Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-01-00, 6H3-W0078-02-00, 6H3-W0078-A0-00)

Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards

This water pump repair kit is designed for select Yamaha 2-stroke and 4-stroke high thrust outboard motors from 50 to 70 horsepower. It provides the necessary components to restore the cooling system, preventing overheating and ensuring engine longevity.

This kit is a direct replacement for OEM part numbers 6H3-W0078-01-00, 6H3-W0078-02-00, and 6H3-W0078-A0-00, as well as aftermarket parts from Sierra, UanofCn, and GHmarine.

• Compatible with Yamaha 2-Stroke (60-70 HP) and 4-Stroke High Thrust (50-60 HP) models.
• Kit includes a neoprene impeller, gaskets, wear plate, and hardware for a complete rebuild.
• Engineered as a direct-fit replacement for straightforward installation.

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.

Yamaha 2-Stroke Outboards

Yamaha 4-Stroke High Thrust Outboards

Technical Specifications

Package Contents

• 1 x Water Pump Impeller (6H3-44352-00-00/697-44352-00)
• 1 x Key, Woodruff (90280-03M03-00)
• 1 x Gasket, Water Pump (6H3-44315-A0-00)
• 1 x Gasket, Water Pump (688-44316-A0-00)
• 1 x Gasket, Outer Plate (6H3-44324-A0-00)
• 1 x Cup, Impeller (663-44322-00-00)
• 1 x Plate, Wear (6H3-44323-00-00)
• 1 x O-Ring (93210-46044-00)
• 2 x Bolt (97095-08045-00)
• 2 x Bolt (97395-08055-00)

Note: Some aftermarket kits (e.g., Sierra 18-3466) also include a Water Pump Housing (6H3-44311-00-00). Please verify contents before purchasing.

Installation Guide

1. Disconnect the battery and remove the engine cover.
2. Drain the gearcase lube from the lower unit.
3. Remove the propeller and any associated hardware.
4. Unbolt and carefully lower the gearcase assembly from the engine.
5. Locate and unbolt the water pump housing to expose the impeller.
6. Remove the old impeller, gaskets, wear plate, and cup. Note their orientation.
7. Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
8. Install the new wear plate, gaskets, and impeller cup.
9. Slide the new Woodruff key onto the driveshaft and install the new impeller, turning the fins clockwise as you slide the housing over it.
10. Secure the new housing with the provided bolts, tightening them to factory torque specifications.
11. Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are properly aligned.
12. Refill the gearcase with fresh lube, and test the engine's cooling system in water before resuming normal operation.

Troubleshooting & FAQ

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

A: Check your engine's model and year against the "Compatible Engine Models" table. For High Thrust models (like T50/T60), ensure your specific model (e.g., FT50, FT60) is listed. Cross-referencing your existing part number with our "Part Number Cross-Reference" table is the best way to ensure an exact match.

Q: What are the signs that my water pump needs to be replaced?

A: Common signs include the engine overheating at idle or low speeds, a weak or non-existent stream of water from the "telltale" outlet, and a brittle, cracked, or deformed impeller found during inspection.

Q: How often should I replace my water pump impeller?

A: For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use, depending on operating conditions (e.g., saltwater vs. freshwater).

Q: Does this kit include the plastic water pump housing?

A: This standard kit configuration does not include the water pump housing. The kit that includes the housing is equivalent to Sierra part number 18-3466. Please verify the contents before ordering to ensure you receive the correct components for your needs.

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.