Water Pump Impeller Repair Kit – Fits Yamaha 4-5HP Outboards (Replaces 6F5-W0078-00, 6F5-W0078-A0-00)

Water Pump Impeller Repair Kit – Fits Yamaha 4-5HP Outboards (Replaces 6F5-W0078-00, 6F5-W0078-A0-00)

This water pump repair kit is designed for Yamaha 4-5HP 2-Stroke (1984–2002) and F4 4HP 4-Stroke (1999–2008) outboard motors. It provides a complete solution for servicing your engine's cooling system to prevent overheating and ensure reliability.

It serves as a direct replacement for Yamaha part numbers 6F5-W0078-00-00, 6F5-W0078-A0-00, and 6E0-W0078-A2-00.

• Installation: Direct OEM-style replacement ensures a precise fit.
• Complete Kit: Includes all necessary gaskets, seals, impeller, and hardware for a full service.
• Impeller Material: Made from durable neoprene rubber for reliable 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.

Technical Specifications

Package Contents

• 1 x Water Seal Damper 2 (663-44366-00-00)
• 1 x Cartridge Insert (676-44322-00-00)
• 1 x Impeller (6F5-44352-00-00)
• 1 x Water Pump Gasket (676-44315-A1-00)
• 1 x Cartridge Outer Plate (676-44323-00-00)
• 1 x Cartridge Gasket (676-44324-A1-00)
• 1 x Water Pump Gasket (679-44316-A0-00)
• 2 x Bolts (97095-08055-00)
• 2 x Bolts (97095-08045-00)
• 4 x Washers (92990-08600-00)
• 1 x Woodruff Key (90280-04M00-00)

Installation Guide

1. Disconnect the negative battery cable and remove the engine cover.
2. Place a drain pan under the lower unit and remove the gear case drain and vent screws to drain the gear lube.
3. Remove the bolts securing the lower unit (gear case) to the outboard's leg.
4. Carefully lower and remove the lower unit from the engine.
5. Unbolt and remove the old water pump housing assembly from the lower unit.
6. Remove the old impeller, woodruff key, wear plate, and gaskets. Note their orientation before removal.
7. Thoroughly clean all mating surfaces, ensuring they are free of old gasket material, salt deposits, or corrosion.
8. Install the new gaskets, wear plate, and woodruff key. Slide the new impeller onto the driveshaft, rotating it clockwise to align the fins.
9. Install the new cartridge, seals, and housing. Ensure all components are seated correctly.
10. Tighten the housing bolts to the manufacturer's specified torque.
11. Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are correctly aligned.
12. Once secured, refill the gear case with fresh lubricant, and test the engine with a reliable water source to confirm proper water pump operation via the tell-tale stream.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my engine?
A: The surest way is to match your engine's model and year against our "Compatible Engine Models" table. For Yamaha models, you can use the linked serial number guide to verify your engine's details. If your specific model is not listed, this kit may not be correct.

Q: What are the common signs of a failing water pump impeller?
A: The most common symptom is a weak or non-existent water stream from the "tell-tale" outlet on the engine. Other signs include the engine overheating alarm sounding or the engine running hotter than usual. A damaged impeller can cause severe engine damage if not replaced.

Q: How often should I replace the water pump impeller?
A: For preventative maintenance and maximum reliability, it's best practice to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).

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.