I have a craftsman lawn tractor model 917.271635 16.5 hp 42 inch deck. It stalls after it seems to run great for 30 min. After it sits for 5 to 10 minutes it runs great again for another 15 minutes than stalls again. I changed the oil, replaced the fuel filter. What could the problem be?

Junk in the fuel line, carb or gas tank.

Or your coil could be beginning to break down.