Condenser fan start capacitor is bad. Look for oil that has leaked out of it. That is a sure sign.

I just had the same problem. I replaced the motor with no luck. It turned out to be a bad capacitor. If it is a dual capacitor, three prongs on top, it also starts the compressor. It is recommended to replace the capacitor anytime you replace a motor. I would try replacing the capacitor first. It is a lot cheaper that a new motor. If that does not fix the problem then you can get a motor. No harm, no foul. The slow start of the motor is a common symptom of a bad capacitor. The motor is not getting enough voltage. The capacitor increases the voltage like a transformer. It will boost it to almost 400 volts, depending on your unit.