Essential Maintenance: Replacing Outboard Impellers

When it comes to essential outboard maintenance, one simple little piece of plastic makes a world of difference: the water pump impeller.

Outboard water pump impeller replacement

Replacing the impeller ensures the motor cools properly, protecting the engine from overheating and severe damage. The impeller is a small rotating component with plastic blades. As it rotates within the water pump housing, the blades push cold water into and through the outboard’s cooling system. 

Damaged outboard water pump impeller

The plastic blades of an impeller have a limited lifespan and are prone to cracking or breaking over time. When this happens, the impeller no longer sends enough (or any) cold water through the cooling system, causing the motor to overheat. When an outboard overheats, the best-case scenario is the motor will stop running, while the worst-case scenario is the heat gets so extreme that a piston in the engine seizes. 

If you replace the impeller at least after every 200 hours of use, you’ll never have to worry about it failing or the damage that comes with it. Many outboard owners prefer to replace their impellers once a year regardless of the number of hours put on the motor. It’s a cheap, easy fix, so why not?

Replacing an Impeller: What Else?

As we already covered, replacing the water pump impeller is an essential part of basic outboard maintenance, and doesn’t take much time or money to get done. 

Johnson outboard water pump impeller

Johnson outboard motor impeller

Johnson impeller

While fitting a new impeller, take advantage the opportunity to inspect the driveshaft and shift shaft oil seals and replace them too if necessary. Whenever you’re ready to buy a new impeller for your outboard’s water pump, keep in mind! We have a large selection of water pump impellers at great prices.

If you need help finding one for your outboard, check out the video above for reference on how to find a water pump impeller in a parts diagram, or contact us for assistance. 



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