Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-02-00)

Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-02-00)

This water pump repair kit is designed for select Yamaha 2-stroke and 4-stroke outboard motors. It provides a reliable solution for maintaining your engine’s cooling system, ensuring optimal performance and preventing overheating. The kit fits various 50 HP, 60 HP, and 70 HP models manufactured between 1996 and 2023.

This assembly is a direct replacement for Yamaha part number 6H3-W0078-02-00 and Sierra part number 18-3465.

• Installation Location: Mounts on the lower unit (gearcase) to restore cooling system function.
• Complete Kit: Includes a new impeller, housing, gaskets, and all necessary hardware for a full rebuild.
• Engine Compatibility: Fits specific Yamaha 2-stroke models (60HP, 70HP) and 4-stroke high-thrust models (T50, T60).

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. Safety First: Disconnect the engine's battery cables before beginning work.
2. Remove Lower Unit: Unbolt and carefully detach the lower unit (gearcase) from the upper engine housing.
3. Access the Pump: Locate and unbolt the water pump housing to expose the old impeller and wear plate.
4. Remove Old Components: Take out the old impeller, gaskets, plates, and the woodruff key. Note their orientation.
5. Clean Surfaces: Thoroughly clean all mating surfaces, removing any old gasket material or debris.
6. Install New Parts: Install the new woodruff key, gaskets, and wear plate as per the diagram.
7. Install Impeller: Lightly grease the new impeller and slide it onto the driveshaft, turning the shaft clockwise to bed the vanes correctly.
8. Reassemble Pump: Install the new cartridge insert and outer housing, torquing the bolts to the manufacturer's specifications.
9. Reinstall Lower Unit: Carefully guide the lower unit back into place, ensuring the driveshaft, shift shaft, and water tube align correctly.
10. Test Operation: Reconnect the battery. Start the engine in a suitable water source and confirm a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my specific engine?
A: The most reliable method is to check your engine's model and year against the "Compatible Engine Models" table above. You can also use the "Part Number Cross-Reference" to see if our part number matches the OEM number listed for your motor in a parts diagram.

Q: What are common signs that a water pump needs replacing?
A: Key signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet, or a brittle, cracked, or deformed impeller found during routine inspection.

Q: How often should I replace my water pump or impeller?
A: For preventative maintenance, it is highly recommended to replace the impeller every 1 to 2 years or every 100-200 hours of use, especially for boats operated in saltwater or sandy conditions.

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.