[Cajundaddy]

Sounds like possibly a mismatch between motor and impeller causing the motor to draw too much current. Motor rated HP is ridiculous these days and about the same as wattage ratings on amplifiers. A Super II pump is an up-rated design and if you have an up-rated 1hp motor on a full rated 1hp impeller the motor will trip the thermal switch. Maybe time to go back to square one and verify the motor and impeller "full rating" to be sure they match. You can also test this by checking AC voltage and current while under load to see if current draw is above the rating on the motor label.

The other possible problem is if the diffuser is worn out and the impeller is dragging under load. You should hear that though. My guess is you need to downsize the impeller to match the motor and all will be well again.