IT just be the dust
Or it could be your starting capacitor has left the building. A high pressure air hose on one end and a shop vac on the other end of the motor is the first thing I'd try....it don't work now so what's to lose?
Those motors are a pita to remove, being hard wired to the switch and all, so if the capacitor is accessible from and end cap that's great. Otherwise it's a trip to the electrical motor repair center, unless you are familiar with the dis-assembly proceedure....JMO bill
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)