Chainsaw Repair

Hey so I just picked up a Pioneer P41 that was at an estate sale for $10. I really like the saw so I cleaned the carb and got it started today but theres a problem. I can't seem to tune the thing like it idles really high and if I turn it down it will just die but I can hold the gas and it will rev up but its reving up with like a slight bog. So it won't rev up all the way and it won't cut anything. I tried to cut some logs I had laying around and it would cut them at all and the chain is pretty much brand new so I have no idea whats wrong. The chain doesn't get stuck in the log it keeps spinning so I don't think its the clutch but idk. The only problem that I can spot is the fact that it has a black rubber O ring on the gas cap when it should be a cork O ring which might be causing it to lean out idk. And yes I tried putting both the high and low to one turn out but no matter what I put the screws on the thing idles terribly and will spin the chain because its idling so high.

adjust your L screw about 1-1/4 turn out and H around 1-turn out   

The fuel lines and tank were actually perfect but I flushed the tank and lines anyways.

Ok thanks for your reply but 1. Its not the carb. 2. I'm fairly sure its the head gasket. 3. Its impossible to tune but the thing runs so its not a typical fuel issue.

So yea I'm pretty sure its the head gasket having a leak thats letting in air which means that this saw is going to become a parts saw unless I can find a new head gasket.

The cylinder and head are one piece, no gasket. It sounds like an air leak, the best way to check it is with a pressure/vacuum tester which would pinpoint leaking crank seals, cylinder base gasket, intake gaskets. Check the insulator block behind the carburetor for cracks or warpage.