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

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

This water pump impeller kit provides a reliable solution for maintaining the cooling system on specific Johnson and Evinrude outboard engines. It is designed for 4 HP (1986-1992), 5 HP (1980-1983, 1996-2001), 6 HP (1984-2005), and 8 HP (1980-2005) models.

This kit serves as a direct replacement for Johnson/Evinrude part number 396644 / 0396644, Sierra 18-4529, and GLM 12065.

• Complete Assembly: The kit includes the impeller, wear plate, housing cup, gaskets, and all necessary mounting hardware for a full replacement.
• Direct Fitment: Engineered to match OEM specifications for a straightforward, direct replacement installation.

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. Disconnect the battery and safely remove the lower unit (gearcase) from the outboard motor.
2. Locate the water pump housing on the lower unit and remove the bolts securing it.
3. Lift the housing off and carefully remove the old impeller, noting the rotational direction of its vanes.
4. Remove the old wear plate, gaskets, and seals that are included in the new kit.
5. Thoroughly clean all mating surfaces of the housing and base plate to ensure a proper seal.
6. Install the new gaskets, wear plate, and seals provided in the kit.
7. Insert the new drive key and slide the new impeller onto the driveshaft.
8. While pushing down, turn the driveshaft clockwise to correctly bend the impeller vanes and install the housing.
9. Secure the housing with bolts, tightening them to the manufacturer's specified torque.
10. Reinstall the lower unit, reconnect the battery, and test the engine in water to verify strong water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?
Check the 'Compatible Engine Models' table on this page. Match your engine's brand, model, horsepower, and year range. You can also compare your existing part number to those in the 'Part Number Cross-Reference' list to ensure compatibility.

What are the signs of a failing water pump impeller?
Common signs include the engine overheating at idle or low speeds, a weak or inconsistent water stream from the tell-tale (pee) outlet, or a complete lack of water circulation. A brittle or cracked impeller discovered during inspection also indicates a need for replacement.

How often should I replace the water pump impeller?
For most outboards, we recommend inspecting the impeller annually and replacing it every 1-2 years or 100-200 hours of use, whichever comes first. Service intervals should be shorter if the engine is used frequently in saltwater or in water with heavy sediment.

OEM vs. Aftermarket?
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.

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

What is your warranty and return policy?
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.