I replaced my Sta Rite Max E Pro pump motor with a new 1.5 HP 56Y Century motor wired for 240 V and flipped the switch and it hums but does not rotate. Used a volt meter to confirm that I am getting 237 volts to the motor. When I replaced the pump seal and impeller I hand tightened the impeller but noticed it was difficult to spin the motor afterwards. Is it possible that the impeller is too tight? If so, how do you tell how tight it should be. I plan to disassemble the pump (again) today and see if I can get the motor to run without the impeller. My old motor and this new motor are identical and do not have a centrifical switch that I can see in the end bell? What device switches off the capacitor after the motor starts? Any help would be appreciated, thank you.