2016 Memorial Day.

Turned on the pump and hummmm - no rotation. Loosened the mounting bolts, flipped the switch and it came on. Reassembled.

I let the pump run for two days circulating water to oxidize some nasty squirrel and salamander carcasses.

Charged the filter and vacuumed. Pressure spiked to 40 pisg, so I back rinsed, flushed, wasted, back flushed, flipping the switch many times for each change in operation.

Then the motor stopped coming on. Eventually I gave up. Next day it came on but would run for 10 seconds and trip the main.

After going in the basement to set the breaker about 10 times I ruled the motor dead.

Next day I switched the motor since I had a new Dayton motor in storage. All is good - but.

The Dayton motor diameter is less than the AO Smith I replaced. There is a small space under the motor case.

Dayton motor case is very hot to the touch. Too hot to hold for more than 1 second.

Mechanically & electrically everything is good. AFAICT.

Why is that case so hot?

Looking for troubleshooting options.