Most likely, it is the motor. Two kinds -- repulsion start, induction
run. Starting winding is burnt out. The other type is a capacitor
start motor with a centrifugal switch. These types can be spotted with
a "can" on the side of the motor. In the first instance, the motor has
to be replaced. In the second case, the capacitor can be replaced.
Pull the motor and take it to a good motor repair shop. They should
either be able to repair it, or sell you a new one. If it is the
repulsion start - induction run type, then it is not usually worth
repairing. You should be able to get a replacement motor from your
parts distributor or dealer. About an hour's job, maybe, to pull it,
and replace it. PITA job. Wiring issues, as usual -- disconnect.