Re: stuck impeller
Depends on the year of the motor.
If it has the older slotted driveshaft and impeller with a metal key, soak it in blaster or other penetrating oil. Then if it won't release, cut away the rubber behind the key slot, then cut into the back of the slot with a Dremel and wedge the cut to break the brass ring.
If it is the newer, teardrop nylon key, you can usually break them free by holding the driveshaft so that it cannot turn and then giving the impeller a sharp twist clockwise.
When you replace the impeller, grease on the driveshaft will help to prevent the binding in the future.
