Hi,
I have similar problems with the induction motor from the dryer in my washing machine.
About once a year i have to disassemble the motor, clean off all the dried up grease and dirt, recoat the bearings with a very light coating of high temperature grease and then reassemble, it'll then work work fine for another year.
Unless the windings are clearly burnt there isnt much that can go wrong with an induction motor, try stripping it and giving it a thourough clean.