Bench testing a 1932 - 1939 starter motor

[Bob Culver]

Is is the accel wot matters rather than speed. The starter accelerates violently and needs be held in a vice. The spring clip which lightly grips the pinion is critical; if too tight pinion will not engage and if too loose will not retain pinion. It will then drift into mesh and then so violently out of that the process often repeats a few times before it chances to return sufficiently gently not to rebound. Curious and puzzling sound effects.  When the engine fires the overrunning  returns the pinion but not too forcefully. (written before others appeared)