Small Engines (Lawn Mowers, etc.): lawn tractor that stalls out, sears craftman, craftman lawn tractor

Question
I have a sears craftman lawn tractor 15 HP,(2003 model) that starts up and runs fine for about 5-6 mins....then starts backfiring and running rough....then after a min. or two of that, stalls out and won't restart, until cold again....any ideas what the problem is?...it has fresh gas, it was doing this at the end of last season, but i just checked today and it is still stalling out after 5 mins. or so

Answer
It sounds as though a couple of problems could be present.  First, try loosening the fuel cap when it tries to stall.  There could be an issue with the tank vent.  It could also be a problem with incorrect valve lash clearance.  This would allow a valve to hang open slightly once the engine fully warms up.  Another problem could be, if equipped, the anti-backfire solenoid in the carburetor.  This cuts off fuel when the key is switched to off to prevent a backfire but could also cut off fuel (even partially) if it has a problem...check with a dealer for recalls or service bulletins for this particular problem.  Hope this helps.