Water Pump Impeller – Fits Johnson/Evinrude 4-8 HP Outboards (Replaces 389576, 433914)

Water Pump Impeller – Fits Johnson/Evinrude 4-8 HP Outboards (Replaces 389576, 433914)

This water pump impeller is designed for a range of Johnson/Evinrude outboard motors, including 4HP, 4.5HP, 5HP, 6HP, and 8HP 2-Stroke models (1980-1997) as well as 5HP and 6HP 4-Stroke models (1998 and up). It serves as a reliable replacement to maintain your engine's cooling system performance.

Engineered as a direct replacement for multiple OEM and aftermarket parts, this component ensures broad compatibility. It cross-references with Johnson/Evinrude 389576, 433914, 436137, 777822, 778225; Sierra 18-3091; Mallory 9-45214; GLM Marine 89500; and CEF 500354/500358.

• Constructed from high-quality neoprene rubber with a durable brass center hub.
• Features 6 precision-molded blades for efficient water flow.
• Engineered as a direct replacement part, though professional installation is recommended.

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 Serial Number Guide.

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (Replaces 389576/433914/436137/777822/778225)

Installation Guide

1. Safety First: Disconnect the battery and remove the engine cover.
2. Access the Lower Unit: Unbolt and carefully lower the gearcase from the upper engine housing.
3. Open the Pump Housing: Remove the bolts securing the water pump cover to access the impeller.
4. Note Orientation: Observe the direction of the old impeller's blades before removal.
5. Remove Old Impeller: Slide the old impeller off the driveshaft, removing the drive key if present.
6. Clean and Inspect: Clean any debris from the housing and inspect it for scoring, cracks, or wear.
7. Prepare New Impeller: Lightly lubricate the new impeller and the inside of the pump housing with marine grease.
8. Install New Impeller: Slide the new impeller onto the driveshaft. Rotate the shaft in its normal direction of operation (usually clockwise) to bend the blades correctly into the housing.
9. Reassemble: Re-install the water pump cover and a new gasket, tightening bolts to the manufacturer's specified torque.
10. Re-attach Lower Unit: Secure the lower unit back onto the engine.
11. Test Operation: Reconnect the battery and start the engine in water, confirming a steady stream from the cooling system's tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my engine?
A: Carefully check the "Compatible Engine Models" table, matching your engine's brand, model, horsepower, and year range. For Johnson/Evinrude engines, using the provided serial number guide is a reliable way to verify your exact model and year if you are unsure.

Q: What are the signs of a failing water pump impeller?
A: The most common signs are the engine overheating, a weak or nonexistent water stream from the "tell-tale" outlet, or an alarm from your engine's warning system. In severe cases, you may find a melted water pump housing upon inspection.

Q: How often should I replace the water pump impeller?
A: As a preventative maintenance measure, we recommend replacing the impeller every 1-2 years. If you frequently operate your boat in sandy, silty, or saltwater conditions, an annual replacement is advised to ensure reliability.

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.