Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke Outboard Motors (Replaces 6AH-W0078-00-00)

Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke Outboard Motors

This water pump impeller service kit provides everything needed for a complete replacement on select Yamaha 15 HP and 20 HP 4-stroke outboard motors. It is designed to restore the performance and reliability of your engine's cooling system.

This kit is a direct replacement for Yamaha part numbers 6AH-W0078-00-00, 6AH-W0078-01-00, 6AH-W0078-02-00, and Sierra Marine 18-3479. It is also equivalent to Yamaha part 68T-W0078-00-00.

• Engineered for direct OEM replacement for a perfect fit and hassle-free installation.
• Includes a new housing, impeller, wear plates, gaskets, and all necessary hardware for a full service.
• Manufactured in an ISO9002 certified factory to meet or exceed original equipment specifications.

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 (6AH-44311-00-00)
• 1 x Insert, Cartridge (63V-44322-00-00)
• 1 x Damper, Water Seal (6L2-44367-00-00)
• 1 x Water Pump Impeller (63V-44352-01-00)
• 1 x Impeller Key, Woodruff (664-44338-00-00)
• 1 x O-Ring (93210-49046-00)
• 1 x Outer Plate, Cartridge (6AH-44323-00-00/68T-44323-00-00)
• 2 x Plate (63V-44328-01-00)
• 2 x Pin, Dowel (93604-10M03-00/93604-12M07-00)
• 4 x Bolt (97095-08045-00)

Explosion Diagram

Installation Guide

1. Disconnect the negative battery cable and remove the engine cover. Disconnect the shift linkage.
2. Place a drain pan under the lower unit and remove the lower unit mounting bolts.
3. Carefully lower and remove the lower unit from the outboard motor.
4. Unscrew the bolts securing the water pump housing and lift the housing off.
5. Note the rotational direction of the old impeller fins before removing it.
6. Remove the old impeller, Woodruff key, wear plates, gaskets, and seals.
7. Thoroughly clean the mating surfaces of the housing and lower unit.
8. Install the new wear plates, gaskets, O-rings, and Woodruff key from the kit.
9. Slide the new impeller onto the driveshaft, turning the shaft clockwise to bed the fins correctly inside the housing.
10. Secure the new water pump housing with the new bolts, tightening them to the manufacturer's specified torque.
11. Re-install the lower unit, ensuring the driveshaft, water tube, and shift shaft are correctly aligned.
12. Reconnect the shift linkage and battery, start the engine, and confirm a steady water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my Yamaha engine?

First, check your engine's model and year against the "Compatible Engine Models" table above. This kit is specifically designed for Yamaha 15 HP (F15C, F15) and 20 HP (F20, F20A) 4-stroke models from 2006 onwards. Crucially, it does not fit F15B or F20B models. Always verify by cross-referencing your existing part numbers.

What are the signs of a failing water pump impeller?

The most common signs of a worn or damaged impeller are a weak or non-existent water stream from the engine's "tell-tale" outlet, frequent engine overheating alarms, steam from the exhaust, and a reduction in overall engine performance.

How often should the water pump impeller be replaced?

For preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of operation. If you frequently operate in sandy, silty, or saltwater environments, more frequent replacement is advised.

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.