I bought a JS28 two summers ago and only used it one time then it sat all last year. When I tried to start it this year it was very hard to start. Finally did get it running and used on a very small yard. About 15 minutes of mowing. The next time I tried to start it, it hit on first pull and ran about two seconds the died. I took it apart and checked the springs on the auto choke system and such. Put back together and it hit on first pull but didn't start. Every pull after that it doesn't even try to start. Made sure the kill switch is open. Cleaned the carb bowl. Was as new. Nothing. What am I missing? Any help would be appreciated. Thanks. Tim