Hello James,
I'm not sure I have the answer to your question, but I suspect the pumps can be rebuilt to last longer than the motors they serve. Here's a closeup of the cam, and I see some scoring marks indicating many years of service. Brass is not necessarily a hard metal, but in this application it lasts a long time.
The neoprene or nitrile impellers don't seem to mind a little scoring. That scoring could have happened momentarily if the boat was scuffed onto a sand bar, or if the propellers were reversing and kicking up a lot of sand into the intakes. Once the silica gets on the brass, it would erode it like sandpaper. Personally I don't have any problem putting a pump with a little scoring like this back in service. I suppose you could polish it out with some fine grit sandpaper.
Not sure if you can still get replacement cams for these pumps, if so, they would have an almost indefinite life span.
Made In USA, quality to match the motors and the Chris Craft quality of the era too!
Paul
