I am not accustomed to repairing floor furnaces, but the customer is poor. Normally I just replace them. Anyways I replaced the thermocouple, pulled the burner assembly out and cleaned it out. I put it all back together and there is a weird problem. After the burner comes on, it will stay on for a while and then it go off all by itself. I need some old school advice here, like I said I normally work on new stuff. I looked in my schoolbooks for gas heating and didnt find my answer.