Starter keeps starting!...

The solenoid in those starters is a magnetic throw that pulls the contactor against 2 terminals that competes the circuit to the wound motor. The contactor is on a fork that shoots the pinion out to the convertor/flywheel teeth. If there is no spring in the solenoid it may stick. There should be a good amount of resistance when you try and pry out the pinion gear from the idle position. It will snap back in. I think you can test it if you remove the wound motor lead from the solenoid. Just use some jumper cables: clip onto body and clip onto battery lug and then hit the battery terminals. Should hear a nice sharp click and see the pinion shoot out and it shoud return Just as fast with no voltage. That is weird