Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP Outboards (Replaces 6H3-W0078-02-00)

Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP Outboards (Replaces 6H3-W0078-02-00)

This water pump repair kit is designed for Yamaha 2-Stroke 40-50 HP (1995-2009) and 4-Stroke 40-60 HP (1995-2009) outboard motors. It provides a reliable solution for maintaining your engine's cooling system for optimal performance and longevity.

This kit is a direct replacement for Yamaha part numbers 6H3-W0078-02-00, 6H3-W0078-01-00, 63D-W0078-01, and Sierra part numbers 18-3434 and 18-3415.

• Includes a complete set of gaskets, plates, and a high-performance impeller for a full service.
• Engineered as a direct-fit replacement for the original components.
• Restores cooling system efficiency to prevent engine overheating.

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 Cartridge Insert (663-44322-00-00)
• 1 x Impeller (6H3-44352-00-00)
• 1 x Water Pump Gasket 1 (6H3-44315-A0-00)
• 1 x Cartridge Outer Plate (6H3-44323-00-00)
• 1 x Cartridge Gasket (6H3-44324-A0-00)
• 1 x Water Pump Gasket 2 (688-44316-A0-00)
• 1 x O-Ring (93210-46044-00)
• 2 x Bolts, With Washer (90119-08M14-00)
• 2 x Bolts, With Washer (90119-08M33-00)
• 1 x Woodruff Key (90280-03M03-00)

Installation Guide

1. Disconnect the battery and ensure the engine is securely turned off.
2. Remove the lower unit (gearcase) from the outboard motor by unbolting it from the engine leg.
3. Unbolt and carefully lift the old water pump housing off the driveshaft.
4. Remove the old impeller, Woodruff key, wear plate, and gaskets. Take note of their orientation.
5. Thoroughly clean all mating surfaces, ensuring no old gasket material or debris remains.
6. Install the new gaskets, wear plate, and cartridge insert from the kit.
7. Slide the new Woodruff key into the slot on the driveshaft.
8. Install the new impeller, turning the driveshaft clockwise to help seat the vanes correctly inside the housing.
9. Place the new outer plate and gasket over the impeller.
10. Secure the pump housing with the new bolts provided, tightening them to the manufacturer's specified torque.
11. Reinstall the lower unit onto the outboard, ensuring the driveshaft and water tube align correctly.
12. Reconnect the battery and test the engine using a water supply (flushing muffs) to confirm proper water flow from the telltale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific Yamaha engine model?

A: Check your engine's model, horsepower, and year against our compatibility table. For precise verification, consult the Yamaha Serial Number Guide linked above or cross-reference your existing part number with our list. This ensures you order the correct component for a successful repair.

Q: What are the signs of a failing water pump impeller?

A: The most common signs include the engine overheating, a weak or non-existent water stream from the "telltale" indicator, or a burnt rubber smell. Upon inspection, a failing impeller may appear brittle, cracked, or have missing vanes.

Q: How often should the water pump impeller be replaced?

A: As a crucial part of preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years or 100-200 hours of use. Frequent operation in saltwater or sandy/silty conditions may require more frequent replacement.

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.