If the engine has a lot of resistance to turning, the load on the starter armature can prevent the solenoid spring from disengaging the starter drive unless the engine starts and unloads the gear. Also, a broken or missing return spring in the solenoid can cause the same problem.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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