Small Engines (Lawn Mowers, etc.): john Deere 345, john deere 345, gas tank

Question
My John Deere 345 with a 20 hp liquid cooled Kawasaki starts great and runs and mows for an hour (sometimes less)or so and stalls. It will start again after a few minutes and run for a couple more minutes before stalling again. I can feather the chole to keep it going for a chort time but it ultimately quits totally.  A few minutes later it will start and run for another while. I have changed oil, plugs, fuel filter, air filter looks clean, coolant is full. Just wont keep running. Feels like it is not getting fuel.
Any ideas what is going on?
Thanks,
Greg

Answer
Hello Greg:

A Bad Fuel Pump, Gas Tank Cap Not Venting Properly and the Valves May Require Adjustment. I Suggest you Check the Gas Tank Cap First, then the Fuel Pump and then the Valves. The Engine Running for 45min to and Hour Indicates a Vacuum Building in the Tank and Restricting the Gas Flow or the Fuel Pump Heating Up and Losing Pressure or the Valves Heating and Expanding Causing the Valves not to Seat Properly. You can View a Breakdown/IPL of the Mower at this Site Addy, http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.H... and Enter the Model Numbers and Click Find. Then Select the Sectional File. Then Select the Section of the Mower you Wish to View Online. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John