Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-02-00, 6H3-W0078-A0-00)
Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-02-00, 6H3-W0078-A0-00) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller Kit – Fits Yamaha 50-70 HP (Replaces 6H3-W0078-02-00, 6H3-W0078-A0-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-02-00, 6H3-W0078-A0-00) provides a complete solution for servicing the water pump on compatible Yamaha 2-Stroke 60–70 HP (1992–2003) and 4-Stroke T50/FT50/T60/FT60 (1997–UP) outboard motors.
It is a direct interchange for Yamaha part numbers 6H3-W0078-00-00, 6H3-W0078-A0-00, 6H3-W0078-02-00, 6H3-44311-00-00, and Sierra aftermarket parts 18-3461 and 18-3466.
- Engineered for direct replacement installation.
- Complete kit includes the housing, impeller, plate, and gaskets.
- Constructed with a durable neoprene impeller and corrosion-resistant SS316 stainless steel insert cup.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6H3-W0078-00-00 |
| Yamaha | 6H3-W0078-A0-00 |
| Yamaha | 6H3-W0078-02-00 |
| Yamaha | 6H3-44311-00-00 |
| Sierra | 18-3461 |
| Sierra | 18-3466 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is compatible with the following Yamaha 2-Stroke models:
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 60F | 60 | 2-Stroke | 1997–2003 | 6H3-W0078-02-00 | |
| Yamaha | P60 | 60 | 2-Stroke | 1992–1999 | 6H3-W0078-02-00 | |
| Yamaha | E60 | 60 | 2-Stroke | 1995–1996 | 6H3-W0078-02-00 | |
| Yamaha | C60 | 60 | 2-Stroke | 1996–2001 | 6H3-W0078-02-00 | |
| Yamaha | 70 | 70 | 2-Stroke | 1992–2003 | 6H3-W0078-02-00 | |
| Yamaha | 70B | 70 | 2-Stroke | 1997–2003 | 6H3-W0078-02-00 | |
| Yamaha | C70 | 70 | 2-Stroke | 2000–2001 | 6H3-W0078-02-00 |
This kit is compatible with the following Yamaha 4-Stroke models:
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | T50 | 50 | 4-Stroke | 1997–2010 | 6H3-W0078-02-00 | |
| Yamaha | FT50B | 50 | 4-Stroke | 1997–2002 | 6H3-W0078-02-00 | |
| Yamaha | FT50C | 50 | 4-Stroke | 2003–2007 | 6H3-W0078-02-00 | |
| Yamaha | FT50G | 50 | 4-Stroke | 2005–2012 | 6H3-W0078-02-00 | |
| Yamaha | FT50J | 50 | 4-Stroke | 2013–UP | 6H3-W0078-02-00 | |
| Yamaha | T60 | 60 | 4-Stroke | 2003–2010 | 6H3-W0078-02-00 | |
| Yamaha | FT60B | 60 | 4-Stroke | 2003–2006 | 6H3-W0078-02-00 | |
| Yamaha | FT60D | 60 | 4-Stroke | 2005–2012 | 6H3-W0078-02-00 | |
| Yamaha | FT60G | 60 | 4-Stroke | 2013–UP | 6H3-W0078-02-00 |
Technical Specs
- Product Type
- Water Pump Impeller Kit with Housing
- Installation
- Direct replacement
- Housing Material
- Nylon PA66 Plastic
- Housing Color
- Black
- Impeller Material
- Neoprene
- Insert Cup Material
- SS316 Stainless Steel
- Weight
- 0.65 lbs (0.29 kg)
- Other Technical Attributes
- Includes SS316 Insert Cup and Plate
What’s in the Box
- 1 x Water Pump Gasket (688-44316-01-00/688-44316-A0-00)
- 1 x Water Pump Gasket (6H2-44315-00-00/6H2-44315-A0-00)
- 1 x Outer Plate Gasket (6H2-44324-00-00/6H2-44324-A0-00)
- 1 x Wear Plate (6H3-44323-00-00)
- 1 x Impeller (6H2-44352-00-00)
- 1 x Impeller Key (90280-03M03-00/90280-03M07-00)
- 1 x Insert Cup (663-44322-00-00)
- 1 x O-Ring (93210-46044-00)
- 1 x Water Pump Housing (6H2-44311-00-00)
- 2 x Bolt with washer (90119-08M14-00)
- 2 x Bolt with washer (90119-08M33-00)
Installation Notes
- Disconnect the negative battery cable and remove the propeller.
- Place a drain pan under the lower unit and remove the gear oil drain/fill plugs to drain the fluid.
- Remove the bolts securing the lower unit (gearcase) to the upper engine housing and carefully separate the two sections.
- Unbolt and remove the old water pump housing to access the impeller, wear plate, and gaskets. Note the orientation of all parts during removal.
- Thoroughly clean all mating surfaces, removing any traces of old gasket material or debris.
- Install the new wear plate, gaskets, impeller key, and impeller. Ensure the impeller key locks the impeller to the driveshaft.
- Lubricate the inside of the new housing and the new impeller with a light coat of marine grease.
- Install the new insert cup and O-ring into the housing.
- Slide the new housing down over the impeller while turning the driveshaft clockwise to seat the impeller vanes correctly.
- Secure the new housing with the provided bolts and reassemble the lower unit to the upper housing.
- Refill the gearcase with fresh marine gear oil to the proper level.
- Reconnect the battery, start the engine in water, and immediately check for a strong, steady water stream from the engine's tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this kit fits my specific engine?
Verify your engine's model, HP, and year against the detailed compatibility tables provided on this page. For best results, also cross-reference the part number stamped on your original components with the numbers listed in our Part Number Matrix.
What are the signs of a worn or failing water pump impeller?
Common symptoms include a weak or intermittent water stream from the engine's tell-tale outlet, engine overheating alarms, steam from the exhaust, or a noticeable drop in engine performance, especially at higher RPMs.
How often should I replace my outboard's water pump impeller?
For preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1 to 2 years, or every 100-200 hours of operation. Service intervals should be shorter for boats used in saltwater or in water with heavy sediment.
What makes this kit a complete solution?
This kit includes not only the impeller and gaskets but also the water pump housing, wear plate, insert cup, O-ring, and mounting bolts. This ensures you have all the necessary components for a full service, which is often not the case with basic impeller-only kits.
What is the difference between an OEM and an aftermarket part?
This is an aftermarket replacement part, not sourced from the original equipment manufacturer (OEM). It is engineered to meet or exceed OEM specifications for fit, form, and function, using comparable materials. Our parts are made in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.
How fast do you ship and what does it cost?
We offer fast worldwide shipping, with typical transit times of 5–15 days for most regions. Standard shipping is free on all orders. Expedited shipping options, if available for your location, will be presented at checkout.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal marine use. Should you encounter an issue, please contact our support team with your order details. We accept returns for unused items in their original condition within our standard return window. For detailed instructions, please see our full policy page or contact us directly.
Safety & Important Info
- Verify all images and specifications against your original part before purchasing. If any detail differs—even if your model is listed as compatible—do not order the part.
- This product is an aftermarket replacement part, not an Original Equipment Manufacturer (OEM) component.
- Professional installation by a qualified marine mechanic is highly recommended to ensure safety and proper performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.
- Fast Global Fulfillment — We provide free standard delivery to most regions, with an average transit time of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we offer fair pricing without ever compromising on material quality or QC standards.
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