While using the tractor it just slowly stopped. It turns over but does not start. Yes it has gas and oil and the air filter is clean. What do I check next?

Bluemm

Verify that you have gas making it into the engine through the carb. Could be a plugged fuel filter if your mower has one. Verify that you have spark. Could be a bad spark plug or coil.

MOWERMAN2468

are you referring to the tractor's ground travel coming to a slow stop, or the engine slowly stopped? did you smell anything like rubber burning? if so check the belts and pulleys, they could be off track and causing an excessive load on the engine, and prevent it from starting. but i really need more info. here.