Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP (Replaces 396644, 0396644, 18-4529)

Water Pump Impeller Kit – Fits Johnson/Evinrude 4-8 HP (Replaces 396644, 18-4529)

This water pump impeller kit is designed for Johnson/Evinrude 4-8 HP 2-Stroke outboards (1980-2005) and 5-6 HP 4-Stroke (128cc) outboards (1998-2004). It provides a direct-fit replacement solution for your original water pump components, ensuring reliable engine cooling.

This kit serves as a direct replacement for Johnson/Evinrude part numbers 396644 / 0396644, Sierra 18-4529, and GLM 12255.

• Engineered with marine-grade materials for durability in freshwater and saltwater environments.
• Includes all necessary gaskets, seals, and hardware for a complete rebuild of the impeller assembly.
• Designed for a direct fit into the original water pump housing, simplifying 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 Impeller (389576)
• 1 x Pin/Drive Key (300611)
• 1 x Pump Cup/Impeller Housing Cup (324641)
• 1 x Wear Plate (324640)
• 2 x Gaskets (325040)
• 1 x O-Ring (303191)
• 2 x Grommets (302497, 321129)
• 4 x Screws (324430)

Installation Guide

1. Safety First: Disconnect the battery and spark plug wires before beginning any work.
2. Access the Lower Unit: Drain the gearcase lubricant. Unbolt and remove the lower unit (gearcase) from the outboard's driveshaft housing.
3. Disassemble the Water Pump: Locate the water pump housing on top of the gearcase. Remove the bolts securing the housing to access the impeller.
4. Inspect and Remove Old Parts: Take note of the orientation of all parts. Remove the old impeller, gaskets, wear plate, and seals. Clean all mating surfaces thoroughly.
5. Install New Components: Lightly grease the new wear plate and pump cup. Install the new drive key and slide the new impeller onto the driveshaft, rotating it in the direction of engine operation.
6. Reassemble and Test: Install the new gaskets and re-secure the housing. Re-install the lower unit, refill the gearcase lubricant, and reconnect the battery/spark plugs. Test the engine using a water source (flushing muffs) to confirm a strong water stream from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this fits my engine?
A: The best way is to check the part number on your original component and compare it to the numbers in our "Part Number Cross-Reference" table. You should also verify your engine's make, model, and year against our "Compatible Engine Models" list.

Q: Does this kit include the entire water pump housing?
A: No, this is a water pump impeller kit and does not include the main plastic or metal housing. It is designed to rebuild the wearable components inside your existing housing.

Q: What are the signs of a failing impeller?
A: Common signs include the engine overheating at idle or low speeds, and a weak or non-existent water stream from the "tell-tale" outlet on your outboard.

Q: How often should I replace my water pump impeller?
A: As a general maintenance rule, it is recommended to inspect and likely replace your impeller every 1 to 2 years, or every 100-200 hours of use, to prevent engine damage from overheating. This interval can be shorter if you frequently operate in sandy or silty water.

Q: OEM vs. Aftermarket?
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.