Thanks for the reply. When it initially started happening it was the fall and cool out. I live in New England. I put a new carb in and it's in the garage while I work on it. Appreciate the advice on cool down though.
I have a Craftsman lawn tractor with a Kohler CV16S engine. The original symptoms were that it would start to stall after running for a while but only up hill. Then it started doing it a little if I hit a bump just right. Long story short I replaced the carb and tuned the idle speed and idle...