Water Pump Impeller Repair Kit for Yamaha and Mariner 6–8 HP 2-Stroke Outboards — Replaces 6N0-W0078-A0-00 and 6G1-W0078-A1-00
Water Pump Impeller Repair Kit for Yamaha and Mariner 6–8 HP 2-Stroke Outboards — Replaces 6N0-W0078-A0-00 and 6G1-W0078-A1-00 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Pump Impeller Repair Kit for Yamaha and Mariner 6–8 HP 2-Stro...
Water Pump Impeller Repair Kit for Yamaha and Mariner 6–8 HP 2-Stroke Outboards — Replaces 6N0-W0078-A0-00 and 6G1-W0078-A1-00 is backordered and will ship as soon as it is back in stock.
Product Details
This water pump impeller repair kit is designed for servicing the cooling systems of select Yamaha and Mariner 6 HP and 8 HP 2-stroke outboards. The kit provides replacement water-pump components for applicable engines from the model and year ranges listed below. Proper water-pump service helps maintain cooling-water flow and reduce the risk of overheating caused by worn or damaged pump components.
The kit is listed as a replacement for Yamaha part numbers 6N0-W0078-A0-00, 6G1-W0078-A1-00, 6G1-W0078-00-00, and 6G1-W0078-01-00. It is also cross-referenced with aftermarket reference Sierra 18-3460.
- For select Yamaha and Mariner 6–8 HP 2-stroke outboards.
- Includes an impeller and related water-pump service components.
- Installation requires removal and servicing of the lower unit.
- Verify the exact engine model, year, and existing part number before ordering.
Part Number Matrix
Use the following references to compare the listed OEM and aftermarket numbers for your application.
| 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
This kit is listed for select Yamaha 6 HP and 8 HP 2-stroke models, including the model and year combinations shown below. Earlier applications generally use the 6G1-series references, while later applications generally use 6N0-W0078-A0-00. Model codes, year codes, and pump configurations can vary, so confirm the engine identification and old-part number before installation.
| Brand | Model | Rated HP | Stroke | Years | Reference | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 6MLHV, 6MSHV | 6 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 6MLHW, 6MSHW | 6 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 6MLHX, 6MSHX | 6 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 6MLHY, 6MSHY | 6 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MLHV, 8MSHV | 8 | 2-Stroke | 1997 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MLHW, 8MSHW | 8 | 2-Stroke | 1998 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MLHX, 8MSHX | 8 | 2-Stroke | 1999 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MLHY, 8MSHY | 8 | 2-Stroke | 2000 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MSHZ | 8 | 2-Stroke | 2001 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MSHA | 8 | 2-Stroke | 2002 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MSHB | 8 | 2-Stroke | 2003 | 6N0-W0078-A0-00 | Verify model identification before ordering. |
| Yamaha | 8MSH, 8MSHC | 8 | 2-Stroke | 2004 | 6N0-W0078-A0-00 | Multiple year codes may apply. |
| Yamaha | 8MSH, 8MSHD | 8 | 2-Stroke | 2005 | 6N0-W0078-A0-00 | Multiple year codes may apply. |
| Yamaha | 8MSH | 8 | 2-Stroke | 2006–2008 | 6N0-W0078-A0-00 | Includes listed year-code combinations 0608. |
| Yamaha | 8MSH | 8 | 2-Stroke | 2007–2009 | 6N0-W0078-A0-00 | Includes listed year-code combinations 0709. |
| Yamaha | 6C, 6D, 6J | 6 | 2-Stroke | 1984–1996 | 6G1-W0078-A1-00 | Earlier Yamaha applications. |
| Yamaha | 8C, 8J, 8N | 8 | 2-Stroke | 1984–1996 | 6G1-W0078-A1-00 | Earlier Yamaha applications. |
| Mariner | 6C | 6 | 2-Stroke | 1984–1986 | See listed cross-references | Verify the original pump components and part number. |
| Mariner | 6D | 6 | 2-Stroke | 1984–1986 | See listed cross-references | Verify the original pump components and part number. |
| Mariner | 8C | 8 | 2-Stroke | 1984–1986 | See listed cross-references | Verify the original pump components and part number. |
Technical Specs
- Product Type
- Water pump impeller repair kit
- Application
- Select Yamaha and Mariner 6–8 HP 2-stroke outboards
- Installation
- Lower-unit service
- Fitting Type
- Direct-fit replacement for listed applications
- Impeller Material
- Neoprene
- Warranty
- 1 year against manufacturing defects under normal use
What’s in the Box
- 1 × Water pump gasket — 6G1-44315-A0-00
- 1 × Cartridge insert — 6G1-44322-00-00 / 6G1-44322-02-00
- 1 × Cartridge outer plate — 6G1-44323-00-00
- 1 × Water seal damper — 647-44366-00-00
- 1 × Water pump impeller — 6G1-44352-00-00
- 1 × Plate kit — 6G1-44328-00-00
- 4 × Bolts — 97080-06405-00
Installation Notes
- Disconnect the battery where applicable and place the outboard in neutral.
- Remove the fasteners securing the lower unit to the upper casing.
- Lower the gearcase carefully, paying attention to the shift-shaft linkage, driveshaft, and water tube.
- Remove the existing water-pump housing and related components.
- Clean the driveshaft and mounting surfaces, removing old gasket material and sealant.
- Install the new gasket, plates, cartridge components, damper, and impeller. Orient the impeller vanes correctly; turning the driveshaft clockwise during installation is commonly used to seat the vanes.
- Reinstall the water-pump housing and tighten the fasteners to the applicable manufacturer specification.
- Reattach the lower unit while aligning the shift shaft, water tube, and driveshaft.
- Run the engine only with an appropriate water supply, such as a test tank or flushing muffs, and confirm proper cooling-water flow before normal use.
Troubleshooting & FAQ
My Yamaha is a 1996 or 1997 model. Which reference should I use?
Applications around the 1996–1997 transition can overlap. Earlier models generally use the 6G1-series references, while later models generally use 6N0-W0078-A0-00. Confirm the complete engine model and compare the existing pump components before ordering.
What are common signs of a worn water-pump impeller?
Common signs include weak or missing tell-tale water flow, overheating, steam from the exhaust, or reduced performance. Impeller replacement intervals depend on operating conditions, use, and the manufacturer's maintenance recommendations; inspect the component regularly, especially after saltwater use or extended storage.
Will this fit my Mariner outboard?
The listed Mariner applications are 6C, 6D, and 8C models from 1984–1986. Confirm the exact model, year, original part number, and pump configuration before ordering because model names alone do not establish fitment.
What is the difference between the Yamaha references?
The 6G1-W0078-00-00, 6G1-W0078-01-00, and 6G1-W0078-A1-00 references are associated with the earlier listed applications. The 6N0-W0078-A0-00 reference is associated with the later listed applications. Use the compatibility table and verify the original part before installation.
Is this an OEM part?
No. This is an aftermarket replacement kit, not a Yamaha or Mariner OEM component. The OEM and aftermarket numbers shown are reference numbers for comparison only.
What should I verify before ordering?
Confirm the brand, horsepower, 2-stroke configuration, complete model code, year, and existing water-pump reference. Compare the old components with the product images and listed contents before placing the order.
What are the warranty and return terms?
The kit is covered by a 1-year warranty against manufacturing defects under normal use. Returns are accepted in accordance with the applicable store policy; unused products should be returned in their original condition.
Safety & Important Information
- Verify the complete engine model, year, stroke, and part number before ordering.
- Do not operate the outboard without an adequate water supply.
- Follow the applicable service manual for disassembly, torque values, sealing procedures, and shift-shaft adjustment.
- Professional installation is recommended if you are not experienced with lower-unit service.
- This is an aftermarket replacement kit and is not an OEM component.
About Sea Sierra
- Pro-Grade Standards — Marine replacement parts selected for dependable service in real-world operating conditions.
- Fast Global Fulfillment — Standard delivery is available to most regions, with shipping options shown at checkout.
- Manufacturer-Direct Value — Competitive pricing with attention to materials and quality control.
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