I have a Jacuzzi spa pump model s55cxnfe-7055. When the pump turns on it hums for a few seconds then turns off. I turned the shaft using a flat head screw driver to spin the shaft right and left with no resistance. When I turned the breaker on, the motor hums but this time I tried to spin the shaft right when it turned on to help it self start. however when I did this I noticed the shaft would not spin at all. It was locked up. Any ideas?