I have a coleman oil furnace 1991 in my mobile home.I run kerosene only . Problem is,after furnace has been off for a while due to temp being reached,whether 15 minutes or 2 hours when air temp reaches min temp and burner kicks on, burner will work,then after few minutes,maybe 2 or 3, burner shuts off and fan turns on,which circulates the hot air throughout the house,which is normal but I get a burning smell when fan kicks on,the blower stays on while burner kicks on and off until temp reached then blower runs for a minute or two to cool down then unit shuts off,again seems to be normal, and also I have had my nose inches from fan electric motor and that doesn't smell.the burning smell doesn't come back at all while the furnace is running,just the first time the blower turns on after furnace has been off,after the first cycle of burner, any ideas? Need more info?

Call a heating professional and have a ON SITE inspection of the furnace heat exchanger. The life you save may be your own.