- 1). Remove the four bolts securing the water pump housing to the lower unit with a 1/2-inch socket. Slide or work the cover up off the driveshaft. If the impeller did not come off with the cover, work the impeller off the driveshaft.
- 2). Pull the impeller drive pin and the impeller O-ring away from the driveshaft. Remove the impeller plate. Clean the plate and lower unit of any remaining gasket material and/or sealant with acetone and a clean cloth.
- 3). Disassemble the water pump housing by removing the impeller, the insert, grommets and O-rings. Regardless of condition, replace the impeller, as well as the insert and the O-rings to ensure proper operation.
- 4). Apply a drop of waterproof gasket sealant to the four-ribbed driveshaft O-ring seal groove on the underside of the water pump housing, above the insert. Install the driveshaft O-ring into the groove in the underside of the water pump housing, above the insert.
- 5). Coat the outer diameter of the impeller insert using gasket sealant. Install the insert into the water pump housing. Use the square index tab to lock the insert into place in the housing. When installing the impeller to the water pump insert, be sure the drive pin slot is facing outward.
- 6). Apply a light coat of gear oil onto the insert and rotate the impeller counterclockwise as you push the impeller into the insert, to "set" the vanes in the direction in which they will rotate. Apply gasket sealant in the groove on the bottom rim of the housing that holds the housing-to-impeller plate O-ring. When you've finished putting the sealant in place, push the O-ring into the groove.
- 7). Install the water tube grommet into the impeller housing with the inside chamfered edge facing upward. Install and secure the water tube bracket to the housing using the retaining screw. Apply a bit of gasket sealant, this time in the groove for the pump housing grommet. Position the grommet in the top of the housing.
- 8). Apply a thin coat of gasket sealant to both sides of a new impeller plate gasket. Position the gasket and plate on the lower unit. Install the impeller O-ring over the driveshaft and slide it down into contact with the plate.
- 9). Apply a drop of needle bearing assembly grease onto the pump impeller drive pin. Place the pin against the flat on the driveshaft with the sharp edge facing the normal direction of rotation for the driveshaft, normally clockwise.
- 10
Slide the water pump assembly down the driveshaft, aligning the impeller housing with the index pins on the lower unit. Apply a thin coat of machine oil to the driveshaft if the water pump assembly seems to stick, or feels too tight. - 11
Before the impeller comes to the drive pin, rotate the driveshaft -- clockwise, as seen from above the motor, this time -- to align the drive pin with the slot in the impeller, then slide the pump the rest of the way down against the impeller plate. Make sure that the drive pin properly engages the impeller. - 12
Apply thread locker to the threads of the water pump housing bolts. Thread the four water pump housing bolts into the pump and lower unit until they are finger-tight. When they are as tight as you can get them with your hands, use a torque driver to tighten them to 65 inch-pounds.
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