I am by no means an expert; I have had my leg off 3 times (same motor) , is the key in the drive shaft for the impeller? are the two water tubes mating up to the impeller ports properly with the rubber grommets/seals? I use aviation form a gasket to mate the impeller stainless plate to the leg body and to mate the impeller housing to the stainless plate (so both sides). Is the new thermostat opening? remove the thermostat and see if water spurts out of the two ports when re-assembled; there could be many things going on there.
My water pump two port seals are well past the expire by date as well as the pump components except for the impeller, it's new. I form a gasket the "hell" outa anything that required a seal and when the motor is running it's quite cool. I run it in a tank and have found that an air lock can happen and the pump fails, I turn the motor off and let the water settle and let er rip again, too much turbulence in the tank caused this "no pumping" for me.
I have also found that previous "fixers" have left out parts that are key to a successful and happy motor.
TL.
