I have a 2002 John Deere X475 with a 23 horse liquid cooled kawasaki engine. My problem is it starts up fine and I can mow the yard for about a half hour... then out of nowhere it dies. So I let it sit for about 15-20 minutes and start it up again, and after about 5 minutes it dies again. We have fuel spark, a new thermostat and rotation of the engine but it still does not fire. After waiting about a 1/2 hour to an hour I try again and the process repeats itself. What could possibly be wrong with my mower?

Check fuel cap for venting.
Check fuel lines from tank to pump , look for a kink.
Luck