Water Pump Impeller Kit – Fits Yamaha 25-50 HP (Replaces 6H4-44352, 6H4-W0078-00)
Water Pump Impeller Kit – Fits Yamaha 25-50 HP (Replaces 6H4-44352, 6H4-W0078-00) is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Kit – Fits Yamaha 25-50 HP (Replaces 6H4-44352,...
Water Pump Impeller Kit – Fits Yamaha 25-50 HP (Replaces 6H4-44352, 6H4-W0078-00) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Pump Impeller Kit is a direct-fit replacement for a wide range of Yamaha outboard motors. It is designed for various 2-stroke models including 25 HP (1996–2002), 30 HP (1987–2001), 40 HP (1984–1994), and 50 HP (1984–1994), as well as 4-stroke models F20-F40 manufactured between 1998 and 2011.
This component provides a direct interchange for Yamaha impeller part numbers 6H4-44352-00/01/02 and the impeller within kit 6H4-W0078-00. It also cross-references with aftermarket parts from Sierra (18-3415/18-3434) and GLM (12276).
- Engineered for direct OEM replacement to ensure straightforward installation.
- Impeller is manufactured from durable, marine-grade rubber for longevity.
- Produced in an ISO9002 certified facility to meet high-quality standards.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Yamaha | 6H4-44352-00, 6H4-44352-01, 6H4-44352-02 |
| Yamaha (Full Kit) | 63D-W0078-00-00, 63D-W0078-01-00, 63D-W0078-02-00, 63D-W0078-03-00 |
| Sierra | 18-3415, 18-3434 |
| GLM | 12276 |
Engine & Model Compatibility
Confirm your engine model and year in the tables below.
This impeller fits the following Yamaha 2-Stroke and 4-Stroke outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 25B, 25J, 25N, 25Q, 25V, 25XMH | 25 | 2-Stroke | 1996–2002 | 6H4-44352-02 | 3-cylinder engines |
| Yamaha | C30, 30D, 30G, 30H | 30 | 2-Stroke | 1987–2001 | 6H4-44352-02 | |
| Yamaha | 40H, 40X | 40 | 2-Stroke | 1984–1994 | 6H4-44352-02 | |
| Yamaha | 50D | 50 | 2-Stroke | 1984–1994 | 6H4-44352-02 | |
| Yamaha | F20A, F20D | 20 | 4-Stroke | 1998–2011 | 6H4-44352-02 | |
| Yamaha | F25A, F25D | 25 | 4-Stroke | 1998–2011 | 6H4-44352-02 | |
| Yamaha | FT25B, FT25F | 25 | 4-Stroke | 2001–2006 | 6H4-44352-02 | |
| Yamaha | F30A, F30B | 30 | 4-Stroke | 2001–2005 | 6H4-44352-02 | |
| Yamaha | F40B, F40F | 40 | 4-Stroke | 2000–2008 | 6H4-44352-02 |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct OEM replacement
- Material
- Marine-grade rubber (impeller); aluminum/stainless steel (housing components)
- Dimensions
- Impeller dimensions: 51.2 mm (outer diameter) × 16.1 mm (inner diameter) × 19.05 mm (height)
- Certification
- Produced in ISO9002 certified factory
What’s in the Box
- 1 x Water Pump Impeller (replaces 6H4-44352-02)
- Note: This product contains the impeller only. For the complete water pump repair kit with housing, please reference Yamaha part number 6H4-W0078-00.
Installation Notes
- Disconnect the battery before starting work.
- Remove the lower unit (gearcase) from the outboard motor.
- Unbolt and remove the water pump housing to access the old impeller.
- Remove the old impeller and the Woodruff key from the driveshaft.
- Clean the interior of the housing and inspect it and the wear plate for scoring or damage. Replace if necessary.
- Install the new Woodruff key and slide the new impeller onto the driveshaft, turning it clockwise to bed the vanes.
- Re-install the water pump housing, ensuring any gaskets or o-rings are properly seated.
- Re-attach the lower unit to the outboard and torque bolts to manufacturer specifications.
- Start the engine in water and confirm a steady stream from the "tell-tale" outlet.
Troubleshooting & FAQ
How do I know if this impeller fits my Yamaha outboard?
First, check your engine model, horsepower, and year against the detailed compatibility table on this page. Second, it is always best practice to visually compare our product photos with your existing part before ordering to ensure an exact match.
What are the signs of a failing water pump impeller?
The most common symptoms are engine overheating at idle or low speeds and a weak or non-existent water stream from the "tell-tale" indicator. Upon inspection, a worn impeller may have cracked, brittle, or permanently curved vanes.
How often should I replace my water pump impeller?
As a crucial part of preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of operation. Service intervals should be shorter in saltwater or silty conditions.
Does this kit include the housing, gaskets, or wear plate?
No, this listing is for the flexible rubber impeller only, which corresponds to Yamaha part number 6H4-44352-02. For a complete service kit that includes the housing, gaskets, and plate, please look for Yamaha kit number 6H4-W0078-00.
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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