Likewise welecome to the forum.

Ted is being too easy. More like smacking the back end with a 2x4. Not hard enough to dent it though.

Check this thread to which I just posted:
http://www.poolforum.com/pf2/showthread.php?t=9444

As Ted said, probably the switch contacts are crummy. The fact that it does start says the starter winding and the capacitor are OK. There are two kinds of hums. The really loud hum says the starter winding is powered and pulling a lot of current. Probably a shorted cap. A lower level hum, which will still trip a breaker, says the starter circuit is open, and in your case, crummy switch contacts. See if this helps and we'll pursue it further if needed.
Al