SlowDriver

I've got that OS CV .15 engine that hasn't worked right since I got it. Pretty sure it's not a tuning issue, as I know how to tune. Rather I think it's an air leak based on other comments I've seen on the board.

I'd like to check for any air leaks to see if that's the problem before I chunk the engine.

1. Where are the most common leaks?
2. How do I seal them?
3. Is there anything else I should check while the engine's apart?

Also, could it be a backpressure problem? The pipe I'm currenty using is one that was very popular 3-4 years ago, cost about $20 and made a screamer out of a TRX .15 pro. I don't even remember what it's called or where I got it. I think some guy built them in his machine shop and sold them over the Internet. Great pipe, but not the best for my OS?

Rob6

Check the cooling head and header. Just titan the screws down if there loose.

murray.386

i dont have an OS but i did find that i had an air leak in my trx 2.5. the most obvious place for a leak wil be if you dont have the brass ring around the glo plug. the problem i had was that the heat shrink got put on wrong by one screw and let air leak as well. another thing to look for would be if there is fuel misting out of the engine somewhere. other than that just check seals. thats about the best that i can do hope it helps.

snoking16

between the cooling head and the engine there should be a ring/gasket. if its not there it could be leaking. well i think there is one. anyone know? i cant remeber right.

SlowDriver

No misting/leaking fuel on the engine that I've seen. It's not the glow plug. I'll try reseating the carb and check the cooling head gasket.

Should I get a new gasket even if there's already one there?

Also, any answers to my muffler question?