If rotor motors were dogged around town a lot, and only used the cheap gas, sometimes the motor would seize. Usually when you turned it off and you wouldn't even know it until the next time you went to start it. It would be seized solid as a rock. The Mazda fix...which worked fine... was to remove the starter, insert this tool, and force the engine over backwards. That would release the piece of carbon in the rotor chamber. Reinstall the starter and away you go. It did take this tool to turn the motor backwards. We've tried pushing the cars backwards, turning it backward with the front shaft bolt, or pushing forward in reverse. When the stuck...THEY STUCK! Its obvious how much leverage this tool has with its gear ratio. I only recall this happening to 4 or 5 in the 30 years I've been a dealer.

 

Bob Mears

Supermarine Spitfire