Why the Impeller Matters
Your boat's water pump impeller is the small rubber component responsible for circulating cooling water through your outboard or sterndrive engine. When it fails, your engine can overheat within minutes — causing serious and expensive damage.
Signs Your Impeller Needs Replacing
- Engine temperature gauge running high
- Weak or no water stream from the tell-tale (pee hole)
- Engine overheating alarm triggering
- It's been more than 2 years or 100 hours since the last replacement
What You'll Need
- Replacement impeller kit (make sure it matches your engine make/model/year)
- Basic hand tools (screwdrivers, pliers, socket set)
- Marine grease or petroleum jelly
- Gasket scraper
Step-by-Step Replacement
- Flush and flush again — Run fresh water through the engine before starting work.
- Remove the lower unit — Disconnect the shift rod and drain the gear lube before dropping the lower unit.
- Access the water pump housing — Remove the bolts securing the pump housing to the lower unit.
- Pull the old impeller — Use pliers if needed. Inspect the wear plate and housing for scoring or damage.
- Install the new impeller — Apply marine grease and insert rotating in the correct direction.
- Reassemble — Replace the housing, gasket, and wear plate. Refill gear lube.
- Test run — Start the engine in a test tank or on the water and verify a strong tell-tale stream.
Shop Impellers at Nick Marine
We stock impellers for Yamaha, Mercury, Johnson/Evinrude, Honda, Sea-Doo, and more. If you're not sure which one fits your engine, call us at 623-252-3566 and Nick will track it down for you.
Nick Marine — Glendale, AZ — We Know Boat Parts