Originally Posted by rufusswan
The starter motor is grounded when bolted to the motor case. So clip a wire to your battery neg on the bench and hot to the post and the motor will spin. That part of the starter is pretty brain dead. Take apart the solenoid and clean up all the connections inside as they can get dirty and built up with carbon. Clean and lub appropriate parts and bench test the unit as a whole.
Then you can decide if/what needs replacing.
Sounds good. Snowbum made it sound like taking apart the solenoid was hard? Maybe I need to reread. What is the other spade lead on the solenoid do?