Try this to see where the problem is: remove the belt. Disconnect the capacitor and jumper the two leads together that went to the capacitor. Try to start the motor. It should start, but it may start slowly and without a lot of torque. If it starts, then the internal switch and mechanism are good and you have a bad starting capacitor. If it still won't start, then the internal switch is either bad or has sawdust in between the contacts.
Starting capacitors on dual voltage motors are generally rated at around 125 V (because the starting winding will only see 125 V regardless of the voltage that the motor is connected for). A ballpark for MFD rating is approx. 200 MFD per horsepower for a 3450 rpm motor.