Thanks for the responses so far. I pulled off the exhaust and the piston looked alright to me but I'm no expert so I will post up the pics. Today I mowed a fairly large section of the lawn with it. It started first pull but what I found was it didn't want to run in the run position (choke off) so I had to cut the grass with it in the choke position the whole time. After about half an hour it cut out when i hit a section of long grass and i had no luck starting it back up.
