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If your boat has an Evinrude water pump kit, you might not know when or how often to change it. Some go so far as to say you should replace the complete water pump each year, because all of it wears down. Others say you only have to replace the impeller.
The right answer really depends on what kind of boating you do; if you do it in muddy, sandy or debris-infected water, you might want to change your whole water pump annually. The same goes if you boat in dangerous waters or in areas where you occasionally run aground.
If that's you and it's time to change the water pump in your 40-horsepower Evinrude Tracker, here's how to do it.
What You'll Need
Make sure you have the following on hand before you start the pump changing process:
- A new water pump kit
- Gasket sealing compound
- Wheel bearing grease
- Pump housing, about 3 inches
- Impeller, about 3 5/8 inches.
Steps to follow
- Remove the lower unit from the boat.
- Remove the mounting bolts on the water pump.
- Remove the O-ring from the drive shaft.
- Remove the water pump case.
- Check for sand, dirt and debris in the powerhead. This would cause the powerhead to overheat. If there's some in there, flush it out with water.
- Remove the impeller with a screwdriver.
- Note the position of the plastic key, then remove and replace it.
- Clean the water pump key area.
- Use emery cloth to clean up the shaft, if necessary.
- Remove the water pump tube screw.
- Remove existing gasket compound from the lower unit.
- Mix the new gasket sealing compound well.
- Clean the water pump surface area of the lower unit.
- Place gasket sealing compound on both sides of the gasket.
- Install the wear plate.
- Install the impeller key.
- Note the position of the key held by wheel bearing grease.
- Install the pump cup in the pump housing.
- Line up the pump cup tabs in the pump housing.
- Cover the impeller with wheel bearing grease.
- Note the key location on the impeller before installing the drive shaft.
- Install the greased impeller on the drive shaft.
- Note the location for the seal O-ring area.
- Place the gasket sealing compound in seal O-ring area.
- Install large O-ring type pump housing seal.
- Remove any gasket sealing compound from the pump cup.
- Place grease in impeller area of the pump cup.
- Place the pump cup in the housing assembly on the drive shaft.
- Slowly turn the drive shaft in a clockwise direction, while simultaneously pressing down on the pump housing.
- Note the size of the new impeller and housing.
- Repeat step 29 again if the O-ring seal comes out of the pump housing.
- Turn the drive shaft in a clockwise direction while pressing down. Turn it four or five rotations until the impeller is seated.
- Install all bolts with two or three turns by hand to line up the pump housing.
- Complete the bolt installation.
- Add gasket compound to the bottom of the tub guide.
- Install screws in the tub guide and base assembly.
- Install a grommet on the water pump base.
- Note the position of the grommet and tub guide for clearance.
- Clean the O-ring area on the drive shaft.
- Install the O-ring on the drive shaft.
Not everyone will tell you to grease both the impeller and the inside of the cup area, but this does make installation easier. And don't forget to press down on the pump housing as you're slowly turning the outboard drive shaft clockwise.
- Make sure the impeller drive pin does not become disengaged with the driveshaft or impeller while the housing is being installed, or the pump will not operate properly.
Brenna Swanston is a freelance writer, editor and journalist. She covers topics including environment, agriculture and travel. She previously reported for the Sun newspaper in Santa Maria, Calif., and holds a bachelor's in journalism from California Polytechnic State University. Swanston is an avid traveler and loves jazz, yoga and craft beer.