Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00)

Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00)

This water pump impeller service kit is designed for Yamaha 2-Stroke 4HP and 5HP outboards (1988–2019) and 4-Stroke F4, F5, and F6 1-cylinder models (1998–2011). It provides all the necessary components to service and restore your engine's cooling system.

This kit is a direct replacement for Yamaha OEM part numbers 6E0-W0078-A2-00, 6E0-W0078-00-00, 6E0-W0078-01-00, 6E0-W0078-02-00, and 6E0-W0078-A3-00.

• Installation Method: Direct replacement for the original water pump components.
• Core Components: Includes the impeller, housing insert cup, plate, gasket, and key.
• Durable Materials: Features a robust rubber impeller and corrosion-resistant housing components.

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 Yamaha owners, here’s a guide to help you identify your engine’s serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Impeller (6E0-44352-00)
• 1 x Water Pump Housing Insert Cup
• 1 x Impeller Plate
• 1 x Gasket
• 1 x Impeller Key
• Multiple x Mounting Hardware (bolts/screws)

Installation Guide

1. Safety First: Disconnect the spark plug leads and the battery cables to prevent accidental starting.
2. Access the Lower Unit: Shift the outboard into neutral and remove the bolts securing the lower unit (gearcase) to the engine's upper section.
3. Remove the Lower Unit: Carefully lower the gearcase away from the upper housing. The driveshaft will slide out.
4. Disassemble the Water Pump: Unscrew the bolts holding the water pump housing cover. Lift the cover off to expose the impeller.
5. Remove Old Components: Take note of the impeller's rotational direction. Remove the old impeller, impeller key, gaskets, and wear plate.
6. Clean and Inspect: Thoroughly clean all surfaces, removing any old gasket material or debris. Inspect the housing for cracks or warping.
7. Install New Parts: Place the new gasket and impeller plate onto the gearcase. Install the impeller key into the driveshaft.
8. Install New Impeller: Slide the new impeller down the driveshaft while turning the shaft clockwise to bed the vanes correctly inside the housing cup.
9. Reassemble the Pump: Place the housing cup over the impeller and reinstall the housing cover, tightening the bolts to the manufacturer's specified torque.
10. Reattach Lower Unit: Guide the driveshaft back into the engine and reinstall the lower unit. Tighten all mounting bolts securely.
11. Test Operation: Reconnect the spark plugs and battery. Start the engine in a test tank or with a water source attached to ensure a strong water stream from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my Yamaha engine?
A: First, check the "Compatible Engine Models" table to ensure your engine's model and year range are listed. This kit is specifically for Yamaha 2-Stroke 4HP/5HP (1988–2019) and 4-Stroke F4/F5/F6 (1998–2011) 1-cylinder models. Second, verify your current part number matches one of the numbers in the cross-reference list, such as 6E0-W0078-A2-00.

Q: What are the signs my water pump impeller is failing?
A: The most common signs are the engine overheating, an alarm sounding (if equipped), or a weak or non-existent water stream from the "tell-tale" cooling system outlet. Upon inspection, a failing impeller may be cracked, brittle, or have broken vanes.

Q: How often should I replace the water pump impeller?
A: For preventative maintenance, it is best practice to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation. Replacement frequency depends on usage and water conditions (e.g., saltwater and sandy/silty water cause more wear).

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.