We had the Jabsco 31755 pump and the check valve failed this past week causing it to cycle.  I purchased the Jabsco replacement for the 31755 from West Marine, the Jabsco Parmax HD-4.  It was a HUGE mistake, the pump is so loud that you can hear it outside of the boat.  I am removing it this week and I'm going to order a different pump, probably one of the ones recommended here.

I know this isn't a recommendation, but I figured I would let you know NOT to buy this pump.

Ben
Jazzy, 306