2 strokers

YS only make the 45 and 91 2 stroke HELI engines.

then engines hees asking about is the 4 stroke

Yep I realised that. Still, very snazzy head. Bit pricy tho.

Drill out the stipped hole to a size bigger. Plug it with some aluminum. Drill it and tap it again. Any good machine shop can do this for you. I would have them tig weld the aluminum plug in so it don't leak though. My .01 worth. I'm a tool maker. I've gotten motor for nothing cuz of this problem. I take them to work. fix them and run them. hahahahah