Will start and run for 15 minutes then dies...will restart but will just idle...if you turn it off for 15 minutes it will restart and run for 15 minutes then dies again...any idea of what might be going on?

 

The first thing I would check is a restriction in the tank vent. It allows air to enter the tank to replace the volume of fuel burned. When it starts to stall, loosen the gas cap and see if that corrects the problem.

The other possibility that struck me was an intermittent temperature related failure of something electronic, but I'd start with the simplest possibilities first.