I did it ....
... this past winter. Do you have a "B" engine (check the serial number). If so there is no gasket on the pump. Remove the four nuts on the studs holding the lower unit on the housing. Pull straight off because the drive shaft is coming out with the lower unit. The water pump sits on top of the lower unit with the drive daft going through it. Clean the saft well. Remove the top cover on the pump taking care not to damage the seal. From here on out it is a simple task to remove and replace the impeller and its rub plate. (Note the direction of deflection of the vanes. I drew a picture)My pump did not have gaskets so I assembled it using a very fine film of marine silicone sealant on the pumps mating surfaces. (This is a good time to change the lower unit's oil, too.) Check the rubber gasket on the pump's water pipe(It's in the housing, on a fixed metal pipe) It must mate to the pump's outlet on reassembly. Assemble everything in reverse order, carefully seating the drive shaft. Mine slipped right into place easily. I hope this helps, Wright Ellis Whisky II
