If you power up the motor with the whole pump assembly removed, does it THEN spin? (with a clamp-on meter check the amperage draw--should be less than rated because it has no load). If so, it's the bearing in the pump, which is what it sounds like.
But it's possible the motor was damaged--if it doesn't run properly when powered up without the pump, then I'd consider replacing it all. Seems to me, if the motor is bad but the pump is OK, replace the motor. If the pump needs work but the motor's ok, fix the pump. But if both are shot, IMHO, I'd go for new.
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