I do not have the answer for you but could try to point you in the right direction. It is unlikely that you will find a direct replacement. Some of these motors were custom build for Recovery Engineering. Here is what you need to ascertain:
Voltage: 12V
Power: This is either a 1/3 hp or 1/4 hp motor. Either one will do.
RPMs: If your
watermaker was ticking 2x a second (roughly) then you need a 1750
rpm motor. If 4x a second, then 3450 rpms. Try to remember how often it ticked. This is most important.
Duty: You want continuous duty
Case and shaft diameter: measure your existing motor
Then, go to the websites of Baldor, Leeson, etc. and try to match as closely as possible. You can often get a much cheaper motor on ebay.
It also helps to call Katadyne a couple of times. Sometimes you get a much more helpful rep who is willing to volunteer the information. I had to call three times until I got the specs of the 40e motor.