I sold this mower last month and it was returned yesterday. They said it was used twice and now won't start. There is excellent spark and the carburetor is new and has since been cleaned. If I hold my finger over the spark plug hole there seems to be very good compression and suction. I don't have a compression tester or leak down thingy. The PCV valve does not appear to be blocked as there is no sign of oil in the return pipe. I have primed it with fuel and on rare occasions it will try and start with backfiring and chugging but never full roar running. I think I will junk this engine as I feel there is something wrong inside, perhaps timing, but before I do I wonder if anyone had any ideas. I am thinking of pulling off the exhaust to see of it is blocked but that is just my clutching at straws I think.
