Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP (Replaces 6H3-W0078-02-00)
Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP (Replaces 6H3-W0078-02-00) is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP (Replaces 6H3...
Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP (Replaces 6H3-W0078-02-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Repair Kit – Fits Yamaha 40-60 HP Outboards provides all the necessary components to service your engine's cooling system. It is designed for Yamaha 2-stroke 40-50 HP (1995–2009) and 4-stroke 40-60 HP (1995–2009) outboard motors, ensuring a precise fit and reliable performance.
The kit serves as a direct interchange for Yamaha OEM part numbers 6H3-W0078-02-00, 6H3-W0078-01-00, 63D-W0078-01, and Sierra equivalents 18-3434 and 18-3415.
- Engineered for direct replacement and hassle-free installation.
- Includes a complete set of gaskets, seals, and hardware for a full water pump service.
- Restores cooling system performance to prevent engine overheating.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6H3-W0078-02-00 |
| Yamaha | 6H3-W0078-01-00 |
| Yamaha | 63D-W0078-01 |
| Sierra | 18-3434 |
| Sierra | 18-3415 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit fits a range of Yamaha 2-stroke and 4-stroke outboard motors as detailed in the compatibility chart.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | Various | 40 | 2-Stroke | 1995–2005 | 6H3-W0078-02-00 | |
| Yamaha | Various | 50 | 2-Stroke | 1998–2009 | 6H3-W0078-02-00 | |
| Yamaha | Various | 40 | 4-Stroke | 1998 | 63D-W0078-01 | Alternative part |
| Yamaha | Various | 50 | 4-Stroke | 1995–2009 | 63D-W0078-01 | Alternative part |
| Yamaha | Various | 60 | 4-Stroke | 2002–2009 | 63D-W0078-01 | Alternative part |
| Yamaha | T50 | 50 | 4-Stroke | 2006+ | 6H3-W0078-02-00 | High Thrust model |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct Replacement
- Other Technical Attributes
- Includes complete water pump service components
What’s in the Box
- 1 x Cartridge Insert (663-44322-00-00)
- 1 x Impeller (6H3-44352-00-00)
- 1 x Water Pump Gasket 1 (6H3-44315-A0-00)
- 1 x Cartridge Outer Plate (6H3-44323-00-00)
- 1 x Cartridge Gasket (6H3-44324-A0-00)
- 1 x Water Pump Gasket 2 (688-44316-A0-00)
- 1 x O-Ring (93210-46044-00)
- 2 x Bolts, With Washer (90119-08M14-00)
- 2 x Bolts, With Washer (90119-08M33-00)
- 1 x Woodruff Key (90280-03M03-00)
Installation Notes
- Disconnect the negative battery cable and remove the engine cover.
- Shift the outboard into neutral and remove the lower unit mounting bolts.
- Carefully separate the lower unit (gearcase) from the upper driveshaft housing.
- Locate and unbolt the water pump housing cover to expose the old impeller.
- Remove the old impeller, gaskets, wear plate, and seals, noting their orientation.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new components from the kit in the reverse order of removal, starting with the new plate and gaskets.
- Apply a light coat of marine grease to the new impeller and the inside of the pump housing.
- Align the new impeller with the Woodruff key and slide it onto the driveshaft, rotating clockwise to seat the vanes.
- Reinstall the pump housing, tighten bolts to the manufacturer-specified torque, and reattach the lower unit.
- Reconnect the battery and test the engine in water, confirming a strong stream from the water pump tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my specific Yamaha model?
This kit fits most Yamaha 40-50 HP 2-stroke (1995–2009) and 40-60 HP 4-stroke (1995–2009) outboards. To ensure a perfect match, always check the OEM part number listed for your specific engine model and year against our Part Number Matrix and Compatibility table.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating at idle or low speeds, a weak or intermittent stream of water from the "tell-tale" outlet, and a noticeably brittle, cracked, or deformed impeller during a visual inspection.
How often should I replace my outboard's water pump impeller?
For preventative maintenance, it is recommended to replace the impeller every one to two years, or every 100-200 hours of use. More frequent replacement may be necessary if you operate primarily in saltwater or sandy/silty conditions.
Why does my engine overheat even after installing the new kit?
If overheating persists, check for other blockages in the cooling system, such as clogged intake screens, thermostat issues, or debris in the water passages. Ensure all gaskets were seated correctly and the housing bolts were torqued properly to prevent air leaks.
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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