The start capacitor is easy to change out. Do that first, watching the value marked on the old one. They
can be bad right out of the box. Keep that in mind.
But be aware the start switch is more likely. For that you will find it necessary to(at least
partially) disassemble the motor. And watch out for the wires so they don't come in contact with the mechanical parts as you reassemble it. The start switch is
usually on the opposite end of the fan. Make a witness mark (with a center punch?) so the end bell can be replaced where is was originaly.
Do not use a file or sandpaper. The contact should be well polished.
While you have it apart, check that everything is loose and clean inside. Don't use
high pressure air, stay below 25 or so pounds. It shouldn't smell burnt, but that is subjective. Prior experience pays off big here. The big issue is chips and possibly sawdust. There shouldn't be
any. Use a small paint brush to dislodge any the air doesn't get.
As you reassemble, the frame bolts will affect the rotor spinning. Tighten up all around and spin the shaft. Then keep tightening individually 'til it is spins freely as possible. Sometimes a rubber hammer helps when seating an end bell.
If a ball bearing motor, it's a good one. But unlikely for fractional horsepower these days. Unless the rotor moves enough to come in contact with the pole pieces, don't worry about it. Just keep it lubed.
Shim washers on the shaft are important. Keep trach of which end they came from so you can replace them where they belong. Sometimes they are fiber, be careful with those, they are very brittle.
Bill Hudson
