New pump, or just new motor?

I have a Dura Glas 1 1/2 HP pump that I believe is 20 years old. It is shot, so the question is, do I replace the whole pump/filter unit? Has there been efficiencies in design that are worth it, or should I just replace the motor. I have taken the pump apart and the impeller appears to be solid, as does the the rest of the filter portion of the pump.

I also have a question on the 2 phase pumps/motors as that appears to be the way to go. How do these exactly work? Is there a 3 way type switch that needs to be installed, off, low, and high? Thanks, and I look forward to your insight.

The newer motors have a better power factor (PF on the motor name plate) are are more efficent than some older motors. The closer the PF is to 1 the more efficient the motor.

Most two speed motors have a switch on the motor to change from hi to low speed but these wires can be extended to a switch or time clock if desired.

So do think that if the rest of the filter portion is in good shape then I should just get a new motor?

Usually the biggest problem is getting the whole thing apart to replace the motor and then finding the parts to put it back together again.

If you have all the seals and gaskets you need to put it all back together and you are satisfied that the pump screen assembly is in good shape then a motor only is the way to go.

Motors are paired with impellers so if you replace the motor, you must use exact braking HP to determine the replacement (HP * SF). Otherwise, the motor could be overloaded or underloaded.

Also, because the rest of the parts are 20 years old and probably need replacement as well, if it were me, I would replace the entire pump.