Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00-00)

Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00-00)

This water pump repair kit is engineered for Yamaha F40 and F70 4-stroke outboard motors. It provides all necessary components to rebuild the water pump assembly for a complete and reliable service.

This kit is a direct replacement for Yamaha part numbers 6CJ-W0078-00-00 and 6CJ-W0078-01-00, as well as Sierra 18-3494 and Quicksilver 8M6012800.

• Includes all required gaskets, seals, plates, and hardware for a full replacement.
• Designed for direct OEM-replacement fitment, ensuring a straightforward installation.
• Engineered with stainless steel components and a durable rubber impeller to restore cooling 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 Insert, Cartridge (63D-44322-00-00)
• 1 x Gasket, Water Pump (6CJ-44315-00-00)
• 1 x Cover, Pump Housing (63D-44312-00-00)
• 1 x Damper, Water Seal 2 (663-44366-00-00)
• 1 x Impeller (6H3-44352-00-00)
• 1 x Key, Woodruff (90280-03M03-00)
• 2 x Oil Seal (93101-23070-00)
• 1 x O-Ring (93210-46044-00)
• 1 x Gasket, Water Pump (6CJ-44316-00-00)
• 1 x Outer Plate, Cartridge (6CJ-44323-00-00)
• 1 x Gasket, Cartridge (6CJ-44324-00-00)
• 2 x Pin, Dowel (93604-10M03-00)
• 2 x Bolt, With Washer (90119-08M33-00)
• 2 x Bolt, With Washer (90119-08M14-00)

Installation Guide

1. Disconnect the negative battery cable and remove the lower unit from the outboard motor.
2. Locate and unbolt the water pump housing, typically secured with four bolts.
3. Carefully lift the housing off and remove the old impeller, wear plate, and any gaskets.
4. Thoroughly clean all debris and old gasket material from the mounting surfaces.
5. Install the new cartridge insert and gaskets onto the lower unit.
6. Slide the new Woodruff key onto the driveshaft and install the new impeller, rotating the driveshaft clockwise to set the vanes.
7. Apply a light coat of marine grease to the inside of the new pump housing cover.
8. Install the new housing cover, aligning it correctly, and secure it with the provided bolts.
9. Reinstall the lower unit, reconnect the battery, and test the engine in water to confirm a strong water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my F40 or F70 engine?
Verify your engine's model and year against the compatible models table. You can also cross-reference your existing part number with the numbers in our list. For Yamaha owners, the serial number guide linked above can help you identify your exact engine details.

What are the signs my water pump impeller needs to be replaced?
Common signs of a failing impeller include the engine overheating at idle or low speeds, a weak or intermittent "tell-tale" water stream, or a visual inspection revealing brittle, cracked, or deformed impeller vanes.

How often should I replace my water pump impeller?
For optimal engine protection and cooling, we recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of operation, especially if you frequently operate in saltwater or abrasive conditions.

OEM vs. Aftermarket?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.