Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25–30 HP (Replaces 689-W0078-A4-00, 689-W0078-04-00)
Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25–30 HP (Replaces 689-W0078-A4-00, 689-W0078-04-00) 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 Impeller Kit – Fits Yamaha 2-Stroke 25–30 HP (Replaces 6...
Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25–30 HP (Replaces 689-W0078-A4-00, 689-W0078-04-00) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit – Fits Yamaha 2-Stroke 25–30 HP Outboard Engines is a comprehensive, direct-fit solution for maintaining the cooling system on several Yamaha 2-stroke outboard models. It is designed for specific 25 HP (1986–1997) and 30 HP (1986–1992) series engines, including C25, C30, CV25, and CV30 variants, ensuring reliable performance.
The kit serves as a direct interchange for Yamaha part numbers 689-W0078-A4-00, 689-W0078-06-00, 689-W0078-05-00, and 689-W0078-A6-00, as well as aftermarket equivalents like Sierra Marine 18-3426, 18-3427, and Mercury 47-42431M / 47-84829M.
- Engineered for direct replacement of the original water pump assembly.
- Constructed from marine-grade metal and durable CR Neoprene rubber for longevity in saltwater and freshwater environments.
- Includes all essential components for a complete overhaul, including the impeller, housing, plates, and gaskets.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 689-W0078-A4-00 | OEM Reference |
| Yamaha | 689-W0078-04-00 | OEM Reference |
| Yamaha | 689-W0078-05-00 | OEM Reference |
| Yamaha | 689-W0078-06-00 | OEM Reference |
| Yamaha | 689-W0078-A6-00 | OEM Reference |
| Sierra Marine | 18-3426 | Aftermarket Interchange |
| Sierra Marine | 18-3427 | Aftermarket Interchange |
| Mercury | 47-42431M | Aftermarket Interchange |
| Mercury | 47-84829M | Aftermarket Interchange |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is verified to fit the following Yamaha outboard models. Please check your specific model and year range before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Yamaha | 25 | 25 | 2-Stroke | 1986–1987 | 689-W0078-A4-00 |
| Yamaha | C25 | 25 | 2-Stroke | 1991–1997 | 689-W0078-A4-00 |
| Yamaha | 30 | 30 | 2-Stroke | 1986 | 689-W0078-A4-00 |
| Yamaha | C30 | 30 | 2-Stroke | 1991–1992 | 689-W0078-A4-00 |
| Yamaha | CV25 | 25 | 2-Stroke | 1990 | 689-W0078-A4-00 |
| Yamaha | CV30 | 30 | 2-Stroke | 1989–1990 | 689-W0078-A4-00 |
| Yamaha | C25ELRU | 25 | 2-Stroke | 1996 | 689-W0078-A6-00 |
| Yamaha | C25ELRV | 25 | 2-Stroke | 1997 | 689-W0078-A6-00 |
| Yamaha | C25ELHU | 25 | 2-Stroke | 1996 | 689-W0078-A6-00 |
| Yamaha | C25ELHV | 25 | 2-Stroke | 1997 | 689-W0078-A6-00 |
| Yamaha | C25MLHU | 25 | 2-Stroke | 1996 | 689-W0078-A6-00 |
| Yamaha | C25MSHU | 25 | 2-Stroke | 1996 | 689-W0078-A6-00 |
| Yamaha | C25MLHV | 25 | 2-Stroke | 1997 | 689-W0078-A6-00 |
| Yamaha | C25MSHV | 25 | 2-Stroke | 1997 | 689-W0078-A6-00 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct replacement
- Housing Material
- Marine-grade metal (housing), CR Neoprene Rubber (impeller)
- Housing Color
- Silver/Gray
- Weight
- 236–285 g (8.4–10.1 oz)
What’s in the Box
- 1 x Water Pump Impeller (689-44352-02-00)
- 1 x Woodruff Key (664-44338-00-00)
- 1 x Water Pump Housing (689-44311-03-00)
- 1 x Insert Cartridge (689-W4432-01-00/689-W4432-02-00)
- 1 x Wear Plate/Cartridge Outer Plate (689-44323-02-00/689-44323-03-00)
- 1 x Cartridge Gasket (689-44324-A0-00)
- 1 x Water Pump Gasket (689-44316-A0-00)
- 1 x Water Seal Damper (626-44365-01-00/626-44365-02-00)
- 3 x Bolt with Washer (97080-06030-00/90119-06M07-00)
Installation Notes
- Disconnect the battery and shift the outboard to neutral.
- Drain the gearcase lubricant and cooling system.
- Remove the lower unit (gearcase) from the outboard's driveshaft housing.
- Unbolt and remove the old water pump housing to access the impeller.
- Carefully note the orientation of the old components before removing them.
- Clean the mounting surfaces and inspect the driveshaft for any wear or damage.
- Install the new Woodruff key, impeller, wear plate, and gaskets as provided in the kit. Ensure the impeller vanes are oriented correctly (typically turning clockwise during installation).
- Securely fasten the new water pump housing and insert cartridge.
- Reinstall the lower unit, refill the gearcase with the correct oil, and reconnect all components.
- Once assembled, start the engine at idle and confirm a steady stream of water from the cooling system's tell-tale outlet.
Troubleshooting & FAQ
How do I know if this kit fits my Yamaha engine?
This kit is specifically designed for Yamaha 2-stroke 25 HP (1986–1997) and 30 HP (1986–1992) models, including the C25, C30, CV25, and CV30 series. Always verify your engine's model and year against our compatibility table before purchase.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating, a weak or nonexistent water stream from the tell-tale outlet, or visible damage such as cracks, stiffness, or missing vanes on the old impeller upon inspection.
How often should I replace my water pump impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or after 100-200 hours of operation. Replacement intervals should be shorter in saltwater or silty/sandy conditions.
Is the pump housing included in this kit?
Yes, this is a complete repair kit that includes the water pump housing, insert cartridge, wear plate, impeller, and all necessary gaskets, seals, and bolts for a full replacement.
Why do some parts list multiple part numbers?
This indicates that the component in the kit is a direct replacement for several OEM part numbers, which may include original parts and their subsequent supersessions. The part is designed to fit all listed variations.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and quality control.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against 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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