Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-01-00)
Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-01-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H...
Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-01-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards provides all essential components to restore your engine's cooling system. It is designed for a precise fit on Yamaha 2-Stroke 60-70 HP (1992–2003) and 4-Stroke High Thrust 50 HP (1997–2012) and 60 HP (2003–2012) models, ensuring reliable performance and engine longevity.
This kit serves as a direct replacement for OEM part numbers 6H3-W0078-01-00, 6H3-W0078-02-00, and 6H3-W0078-A0-00, and is an aftermarket equivalent for Sierra 18-3465, 18-3466 (with housing), UanofCn 6H3-W0078-02-00, and others.
- Installs as a direct replacement for the original factory parts.
- Features a durable neoprene rubber impeller for optimal water flow and longevity.
- Some variations of this kit include the Nylon PA66 housing and SS316 wear plate for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6H3-W0078-01-00 | Superseded by 6H3-W0078-02-00 |
| Yamaha | 6H3-W0078-02-00 | Current OEM part number |
| Yamaha | 6H3-W0078-A0-00 | Used on earlier models (pre-1992) |
| Sierra | 18-3465 | Aftermarket kit without housing |
| Sierra | 18-3466 | Aftermarket kit with housing |
| Sierra | 18-3428-1 | Aftermarket cross-reference |
| Sierra | 18-3461 | Aftermarket cross-reference |
| UanofCn | 6H3-W0078-02-00 | Aftermarket cross-reference |
| GHmarine | 6H3W0078 | Aftermarket cross-reference |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit fits the following Yamaha 2-Stroke outboard models:
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 60F | 60 HP | 2-Stroke | 1997–2003 | 6H3-W0078-02-00 | |
| Yamaha | C60 | 60 HP | 2-Stroke | 1996–2001 | 6H3-W0078-02-00 | |
| Yamaha | E60 | 60 HP | 2-Stroke | 1995–1996 | 6H3-W0078-02-00 | |
| Yamaha | P60 | 60 HP | 2-Stroke | 1992–1999 | 6H3-W0078-02-00 | |
| Yamaha | 70B | 70 HP | 2-Stroke | 1997–2003 | 6H3-W0078-02-00 | |
| Yamaha | C70 | 70 HP | 2-Stroke | 2000–2001 | 6H3-W0078-02-00 | |
| Yamaha | 70 | 70 HP | 2-Stroke | 1992–2003 | 6H3-W0078-02-00 | Earlier models (1984–1991) used 6H3-W0078-A0-00 |
This kit fits the following Yamaha 4-Stroke High Thrust outboard models:
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | T50 | 50 HP | 4-Stroke | 1997–2010 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT50B | 50 HP | 4-Stroke | 1997–2002 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT50C | 50 HP | 4-Stroke | 2003–2007 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT50G | 50 HP | 4-Stroke | 2005–2012 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT50J | 50 HP | 4-Stroke | 2013–later | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | T60 | 60 HP | 4-Stroke | 2003–later | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT60B | 60 HP | 4-Stroke | 2003–2006 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT60D | 60 HP | 4-Stroke | 2005–2012 | 6H3-W0078-02-00 | High Thrust Model |
| Yamaha | FT60G | 60 HP | 4-Stroke | 2013–later | 6H3-W0078-02-00 | High Thrust Model |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct replacement
- Housing Material
- Some kits include: Nylon PA66 (Housing), SS316 (Insert Cup and Plate)
- Housing Color
- Black
- Weight
- 0.65 pounds (0.29 kg)
- Impeller Material
- Neoprene rubber
What’s in the Box
- 1 x Water Pump Impeller (6H3-44352-00-00)
- 1 x Key, Woodruff (90280-03M03-00)
- 1 x Gasket, Water Pump (6H3-44315-A0-00)
- 2 x Bolt (97095-08045-00)
- 1 x Gasket, Water Pump (688-44316-A0-00)
- 1 x Gasket, Outer Plate (6H3-44324-A0-00)
- 1 x Cup, Impeller (663-44322-00-00)
- 1 x O-Ring (93210-46044-00)
- 2 x Bolt (97395-08055-00)
- 1 x Plate, Wear (6H3-44323-00-00)
Note: Some kits may also include a Water Pump Housing (6H3-44311-00-00) as specified in Sierra 18-3466 and similar kits.
Installation Notes
- Disconnect the negative battery cable and remove the engine cover.
- Place a drain pan under the lower unit and remove the gearcase drain screw to empty the gear lube.
- Shift the engine into neutral and unbolt the lower unit (gearcase) from the engine's midsection.
- Carefully lower the gearcase to expose the water pump assembly on top of it.
- Remove the bolts securing the water pump housing.
- Lift the housing off and take note of the orientation of the impeller, key, and gaskets.
- Remove the old impeller, woodruff key, wear plate, and all gaskets.
- Thoroughly clean all mating surfaces, ensuring they are free of old gasket material and corrosion.
- Install the new components from the kit in reverse order. Lightly grease the new wear plate, cup, and impeller. When installing the impeller, turn the driveshaft clockwise to bend the vanes into the correct position.
- Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
- Reattach the lower unit, ensuring the driveshaft, shift shaft, and water tube align properly.
- Refill the gearcase with fresh lubricant, start the engine with a proper water supply (flushing muffs), and confirm a steady stream of water from the tell-tale port.
Troubleshooting & FAQ
How do I know if this kit fits my specific Yamaha model?
This kit is designed for a wide range of Yamaha 50-70 HP outboards, but it's critical to verify your exact model and year. Please refer to our detailed "Engine & Model Compatibility" tables above. Cross-reference your engine's model number and production year to ensure a perfect match before ordering.
What is the difference between kits with and without a housing?
This standard kit (replaces 6H3-W0078-02-00) contains the impeller, gaskets, and wear parts for a typical service. Kits that include a new pump housing (like Sierra 18-3466) are recommended if your original housing is cracked, warped from overheating, or heavily corroded.
How often should I replace my water pump impeller?
For preventative maintenance, we recommend replacing the impeller every one to two years, or every 100-200 hours of engine use. Service intervals should be shorter for boats operated in saltwater or in water with high levels of sand or silt.
What are the signs of a failing water pump?
Common symptoms include a weak or intermittent water stream from the tell-tale outlet, an engine overheating alarm sounding, steam from the exhaust, or a noticeable drop in water pressure on a dash gauge.
Is it necessary to replace the woodruff key and wear plate?
Yes. The kit includes a new woodruff key to ensure a tight, slip-free fit on the driveshaft. The wear plate and cup provide a fresh, smooth surface for the new impeller to seal against, which is critical for achieving proper water pressure. Always use all new components provided in the kit.
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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