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

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

This water pump impeller repair kit provides a complete solution for servicing the cooling system on Yamaha 70 HP F70A 4-stroke outboard motors (2010–2021). It is designed for models with serial numbers starting with 6D7, ensuring a precise fit and restoring cooling performance.

Engineered to meet or exceed OEM specifications, this kit serves as a direct replacement for Yamaha parts 6CJ-W0078-00-00 and 6CJ-W0078-01-00, as well as aftermarket equivalents like Sierra 18-3494.

• Complete Service Kit: Includes the impeller, housing, wear plate, gaskets, seals, and all necessary hardware for a full replacement.
• Direct Replacement: Designed for a direct fit, requiring access to the outboard's lower unit for installation.
• Engine Compatibility: Specifically for Yamaha 70 HP 4-stroke models F70LA and F70A.

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 Cover, Water Pump Housing (63D-44312-00/18-9083)
• 1 x Cup, Insert (63D-44322-00/18-3449)
• 2 x Seal, Water Damper (663-44366-00/18-1830)
• 1 x Gasket, Water Pump (6CJ-44315-00/18-0448)
• 1 x Gasket, Water Pump (6CJ-44316-00/18-0449)
• 1 x Gasket, Water Pump (6CJ-44324-00/18-0450)
• 1 x Plate, Wear (6CJ-44323-00/18-3186)
• 1 x Impeller (6H3-44352-00/18-3069)
• 2 x Bolt, With Washer (90119-08M14)
• 2 x Bolt, With Washer (90119-08M33/18-0260)
• 1 x Key, Woodruff (90280-03M03/18-3297)
• 2 x Oil Seal (93101-23070/18-0297)
• 1 x O-Ring (93210-46044/18-7436)
• 2 x Pin, Dowel (93604-10M03/18-43717)

Installation Guide

1. Disconnect Power: Disconnect the battery and shift the outboard into neutral.
2. Access Lower Unit: Remove the bolts securing the lower unit (gearcase) and carefully lower it from the engine.
3. Remove Old Pump: Unbolt and remove the old water pump housing to access the impeller.
4. Inspect and Clean: Clean all gasket surfaces and inspect the housing and wear plate for scoring or damage.
5. Install New Components: Lightly grease and install the new impeller, making sure the vanes are oriented correctly.
6. Assemble New Pump: Install the new gaskets, wear plate, cup, and housing per the diagram. Ensure the Woodruff key is properly seated.
7. Reinstall Lower Unit: Carefully guide the lower unit back into place, aligning the driveshaft, shift shaft, and water tube.
8. Secure and Test: Tighten the lower unit bolts to the manufacturer's torque specifications. Reconnect the battery and test the engine in water to verify a strong water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this fits my engine?
First, check the Compatible Engine Models table on this page. It is crucial to match your engine's model, horsepower, and year range. For Yamaha engines, you should also verify your serial number against the notes provided in the table to ensure an exact match.

What are the signs my water pump impeller needs replacing?
Common signs of a failing impeller include the engine overheating at idle or low speeds, and a weak or inconsistent stream of water from the tell-tale (peephole) outlet. Visual inspection during routine maintenance may also reveal cracked, brittle, or worn impeller vanes.

How often should I replace the water pump impeller?
For preventative maintenance, it is recommended to inspect and likely replace the water pump impeller every 100-200 hours of operation or at least once every one to two years, even if no issues are apparent. Usage in saltwater or sandy/murky water may require more frequent service.

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.