Some of the recent engine cooling issues may now be resolved after listening to the complaints & observations (I do better on the phone than computer)
Two of the common ski boat pump impellers are very similar & and sort of work interchangeably but not really. A Johnson 812B impeller and a Jabsco 22120 look identical & will fit into each others housing, however the Johnson is 2" wide and the Jabsco is 1 29/32" wide (thats .093" shorter) The short impeller inside the Johnson pump will pump but not build proper pressure, the Johnson impeller inside the Jabsco pump will be tough to squeeze the cover on, but it will go, & if it doesn't overheat the impeller blades but wears in may work if it makes the first hour or so. To complicate matters aftermarket suppliers like Sierra add confusion to the issue with their numbers.
When in doubt..CALL
Engine suppliers have used several different pumps, and different versions changing from one to another mid-year, model year, or whenever they run out of one & go to another! When I compared my cost for a "real pump" to a popular online parts store they had a crank driven similar looking pump to what we used for only $160.00 (but it had a small 1" impeller, not the 2") so be carefull out there.
