Same problem - mower was dragged out last weekend having done last year successfully but now would not start.
Again I pulled the carb apart and blew out the jets. On reassembly it started first pull but only ran for some 15 seconds and then stopped. It will restart a few minutes later, on choke, and run for another 15 seconds and stop.
It seems the filler cap vent solution was a red herring.
I am convinced it is something to do with the vacuum control on the throttle rather than fuel delivery....
Anyone got any thoughts on this? There are numerous instances of this fault on many forums - someone MUST know what is causing this is.
ZZ_von_Schnerk
May 2008