I recently bought a house that has a 10' x 4.5' above ground pool that was installed in-ground. It has a Hayward Super II pump that had a replacement A.O. Smith 1hp motor that was having issues starting and then died. I got a new Hayward SPX1607Z1M 1hp motor to replace it. After the pump is on about 15 minutes the motor gets almost too hot to touch it. The water in the skimmer swirls strongly but doesn't appear to actually suck air in. The return line in the pool seems to be stronger than what the failing pump output before. The pressure gauge on the filter is reading about 15psi while it is running. It sounds like there is some air at the top of the filter while it is running. There is a very small amount of air in the basket of the pump while it runs. I don't think it is cavitating. I replaced the impeller when the old motor was still in as it was broke when I first tried running the equipment. The intake and return lines are 1.5" and the end of the return line has nothing to restrict flow.
Is the pump/motor too big for the lines? Should I get a smaller impeller? I haven't checked the voltage on the lines yet but will be.
Pictures of the pool and equipment can be seen here: Pool - Unclenard