Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP Outboards (Replaces 396644, 389844)

Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP Outboards (Replaces 396644, 389844)

This water pump impeller kit is designed for Johnson/Evinrude 4-8 HP, 2-stroke outboard engines manufactured between 1980 and 2005. It serves as a direct replacement for OEM components, restoring your engine's cooling system performance.

This kit provides direct replacements for Johnson/Evinrude part numbers 396644 / 0396644 and 389844, as well as Sierra 18-4529 and QuickMarine 0396644.

• Installation Method: Direct replacement for original factory components without modification.
• Compatibility: Designed for use with gasoline-powered 2-stroke marine outboard engines.
• Complete Assembly: Includes the impeller, wear plate, housing, gaskets, and essential mounting hardware for a full service.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson/Evinrude Serial Number Guide.

Technical Specifications

Package Contents

• 1 x Drive Key (331130/18-3026)
• 1 x Grommet (321129/18-1827)
• 1 x Grommet (302497/18-3329)
• 1 x Screws (324430/18-4277)
• 1 x Impeller Housing Plate (324640/18-4578)
• 1 x Impeller Housing Cup (324641/18-4551)
• 1 x Impeller Housing Gasket (325040/18-99156)
• 1 x Impeller Assembly (389576/18-3091)
• 1 x O-Ring (303191/18-7413)

Installation Guide

1. Safety First: Before starting, disconnect the spark plug wires and the battery to prevent accidental starting.
2. Access the Lower Unit: Shift the outboard into forward gear. Remove the bolts securing the lower unit (gearcase) to the upper leg assembly.
3. Remove the Lower Unit: Carefully lower the gearcase away from the engine. The driveshaft will slide out.
4. Disassemble the Water Pump: Unscrew the bolts on the top of the water pump housing and lift it off to expose the impeller and wear plate.
5. Inspect and Clean: Take note of the old parts' orientation before removing them. Clean any old gasket material or debris from the housing surfaces.
6. Install New Components: Lightly grease the new impeller and install it into the housing cup, turning the driveshaft clockwise to bend the vanes correctly. Place the new gaskets and wear plate.
7. Reassemble the Pump: Secure the housing with the new screws. Install the new drive key.
8. Reinstall the Lower Unit: Guide the driveshaft back into the splines of the crankshaft, ensuring the water tube aligns correctly. Bolt the lower unit back into place.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific engine model?

A: This kit fits a wide range of Johnson/Evinrude 4, 5, 6, and 8 HP 2-stroke outboards from 1980 to 2005. Check the "Compatible Engine Models" table to verify your HP and year range. Cross-reference the OEM part number stamped on your old water pump housing or impeller with the numbers listed in our cross-reference table.

Q: I saw a review mentioning the key size was wrong. Is this a common issue?

A: While the kit is designed for broad compatibility, slight variations can exist across decades of engine production. We recommend comparing the new drive key and other components to your original parts before installation. If a part does not match, please contact us before proceeding.

Q: What are the signs that my water pump impeller is failing and needs replacement?

A: A weak or inconsistent water stream from the "telltale" outlet is the most common sign. Other indicators include the engine overheating alarm sounding or the engine running hotter than usual. It is recommended to replace the impeller every 1-3 years depending on use (e.g., saltwater vs. freshwater, hours of operation).

Q: This is an aftermarket part. How does it compare to the OEM version?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.