It's not necessarily that the motor needs to be re-wired, and in fact that's not what it sounds like at this point; if you're having a problem turning the machine over by hand, that indicates some type of physical obstruction and not an electrical problem. But you'll most likely need to open the motor up to find out what it is. The tutorial I've prepared on the blog should give you enough background to pull it off, and with any luck it will be something simple.