Small Engines (Lawn Mowers, etc.): craftsman mower, valve job, intake valves

Question
I have a mower with a 15.5 kohler when mowing it will quit after mowing about 10-15 min.does not sputter or miss will not restart let set for 30-40 min will start back and run another 10-15 min. then quit again any suggestions  

Answer
Ed
What it sounds like is the intake valves may be the problem. When the engine gets hot they will expand and after a while the will expand and will start to leak not letting the fuel pressure get low. You may have to see about getting a valve job.
Thanks