Last night I smelled something burning from my furnace. It smelled like a motor. I am 90% sure it's the exhaust motor. After letting it sit for a while (reminded that it is 0 degress out) It worked fine for a couple minutes, then it kicked out before the thermostat was satisfied. I blew off the motor and then put wd-40 on the bushing (not bearing) that the shaft spun on. It continued after that to work fine and I noticed I had pushed the shaft in a little as I oiled it. Now there was no noise or wobble (that I could see) suggesting the bushing is bad. Could it have been the play in the shaft causing this? If so, Is this normal? Or should it be replaced. It has since worked fine and has stayed running longer than normal because of the cold snap we are in? The motor was not really dusty. The Furnace is a Tempstar. The motor number is 7021-9335. Since there is many different numbers for the replacement part, I figured it would be easier to give original part number. This furnace is approx. 12 years old.