Water Pump Impeller Kit – Fits Yamaha 4-5HP (Replaces 6E0-W0078-A2-00)
Water Pump Impeller Kit – Fits Yamaha 4-5HP (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
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Water Pump Impeller Kit – Fits Yamaha 4-5HP (Replaces 6E0-W0078-A2-00)
Water Pump Impeller Kit – Fits Yamaha 4-5HP (Replaces 6E0-W0078-A2-00) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Water Pump Impeller Kit provides all the necessary components for a complete service of the water pump on select Yamaha and Mariner outboards. It is engineered for a precise fit on Yamaha 2-Stroke 4HP (1984–1999) & 5HP (1984–2002) and 4-Stroke F4 (1999–2008) models, ensuring reliable cooling performance.
The kit serves as a direct cross-reference for Yamaha OEM part numbers 6E0-W0078-A2-00, 6E0-W0078-A3-00, 6E0-W0078-02-00, and several other equivalents, making it a versatile solution for maintenance and repairs.
- Designed for direct replacement of the factory water pump assembly.
- Includes all essential gaskets, plates, and hardware required for a full rebuild.
- Built with quality materials that meet or exceed OEM specifications for durability in marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6E0-W0078-A2-00 | Primary Replacement |
| Yamaha | 6E0-W0078-A3-00 | Interchangeable |
| Yamaha | 6E0-W0078-02-00 | Interchangeable |
| Yamaha | 6E0-W0078-01-00 | Interchangeable |
| Yamaha | 6E0-W0078-00-00 | Interchangeable |
| Aftermarket | AM6E0-W0078-A2 | |
| Aftermarket | HJ YHJB-6E0 |
Engine & Model Compatibility
Confirm your engine model and year in the tables below. Proper fitment is critical.
For Yamaha applications, this kit covers specific 4HP and 5HP models across 2-stroke and 4-stroke platforms from 1984 to 2008.
For Mariner outboards, this kit fits specific 4HP and 5HP models designated with serial numbers starting in 6E0 or 6E3. Please verify your engine's serial number before ordering.
| 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 | 4MLHU, 4MLHU2, 4MSHU, 4MSHU2 | 4 | 2-Stroke | 1996 | 6E0-W0078-A2-00 | |
| Yamaha | 5C, 5CM, 5CMH | 5 | 2-Stroke | 1984–2002 | 6E0-W0078-A2-00 | |
| Yamaha | 5MLHU, 5MLHU2, 5MSHU, 5MSHU2 | 5 | 2-Stroke | 1996 | 6E0-W0078-A2-00 | |
| Yamaha | F4 | 4 | 4-Stroke | 1999–2008 | 6E0-W0078-A2-00 | |
| Mariner | 4A(6E0) | 4 | 2-Stroke | 6E0-W0078-A2-00 | Models with Serial Number 6E0 | |
| Mariner | 5C(6E3) | 5 | 2-Stroke | 6E0-W0078-A2-00 | Models with Serial Number 6E3 | |
| Mariner | 96325T, 96325M | 4, 5 | 2-Stroke | 6E0-W0078-A2-00 | Only with Serial Number 6E0 & 6E3 |
Technical Specs
- Product Type
- Water Pump Impeller Kit
- Installation
- Direct replacement
- Other Technical Attributes
- High-quality materials designed to OEM specifications
What’s in the Box
- 1 x Water Pump Housing (6E0-44311-00-00)
- 1 x Water Pump Gasket (6E0-44315-A0-00)
- 1 x Cartridge Insert (6E0-44322-02-00)
- 1 x Cartridge Outer Plate (6E0-44323-00-00)
- 1 x Impeller (6E0-44352-00-00)
- 1 x Water Seal Damper 2 (6E0-44366-00-00)
- 1 x Dowel Pin (93604-09066-00)
- 4 x Bolt (97080-06045-00/97095-06045-00)
Installation Notes
- Before starting, disconnect the negative battery cable for safety.
- Position a drain pan and carefully remove the lower unit (gearcase) from the outboard's midsection.
- Locate the water pump housing on top of the gearcase and remove its mounting bolts.
- Lift off the housing and remove the old impeller, wear plate, and any gaskets. Note the orientation of the impeller vanes.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new gasket, wear plate, and cartridge insert from the kit.
- Slide the new impeller onto the driveshaft, ensuring the key or keyway is properly aligned. Turn the driveshaft clockwise to seat the vanes correctly inside the new housing.
- Apply a light coat of marine grease to the inside of the housing and on the impeller.
- Secure the new housing with the provided bolts, tightening them to the manufacturer's specified torque in a crisscross pattern.
- Reinstall the lower unit, ensuring the driveshaft and shift shaft align correctly.
- Once assembled, test the engine in a water-filled barrel or with a flush attachment to confirm a strong, steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How can I confirm this kit will fit my specific motor?
The most reliable method is to check your motor's model and serial number against the Engine & Model Compatibility table on this page. For Mariner applications, verifying the serial number prefix (e.g., 6E0, 6E3) is essential as year ranges can be unclear.
What are common symptoms of a worn or failed impeller?
The most common signs include a weak or non-existent water stream from the "tell-tale" outlet, an engine overheating alarm, or a noticeable reduction in engine performance. A damaged impeller cannot pump enough water to cool the engine effectively.
How often should a water pump impeller be replaced?
As a preventative maintenance item, it is recommended to replace the impeller and gaskets every 1 to 2 years, or every 100-200 hours of operation, whichever comes first. This interval may be shorter if you frequently operate in sandy, silty, or saltwater conditions.
My old bolts have a slightly different part number. Can I use the bolts in this kit?
Yes. This kit includes bolts that cover common variations like 97080-06045-00 and 97095-06045-00. These are typically interchangeable for this specific water pump application, and our kits are confirmed to fit the models listed.
Is any special grease required for installation?
Yes, it is highly recommended to apply a light coat of a water-resistant marine grease (like lithium or silicone-based) to the inside of the pump housing and to the new impeller. This lubricates the impeller on its first dry start and helps it seat correctly.
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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