Okay kids, take it easy on me - I'm still a rookie:
I would initially suspect lube trouble; barring that I'd double check my alignment and torque values (this is assuming I've checked the manual to be sure I'm using the correct starter [parts ordered/delivered may not be correct])...
If I'm doing everything right there--then I probably need to back up and look for an electical problem with damaged wiring, poor connections, voltage regulation or a faulty generator. I would also check the clearances on my cranking shaft just to be sure there isn't a wear problem tearing up the component.
Starters shouldn't burn up with any noticeable regularity...this is just what I would do to find my culprit. Be kind if I'm wrong.
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Patience is letting your motor idle when you feel like stripping your gears.