Sounds like the centrifugal starter switch is crummy. Check this thread:
http://www.poolforum.com/pf2/showthread.php?t=4800
The 2x4 method referred to is the trick of whacking the side of the motor with a 2x4 with power on and it doesn't start, not hard enough to dent but the shock will sometimes cause the starter switch contacts to connect. You need to clean the contacts with fine sandpaper or a small flat file. Use something like 400 or 600 grid Wet-or-Dry (auto stores) and lightly dress the contacts. The thermal cutout switch is what is kicking out when it doesn;t start. It's the thing at top-middle of the pic just over the horizontal gray spring.
Hope this helps.
Al
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