Water Pump Impeller Kit – Fits Yamaha 4HP-5HP (Replaces 6E0-W0078-A2-00)
Water Pump Impeller Kit – Fits Yamaha 4HP-5HP (Replaces 6E0-W0078-A2-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
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Water Pump Impeller Kit – Fits Yamaha 4HP-5HP (Replaces 6E0-W0078-A...
Water Pump Impeller Kit – Fits Yamaha 4HP-5HP (Replaces 6E0-W0078-A2-00) is backordered and will ship as soon as it is back in stock.
Product Details
This complete Water Pump Impeller Kit – Fits Yamaha 4HP & 5HP Outboards (Replaces 6E0-W0078-A2-00) provides everything needed for a full water pump service. It is designed for Yamaha 2-stroke 4HP (1984–1999) and 5HP (1984–2002) models, 4-stroke F4 (1999–2008) models, and specific 1996 Mariner 4HP and 5HP outboards with 6E0 and 6E3 series serial numbers.
The kit serves as a direct interchange for Yamaha part numbers 6E0-W0078-A2-00, 6E0-W0078-00-00, 6E0-W0078-01-00, 6E0-W0078-02-00, and several others, ensuring broad compatibility.
- Installs as a direct replacement for the original OEM assembly.
- Features a durable, marine-grade aluminum housing for corrosion resistance.
- Includes all necessary gaskets, seals, and hardware for a complete installation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6E0-W0078-A2-00 |
| Yamaha | 6E0-W0078-00-00 |
| Yamaha | 6E0-W0078-01-00 |
| Yamaha | 6E0-W0078-02-00 |
| Yamaha | 6E0-W0078-A3-00 |
| Yamaha | 6E0-W0078-A4-00 |
| Yamaha | 6E0-W0078-A5-00 |
| Yamaha | 68D-WG078-00-00 |
| Yamaha | 67D-W0078-00-00 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha owners, this kit fits various 4A, 4AC, 5C, and F4 series models produced between 1984 and 2008. Verify your specific model and year range.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 4A, 4AC, 4ACMH, 4CMH | 4 | 2-Stroke | 1984–1999 | 6E0-W0078-A2-00 | |
| Yamaha | 5C, 5CM, 5CMH | 5 | 2-Stroke | 1984–2002 | 6E0-W0078-A2-00 | |
| Yamaha | F4 | 4 | 4-Stroke | 1999–2008 | 6E0-W0078-A2-00 |
For Mariner owners, eligibility is strictly limited to 1996 models with specific serial number prefixes. Please inspect your engine's identification plate before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mariner | 4HP (with serial 6E0) | 4 | 2-Stroke | 1996 | 6E0-W0078-A2-00 | Only for models with 6E0 & 6E3 serial numbers |
| Mariner | 5HP (with serial 6E3) | 5 | 2-Stroke | 1996 | 6E0-W0078-A2-00 | Only for models with 6E0 & 6E3 serial numbers |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct replacement
- Housing Material
- Aluminum (marine-grade)
What’s in the Box
- 1 x Housing, Water Pump (6E0-44311-00-00)
- 1 x Gasket, Water Pump (6E0-44315-A0-00)
- 1 x Insert, Cartridge (6E0-44322-02-00)
- 1 x Outer Plate, Cartridge (6E0-44323-00-00)
- 1 x Impeller (6E0-44352-00-00)
- 1 x Damper, Water Seal (6E0-44366-00-00)
- 1 x Pin, Dowel (93604-09066-00)
- 4 x Bolt (97080-06045-00)
Installation Notes
- Disconnect the spark plug wire(s) and battery cables for safety.
- Place a drain pan under the lower unit and remove the gear oil drain screw to empty the gearcase.
- Remove the bolts securing the lower unit (gearcase) to the upper driveshaft housing. Carefully separate the lower unit.
- Unbolt and remove the old water pump housing. Note the orientation of the old impeller vanes.
- Remove the old impeller, gaskets, wear plate, and any seals. Clean all mating surfaces thoroughly.
- Install the new gasket, wear plate, and dowel pins from the kit.
- Slide the new impeller onto the driveshaft, turning the shaft clockwise to seat the vanes correctly inside the new housing.
- Install the new housing and torque the bolts to the manufacturer's specification.
- Re-install the lower unit, ensuring the driveshaft, shift shaft, and water tube align correctly.
- Refill the lower unit with the specified marine gear lubricant.
- Reconnect the battery and spark plug wires. Test the engine in water, confirming a strong stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump needs replacing?
Common signs of a failing water pump include a weak or non-existent water stream from the tell-tale outlet, engine overheating alarms, or discovering a brittle, cracked, or deformed impeller during a routine inspection.
Will this kit fit my specific Mariner outboard?
This kit is only confirmed to fit 1996 Mariner 4HP and 5HP models that have a serial number containing "6E0" or "6E3". It is critical to check your engine's identification plate before purchasing as it will not fit other Mariner models or years.
What is the recommended replacement interval for this kit?
For optimal reliability and to prevent engine damage from overheating, we recommend inspecting the impeller annually and replacing the entire water pump kit every 2-3 years or 200-300 running hours, whichever comes first. Usage in saltwater or silty/sandy conditions may require more frequent service.
Does this kit include the outer housing?
Yes, this is a complete repair kit that includes the main water pump housing (replaces 6E0-44311-00-00) along with the impeller, gaskets, cartridge insert, outer plate, and all required installation hardware.
What is the difference between an OEM and an aftermarket part?
This listing is an aftermarket replacement, not a component from the original engine manufacturer (OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 certified facility, with batch-inspections to ensure quality and consistency.
What are the shipping speed and cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most regions. 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 use conditions. Should any issues arise, please contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. See our full policy page or reach out for return 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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