I need some electrical debugging help:

I have a 2 HP 220V pump for my lawn irrigation system. I pull water out of a lake. The system is 15 years old and I am having a problem this season. The timer starts the pump, the pump gets power for a few seconds and then trips the 30 Amp breaker. I pulled the pump into my shop and verified that the motor is not bound up (I could turn the shaft with a screwdriver). One of the two hot wires possibly had a very small cut in the insulation where it passes through a hole in the motor, so I fixed that. Pulled the covers off of the large capacitors (I assume they are capacitors) on top of the pump. No signs of burning or other problems. Reinstalled the pump and get same result.

Anyone care to offer de-bugging advice? How do you test the capacitors? I think at least one of them is a jump start capacitor to help the pump overcome start-up load. I have a volt-ohmmeter, but only know the basics of electrical debugging.

You may be concluding (correctly) I know enough to be dangerous, so I treat this 220V appliance with great respect.

Thanks in advance.