Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-00, 6H3-W0078-02-00)
Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-00, 6H3-W0078-02-00) 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 Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-...
Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-00, 6H3-W0078-02-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit – Fits Yamaha 50 60 70 HP Outboards is designed for a wide range of Yamaha outboards, including 2-stroke 50–70 HP models (1984–2003) and 4-stroke 40–60 HP models (1999–2019). It provides all necessary components for a complete water pump service to maintain your engine’s cooling system.
This kit serves as a direct interchange for multiple OEM and aftermarket part numbers, including the Yamaha 6H3-W0078 series, Sierra 18-3464 series, and GLM 12057/12283.
- Installs in the lower unit gearcase to restore cooling system performance.
- Impeller is made from durable, high-performance CR Neoprene rubber for reliability.
- Includes essential hardware like a Woodruff key, gaskets, and bolts for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6H3-W0078-00 |
| Yamaha | 6H3-W0078-02 |
| Yamaha | 6H3-W0078-A0-00 |
| Sierra | 18-3464 |
| Sierra | 18-3465 |
| Sierra | 18-3466 |
| GLM | 12057 |
| GLM | 12283 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 60 | 60 HP | 2-Stroke | 2001–2003 | 6H3-W0078-02 | |
| Yamaha | 60 | 60 HP | 2-Stroke | 2004–2005 | 692-W0078-02 | Superseded part |
| Yamaha | C60 | 60 HP | 2-Stroke | 1996–2001 | 6H3-W0078-02 | |
| Yamaha | E60 | 60 HP | 2-Stroke | 1995–1996 | 6H3-W0078-02 | |
| Yamaha | P60 | 60 HP | 2-Stroke | 1991 | 6H3-W0078-02 | |
| Yamaha | P60 | 60 HP | 2-Stroke | 1992–1999 | 6H3-W0078-02 | |
| Yamaha | 70 | 70 HP | 2-Stroke | 1984–2003 | 6H3-W0078-02 | |
| Yamaha | C70 | 70 HP | 2-Stroke | 2000–2001 | 6H3-W0078-02 | |
| Yamaha | F40 | 40 HP | 4-Stroke | 1999 | 6H3-W0078-02 | |
| Yamaha | F50 | 50 HP | 4-Stroke | 1997 | 6H3-W0078-02 | |
| Yamaha | FT50 | 50 HP | 4-Stroke | 1997–2017 | 6H3-W0078-02 | |
| Yamaha | FT60 | 60 HP | 4-Stroke | 2002–2017 | 6H3-W0078-02 | |
| Yamaha | T50 | 50 HP | 4-Stroke | 1996 | 6H3-W0078-02 |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Lower Unit Gearcase
- Housing Material
- Nylon PA66 Plastic (housing), Stainless Steel (plate/cup)
- Housing Color
- White/Beige
- Impeller Material
- CR Neoprene Rubber
- Weight
- 0.24 kg (8.7 oz)
- Warranty
- Manufacturer dependent, typically 1 year
What’s in the Box
- 1 x Water Pump Impeller (6H3-44352-00-00)
- 1 x Woodruff Key (90280-03M03-00)
- 1 x Cartridge Insert (663-44322-00-00)
- 1 x Cartridge Outer Plate (6H3-44323-00-00)
- 1 x Cartridge Gasket (6H3-44324-A0-00)
- 1 x Water Pump Gasket (6H3-44315-A0-00)
- 1 x Water Pump Gasket (688-44316-A0-00)
- 1 x O-Ring (93210-46044-00)
- 2 x Bolt With Washer (90119-08M14-00)
- 2 x Bolt With Washer (90119-08M33-00)
Installation Notes
- Disconnect the battery and shift the outboard into the neutral position.
- Carefully remove the bolts securing the lower unit (gearcase) and detach it from the upper housing.
- Unscrew the bolts on the water pump housing and remove the old housing, impeller, and gaskets.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new Woodruff key on the driveshaft and slide the new impeller on, turning it in the direction of engine rotation.
- Place the new gaskets, insert cartridge, and outer plate according to the service manual diagram.
- Secure the new water pump housing with the provided bolts, tightening them to the manufacturer's specified torque.
- Carefully guide the driveshaft and water tube while reinstalling the lower unit, ensuring everything aligns correctly.
- Reinstall and tighten the lower unit mounting bolts.
- Reconnect the battery, start the engine in water, and confirm a strong, steady stream from the cooling system's tell-tale port.
Troubleshooting & FAQ
How do I know if this kit fits my Yamaha outboard?
To ensure compatibility, check your engine’s model, horsepower, and year against the detailed "Engine & Model Compatibility" table. This kit is specifically for Yamaha 2-stroke 50–70 HP (1984–2003) and 4-stroke 40–60 HP (1999–2019) models listed. Cross-referencing your engine's OEM part number is the best way to confirm fitment.
What are the signs of a failed water pump impeller?
Common signs include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet port, and a melted water pump housing. During a physical inspection, a worn impeller may have brittle, cracked, or broken vanes.
How often should I replace my water pump impeller?
As a best practice, we recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of use. Replacement intervals should be shorter for boats operated in saltwater or sandy/silty conditions.
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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