Water Pump Impeller Kit – Fits Yamaha 4-Stroke 70HP F70A Outboard Engines (Replaces 6CJ-W0078-00, 6CJ-W0078-01)

Water Pump Impeller Kit – Fits Yamaha 4-Stroke 70HP F70A Outboard Engines (Replaces 6CJ-W0078-00, 6CJ-W0078-01)

This water pump impeller repair kit is designed for Yamaha 4-Stroke 40–70HP outboard motors, including models F40G, F70, and F70A from 2010 to current.

It serves as a direct replacement for Yamaha OEM part numbers 6CJ-W0078-00, 6CJ-W0078-01, and 6CJ-W0078-02, as well as Sierra part number 18-3494.

• Includes a high-quality neoprene rubber impeller, housing, gaskets, and all necessary hardware for a complete overhaul.
• Engineered for direct OEM replacement, ensuring proper fit and function.
• Materials include a durable neoprene impeller and stainless steel components for corrosion resistance.

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 Neoprene Impeller (6H3-44352-00-00)
• 1 x Cup, Insert (63D-44322-00-00)
• 1 x Plate, Wear (6CJ-44323-00-00)
• 1 x Water Pump Gasket (6CJ-44315-00-00)
• 1 x Water Pump Gasket (6CJ-44316-00-00)
• 1 x Cartridge Gasket (6CJ-44324-00-00)
• 1 x Water Pump Housing Cover (63D-44312-00-00)
• 1 x Grommet (663-44366-00-00)
• 1 x O-Ring (93210-46044)
• 1 x Woodruff Key (90280-03M03-00)
• 2 x Oil Seal (93101-23070-00)
• 2 x Dowel Pin (93604-10M03-00)
• 2 x Bolt with Washer (90119-08M33-00)
• 2 x Bolt with Washer (90119-08M14-00)

Installation Guide

1. Disconnect Power: Disconnect the negative battery cable before starting. Ensure the engine is shifted into neutral.
2. Remove Lower Unit: Remove the bolts securing the lower unit (gearcase) to the upper engine housing. Carefully lower and separate the unit.
3. Access Water Pump: Unbolt and remove the water pump housing cover, taking note of how the components are assembled.
4. Remove Old Impeller: Inspect the old impeller's vane direction before sliding it off the driveshaft. Remove the old gaskets and wear plate.
5. Clean and Prepare: Thoroughly clean all surfaces of the housing and replace the wear plate and gaskets provided in the kit.
6. Install New Impeller: Lightly lubricate the new impeller and slide it onto the driveshaft, twisting it clockwise to bend the vanes into the correct orientation.
7. Reassemble Pump: Reinstall the water pump housing, seals, and O-rings. Ensure all bolts are torqued to the manufacturer's specifications.
8. Reattach Lower Unit: Realign the lower unit, ensuring the driveshaft, water tube, and shift shaft are correctly seated. Bolt it securely back into place.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my Yamaha engine?
A: First, verify your engine's model, year, and horsepower are listed in the "Compatible Engine Models" table. For Yamaha owners, you can use the official Yamaha Serial Number Guide to find your details. This kit replaces OEM part numbers 6CJ-W0078-00, 6CJ-W0078-01, and 6CJ-W0078-02, so cross-referencing with your service manual is the best way to ensure a match.

Q: What are the signs of a failing water pump impeller?
A: The most common symptom is engine overheating, often triggered by an alarm. You may also notice a weak or nonexistent stream of water from the engine's "tell-tale" outlet. Unusual grinding or rattling noises from the lower unit can also indicate a worn or damaged impeller.

Q: How often should I replace the water pump impeller?
A: As a general rule 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. This interval may be shorter if you frequently operate in sandy or silty water.

Q: Is this an OEM part or an aftermarket one?
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.