Water Pump Repair Kit – Fits Yamaha 40HP 2-Stroke (Replaces 679-W0078-A1-00, 6F5-W0078-A0-00)
Water Pump Repair Kit – Fits Yamaha 40HP 2-Stroke (Replaces 679-W0078-A1-00, 6F5-W0078-A0-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Pump Repair Kit – Fits Yamaha 40HP 2-Stroke (Replaces 679-W00...
Water Pump Repair Kit – Fits Yamaha 40HP 2-Stroke (Replaces 679-W0078-A1-00, 6F5-W0078-A0-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit – Fits Yamaha 40HP 2-Stroke (Replaces 679-W0078-A1-00, 6F5-W0078-A0-00) provides all essential components to service and restore your outboard's cooling system. It is designed for Yamaha 2-Stroke 40HP models including C40 and CV40 (1990–1997) and select Mariner 40HP 2-Stroke models.
This kit serves as a direct interchange for Yamaha part numbers 679-W0078-A1-00, 6F5-W0078-A0-00, Sierra 18-3397, and Mallory 9-48604, among others.
- Engineered as a direct OEM-spec replacement for a precise fit.
- Includes all necessary gaskets, seals, impeller, and hardware for a complete water pump overhaul.
- Note: The water pump housing is not included with this kit and must be purchased separately if needed.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 679-W0078-A1-00 |
| Yamaha | 679-W0078-A0-00 |
| Yamaha | 679-W0078-00-00 |
| Yamaha | 679-W0078-01-00 |
| Yamaha | 6F5-W0078-A0-00 |
| Sierra | 18-3397 |
| Sierra | 18-3398 |
| Mallory | 9-48604 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha models, this kit fits various C40 and CV40 outboards from 1990 to 1997. Please verify your specific model and year.
This kit is compatible with select 40HP 2-stroke Mariner outboards that use OEM part numbers 84363M, 84363T, or 99971M. Verify your engine's requirements before purchase.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | CV40ELD | 40 | 2-Stroke | 1990 | 6F5-W0078-A0-00 | |
| Yamaha | CV40EL | 40 | 2-Stroke | 1990 | 6F5-W0078-A0-00 | |
| Yamaha | C40ELR | 40 | 2-Stroke | 1991–1997 | 679-W0078-A1-00 | |
| Yamaha | C40ESH | 40 | 2-Stroke | 1997 | 679-W0078-A1-00 | |
| Yamaha | C40MLH | 40 | 2-Stroke | 1994–1995 | 679-W0078-A1-00 | |
| Yamaha | C40MSH | 40 | 2-Stroke | 1992–1997 | 679-W0078-A1-00 | |
| Yamaha | C40PLR | 40 | 2-Stroke | 1992–1997 | 679-W0078-A1-00 | |
| Mariner | 40HP (selected models) | 40 | 2-Stroke | 84363M, 84363T, 99971M |
Technical Specs
- Product Type
- Water Pump Repair Kit
- Installation
- Direct OEM replacement
- Housing
- Not included (housing sold separately)
- Kit Contents
- Includes all necessary gaskets, seals, impeller, and hardware for water pump service
What’s in the Box
- 1 × Water Seal (663-44366-00-00)
- 1 × Water Pump Gasket (676-44315-A0-00/676-44315-A1-00)
- 1 × Insert Cup (676-44322-00-00)
- 1 × Outer Plate, Cartridge (676-44323-00-00)
- 1 × Cartridge Gasket (676-44324-A0-00/676-44324-A1-00)
- 1 × Water Pump Gasket (679-44316-A0-00/679-44316-A1-00)
- 1 × Impeller (6F5-44352-00-00)
- 1 × Woodruff Key (90280-04M00-00)
- 4 × Washer, Plain (92990-08600-00)
- 2 × Bolt, Hexagon (97095-08045-00)
- 2 × Bolt, Hexagon (97095-08055-00)
Installation Notes
- Disconnect the negative battery cable for safety.
- Unbolt and remove the lower unit (gearcase) from the outboard's midsection. Keep track of all hardware.
- Place the lower unit on a suitable workbench. Remove the bolts securing the water pump housing.
- Lift the housing and remove the old impeller, gaskets, wear plate, and seals. Note the orientation of the impeller vanes.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new components from the kit in the reverse order of disassembly. Lightly grease the new seals and gaskets.
- When installing the new impeller, turn the driveshaft in its normal direction of rotation to correctly seat the vanes inside the cup.
- Reassemble the pump housing and torque its bolts to the manufacturer's specifications.
- Reinstall the lower unit onto the midsection, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Once assembled, test the engine using a water supply (flushing muffs or in water) to confirm that water is pumping correctly from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my specific engine?
This kit is designed for Yamaha 40HP 2-Stroke C40 and CV40 models from 1990–1997 and select 40HP Mariner outboards. The most reliable way to confirm fitment is to match your engine's model and serial number against our compatibility table and cross-reference the OEM part number.
Does this kit include the water pump housing?
No, this kit contains the internal service components (impeller, gaskets, seals, plates, hardware) but does not include the upper or lower water pump housing. Housings are sold separately.
What are the common signs of a failing water pump?
A weak or non-existent water stream from the "tell-tale" outlet is the most common sign. Other indicators include engine overheating alarms, steam from the exhaust, or a prematurely worn or melted impeller discovered during inspection.
How often should I replace my water pump impeller?
As a key part of preventative maintenance, we recommend servicing the water pump every 100 hours of use or annually, whichever comes first. This interval should be shortened if the engine is operated in sandy, silty, or saltwater environments.
The part number on my old part is 6F5-W0078-A0-00. Will this kit work?
Yes, this kit is a direct aftermarket replacement for Yamaha OEM part number 6F5-W0078-A0-00, along with several other superseded numbers like 679-W0078-A1-00. Please see our Part Number Matrix for a full list of cross-references.
Is any special grease needed for installation?
While not included, applying a thin layer of marine-grade, water-insoluble grease to the impeller, seals, and inside the pump cup can ease installation and improve initial priming. Do not use petroleum-based grease on rubber components.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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