Reply by THOMRIDER

well i had the same thing happen to my pool filter motor and it was blown bearings in the rear, causing the magneto to stick to the surrounding magnets and not spin freely hence a buzzing sound, when this happen to me it was more expensive to have it rebuilt than to buy a new one. My motor was a 1.5 hp and I got a 2hp for less than rebuilding the old one. I went to Grainger they had the best price.

If you need any further help let me know.

-- Its all about the jigs