Hi, Just bought this motor non running. I turned it over by hand and sometimes it turns over OK, but sometimes it has a real rubbery feeling resistance. It makes kind of a rubbery noise when turning the flywheel. the rubbery noise is coming from the bottom of the powerhead, where it meets the exhaust housing. It will how soo much resistance to where it wont turn over. you have to work it back and forth to get it to turn over. The couple times it turned over good, I checked the compression and it turned out good. Anyone have any idea what would be causing this? Thank you