Replacement Spa Motors
How to Determine Your Spa Motor Size
The easiest way to determine whether your spa takes a 48-frame or 56-frame motor is to measure between the thru-bolts. These are the bolts that run the length of the motor and screw into the four legs of the wet-end volute or seal plate.
If you measure 3 5/8" between bolts = 48 frame motor
If you measure 4 1/8" between bolts = 56 frame motor
Other motors such as square flange Jacuzzi 56J motors (lower on this page) and round face C bracket motors (bottom of this page) are all 56 frame size.