Water Pump Impeller Kit - Fits Yamaha 4HP/5HP Outboard Motors (Replaces 6E0-W0078-A2-00)

Water Pump Impeller Kit - Fits Yamaha 4HP/5HP Outboard Motors (Replaces 6E0-W0078-A2-00)

This water pump impeller repair kit provides the necessary components to service the lower unit water pump on Yamaha 2-stroke 4HP (1984–1999) and 5HP (1984–2002) models, as well as 4-stroke F4 (1999–2008) outboards. It is designed to meet OEM specifications for a reliable, direct-fit replacement.

This kit is a direct replacement for Yamaha part numbers 6E0-W0078-A2-00, 6E0-W0078-02-00, 6E0-W0078-01-00, 6E0-W0078-00-00, 6E0-W0078-A3-00, and aftermarket parts AM6E0-W0078-A2, HJ YHJB-6E0.

• Engineered for a direct replacement installation.
• Includes all core components for a complete water pump service, including the impeller, housing, gaskets, and plates.
• Built with high-quality materials to ensure durability and reliable cooling performance.

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.

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Water Pump Housing (6E0-44311-00-00)
• 1 x Water Pump Gasket (6E0-44315-A0-00)
• 1 x Cartridge Insert (6E0-44322-02-00)
• 1 x Cartridge Outer Plate (6E0-44323-00-00)
• 1 x Impeller (6E0-44352-00-00)
• 1 x Water Seal Damper 2 (6E0-44366-00-00)
• 1 x Dowel Pin (93604-09066-00)
• 4 x Bolt (97080-06045-00/97095-06045-00)

Explosion Diagram

Installation Guide

1. Disconnect the battery and remove the engine cover.
2. Drain the lower unit gear lube.
3. Remove the bolts securing the lower unit and carefully separate it from the upper casing.
4. Unbolt and remove the old water pump housing.
5. Note the rotational direction of the old impeller vanes before removing it and its key.
6. Thoroughly clean the mounting surfaces, removing any old gasket material or sealant.
7. Install the new components in reverse order, starting with the new gasket, plate, impeller, and housing.
8. When installing the new impeller, turn the driveshaft clockwise to bend the vanes into the correct orientation inside the pump cup.
9. Secure the new water pump housing and torque the bolts to the manufacturer's recommended specification.
10. Re-attach the lower unit, ensuring the water tube and driveshaft align correctly.
11. Refill the gear lube with the recommended oil and reinstall the drain screws.
12. Connect a water supply to the lower unit and start the engine to confirm proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my Yamaha engine?
A: Check your engine's model, horsepower, and year against the "Compatible Engine Models" table. For Yamaha, we recommend using the serial number guide linked above to be certain. This kit is for specific 4HP and 5HP models produced between 1984 and 2008.

Q: My Mariner has a 6E0 serial number. Will this fit?
A: Yes, this kit is designed for Mariner 4A models with a "6E0" serial number and 5C models with a "6E3" serial number. Always verify compatibility using your specific model information, as year ranges can vary.

Q: How often should I replace my water pump impeller?
A: For optimal performance and engine safety, we recommend inspecting the impeller annually and replacing the entire water pump kit every 2-3 years or 200-300 hours of use, whichever comes first, especially if operating in saltwater or sandy conditions.

Q: What are the signs of a failing water pump?
A: Common symptoms include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, and a dry, cracked, or brittle impeller with a "set" vane direction upon inspection.

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.