D185q will not run for long

I have a Sullivan d185q with a John Deere motor in it. On a cold start it cranks and runs fine, but after about 10-20 mins of running it shuts off and will not run until it cools down. It will crank and run if I'm holding the starting aid button but the second I let it go it dies again. I've also noticed when I use too much compressed air for a long period of time it shuts off and refuses to run again.h