2 Capacitor induction motor Humming troubleshooting
If the centrifugal switch is OPEN when at rest, that's your problem. It should be CLOSED at rest and OPEN when at 80% speed.

When you stall and try to keep using a single phase capacitor-start motor, it slows down, then the centrifugal switch re-closes, putting the start winding and cap back into the circuit. But that winding is not designed to be used under load, neither is the centrifugal switch. You burned out the switch, maybe the winding insulation too.