If it has some kind of variable resister for the speed control that could also be bad. If it's a belt driven it could be you need to tighten or replace the belt.
This is a belt driven unit. When we broke it down, I was able to turn the bearing with my finger but it was not very smooth. The belts are worn but don't seem to be cracked. The motor runs fine and everything else seems structurally sound, just old.
Now for the fun part. We just purchased this used from a fellow who was selling his deceased fathers old honey house equipment. When this was stored 20 plus years ago, it was put away with about 100lbs of honey in the extractor and another 200 or so in a storage tank. I know that honey doesn't go bad, but the local critters had found the extractor as a great place to winter. Rat nests, nuts, seeds, the works...a buffet for vermin. $25 dollars in quarters at the local wash plus 6 hours of elbow grease has the other 2 tanks, clarifiers and uncapping table looking pretty darn good. The only problem is my wife knows my old football injuries wont keep me from using Comet if I really want to.
So, my wife and I are restoring this to get it operational so we can replace the 4 frame tang we currently use. Kind of a big jump in equipment to go from a 4 frame tank and 5 gallon buckets to a 1000lb and 3500lb holding tank and all the other goodies, but hey....we have BIG plans lol.