Set timer to spin and check vac at timer, bu to w/bk. Also check rd to yl. This is vac to your motor, run and start windings. If it hums but wont start you probably have a problem with the start circuit, so you are talking timer, motor or capacitor. If you have 120 vac on both of these combinations you can check at motor from rd on motor itself to each side of the cap, you should see 120 vac on each but if you have 0 vac on one end you have a bad cap, this is assuming you have 120 vac out of timer rd to yl. Let us know your readings when you get a chance.