Water Pump Impeller Repair Kit – Fits Yamaha, Mariner 6-8 HP 2-Stroke (Replaces 6N0-W0078-A0-00, 6G1-W0078-A1-00)
Water Pump Impeller Repair Kit – Fits Yamaha, Mariner 6-8 HP 2-Stroke (Replaces 6N0-W0078-A0-00, 6G1-W0078-A1-00) 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
Free standard shipping on all orders under 1 KG
Water Pump Impeller Repair Kit – Fits Yamaha, Mariner 6-8 HP 2-Stro...
Product Details
This Water Pump Impeller Repair Kit – Fits Yamaha 6/8 HP 2-Stroke Outboards provides a comprehensive solution for servicing the cooling system on select Yamaha and Mariner 2-stroke engines. It is engineered for Yamaha 6 HP and 8 HP models from 1984 through 1996 (including 6C, 6D, 6J, 8C, 8J, and 8N series) and Mariner 6 HP and 8 HP models from 1984 through 1986 (6C, 6D, 8C series), ensuring optimal water flow to prevent overheating.
It serves as a direct interchange for Yamaha part numbers 6N0-W0078-A0-00, 6G1-W0078-A1-00, 6G1-W0078-00-00, and 6G1-W0078-01-00, as well as Sierra 18-3460.
- Installation requires servicing the lower unit.
- Kit includes a durable neoprene impeller and all necessary gaskets, plates, and bolts.
- Engineered for direct-fit replacement of the original pump components.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6N0-W0078-A0-00 |
| Yamaha | 6G1-W0078-A1-00 |
| Yamaha | 6G1-W0078-00-00 |
| Yamaha | 6G1-W0078-01-00 |
| Sierra | 18-3460 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is compatible with a wide range of Yamaha 6 HP and 8 HP 2-stroke models. Note that earlier models (1984–1996) typically use the 6G1-W0078 series reference, while later models (1997+) use 6N0-W0078-A0-00.
Fits select Mariner 6C, 6D, and 8C models manufactured by Yamaha between 1984 and 1986.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 6MLHV | 6 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | |
| Yamaha | 6MLHW | 6 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | |
| Yamaha | 6MLHX | 6 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | |
| Yamaha | 6MLHY | 6 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | |
| Yamaha | 6MSHV | 6 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | |
| Yamaha | 6MSHW | 6 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | |
| Yamaha | 6MSHX | 6 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | |
| Yamaha | 6MSHY | 6 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | |
| Yamaha | 8MLHV | 8 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | |
| Yamaha | 8MLHW | 8 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | |
| Yamaha | 8MLHX | 8 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | |
| Yamaha | 8MLHY | 8 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSH | 8 | 2-Stroke | 2004–2009 | 6N0-W0078-A0-00 | Multiple year codes: 0405, 0406, 0407, 0608, 0709 |
| Yamaha | 8MSHA | 8 | 2-Stroke | 2002 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHB | 8 | 2-Stroke | 2003 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHC | 8 | 2-Stroke | 2004 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHD | 8 | 2-Stroke | 2005 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHV | 8 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHW | 8 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHX | 8 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHY | 8 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | |
| Yamaha | 8MSHZ | 8 | 2-Stroke | 2001 | 6N0-W0078-A0-00 | |
| Yamaha | 6C, 6D, 6J | 6 | 2-Stroke | 1984–1996 | 6G1-W0078-A1-00 | Earlier models use 6G1-series part numbers |
| Yamaha | 8C, 8J, 8N | 8 | 2-Stroke | 1984–1996 | 6G1-W0078-A1-00 | Earlier models use 6G1-series part numbers |
| Mariner | 6C | 6 | 2-Stroke | 1984–1986 | Mercury/Mariner reference | |
| Mariner | 6D | 6 | 2-Stroke | 1984–1986 | Mercury/Mariner reference | |
| Mariner | 8C | 8 | 2-Stroke | 1984–1986 | Mercury/Mariner reference |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Lower Unit Service
- Connection
- Direct Fit
- Fitting Type
- Direct Fit
- Warranty
- 1 Year (JLM Marine)
- Other Technical Attributes
- Neoprene impeller material (some aftermarket variants)
What’s in the Box
- 1 x Water Pump Gasket (6G1-44315-A0-00)
- 1 x Cartridge Insert (6G1-44322-00-00/6G1-44322-02-00)
- 1 x Cartridge Outer Plate (6G1-44323-00-00)
- 1 x Water Seal Damper (647-44366-00-00)
- 1 x Impeller (6G1-44352-00-00)
- 1 x Plate Kit (6G1-44328-00-00)
- 4 x Bolts (97080-06405-00)
Installation Notes
- Disconnect the battery and shift the outboard into neutral.
- Remove the bolts securing the lower unit (gearcase) to the upper casing.
- Carefully lower the gearcase, being mindful of the shift shaft linkage.
- Unbolt and remove the old water pump housing assembly.
- Clean the driveshaft and mounting surfaces, removing any old gasket material or sealant.
- Assemble the new kit components. Install the new gaskets, wear plate, and impeller. Ensure the impeller vanes are oriented correctly (typically by turning the driveshaft clockwise during installation).
- Re-install the water pump housing and torque bolts to manufacturer specifications.
- Re-attach the lower unit, ensuring the shift shaft, water tube, and driveshaft align correctly before tightening.
- After securing the lower unit, test the engine using a water source (flushing muffs or in water) to confirm proper cooling system operation.
Troubleshooting & FAQ
My Yamaha is a 1996/1997 model. Which part number is correct?
There can be an overlap in these years. Yamaha models from 1984–1996 generally use the 6G1 series part number (6G1-W0078-A1-00), while models from 1997 onwards often use 6N0-W0078-A0-00. This kit is designed to replace both. The best practice is to verify by visually matching your old pump components to our product photos before ordering.
What are the signs of a failing water pump impeller?
Common signs include a weak or non-existent water stream from the "tell-tale" port, engine overheating alarms, steam from the exhaust, and reduced engine performance. It is a critical maintenance item that should be replaced every 1-2 years or 100-200 hours of use, especially in saltwater environments.
Will this fit my Mariner outboard?
This kit is listed as compatible with Mariner 6C, 6D, and 8C models from 1984 to 1986, which were manufactured by Yamaha. However, we strongly recommend cross-referencing your part numbers and visually inspecting your old pump components before ordering to guarantee fitment.
What is the difference between the various Yamaha part numbers this kit replaces?
The part numbers 6G1-W0078-00-00, 6G1-W0078-01-00, and 6G1-W0078-A1-00 are earlier versions or supersessions for the same group of engines. The 6N0-W0078-A0-00 is the reference for slightly later models. This aftermarket kit contains all the necessary components to service the pumps covered by all these equivalent numbers.
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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