I have a 5 hp Robin engine, an EY20D, on a plate compactor. It starts up okay and runs alright with the air filter off but there is a large amount of white smoke coming out the breather tube. If I put the air cleaner on, then it blocks the blowby from venting and the engine starts to hesitate. I checked the breather assembly and can't seem to find a problem. Any other ideas before I break down and buy a new engine? Thanks.