It is possible to over oil a motor. If the problem started after oiling the motor, I think you know what happened.
There are other causes, such as a high content of dust in the coal, especially wet coal. Did you just get a coal delivery? Use the crank to turn the worm by hand. Is there any strong resistance to turning?
Did you install new coal pipes recently? Is the feed worm more than 3-4 inches inside the coal bin? Is this a sudden problem? Is the dust cover installed on the motor?
Does the worm have any sharp edges? Scrape out the coal and look into the bottom of the pot. Is the voltage to the motor close to 120V?
I would say at 24 years an investment in a spare would be a good bet after you have verified the items suggested by stoker-man. That way you could install the new one and remove the old one for disassembly cleaning and testing to make sure it is good. Your local electric motor rebuilder or supply house should be able to test the old one to see if it is a viable spare unit. Remember units never fail when you don't need them.
Here are the 3 oil ports. Two are in the connecting rod and one is in the clutch assembly. Add a drop to each end of the connecting rod, a few times a year and a few drops in the clutch assembly. In the top picture, the oil port is located in the center, to the left of the gear and also on the right bottom side at the top of the connecting rod.
yes, your motor owes you nothing. Order a motor from Grainger. It's an AO Smith, Grainger part # 4MAO ??, don't remember the last number, maybe 8 or 10. Be sure to install the dust cover, supplied with it. 1/8 HP.
Thanks for that info I called Grainger and they have an AOSmith #4MA1O 1/8 hp but He's calling it an oil burner motor My local supplier has a 1/8hp marathon motor also calling it an oil burner motor neither one knows of a cover Will either of these work???