Water Pump Impeller Repair Kit – Fits Yamaha 4-5HP (Replaces 6F5-W0078-00, 6F5-W0078-A0-00)
Water Pump Impeller Repair Kit – Fits Yamaha 4-5HP (Replaces 6F5-W0078-00, 6F5-W0078-A0-00) 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 Repair Kit – Fits Yamaha 4-5HP (Replaces 6F5-W0...
Water Pump Impeller Repair Kit – Fits Yamaha 4-5HP (Replaces 6F5-W0078-00, 6F5-W0078-A0-00) is backordered and will ship as soon as it is back in stock.
Product Details
This is an aftermarket Water Pump Impeller Repair Kit for Yamaha 4-5HP 2-Stroke (1984–2002) and 4HP F4 4-Stroke (1999–2008) outboard motors. It's engineered to restore your engine's cooling system to its original performance, preventing overheating and ensuring reliability on the water.
This kit is a direct replacement for Yamaha OEM part numbers 6F5-W0078-00-00, 6F5-W0078-A0-00, and 6E0-W0078-A2-00, providing a complete solution for maintenance or repair.
- Installs as a direct OEM-equivalent replacement.
- The neoprene rubber impeller is designed for durability and efficient water flow.
- Includes all necessary gaskets, seals, plates, and hardware for a full service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6F5-W0078-00-00 |
| Yamaha | 6F5-W0078-A0-00 |
| Yamaha | 6E0-W0078-A2-00 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mariner engines, this kit is only compatible with models having serial numbers starting with 6E0 or 6E3.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 4A | 4 | 2-Stroke | 1984–1999 | 6F5-W0078-00/6F5-W0078-A0-00 | |
| Yamaha | 5C | 5 | 2-Stroke | 1984–2002 | 6F5-W0078-00/6F5-W0078-A0-00 | |
| Yamaha | F4 | 4 | 4-Stroke | 1999–2001 | 6F5-W0078-00/6F5-W0078-A0-00 | |
| Yamaha | F4 | 4 | 4-Stroke | 2002–2008 | 6F5-W0078-00/6F5-W0078-A0-00 | |
| Mariner | 4A (6E0) | 4 | 2-Stroke | All | 6F5-W0078-00/6F5-W0078-A0-00 | Only with Serial Number 6E0 |
| Mariner | 5C (6E3) | 5 | 2-Stroke | All | 6F5-W0078-00/6F5-W0078-A0-00 | Only with Serial Number 6E3 |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct OEM Replacement
- Impeller Material
- Neoprene Rubber
What’s in the Box
- 1 x Water Seal Damper 2 (663-44366-00-00)
- 1 x Cartridge Insert (676-44322-00-00)
- 1 x Impeller (6F5-44352-00-00)
- 1 x Water Pump Gasket (676-44315-A1-00)
- 1 x Cartridge Outer Plate (676-44323-00-00)
- 1 x Cartridge Gasket (676-44324-A1-00)
- 1 x Water Pump Gasket (679-44316-A0-00)
- 2 x Bolts (97095-08055-00)
- 2 x Bolts (97095-08045-00)
- 4 x Washers (92990-08600-00)
- 1 x Woodruff Key (90280-04M00-00)
Installation Notes
- Disconnect the battery and shift the outboard into neutral. Remove the lower unit (gearcase) from the engine.
- Locate and unbolt the water pump housing, then carefully lift it off the driveshaft.
- Remove the old impeller, woodruff key, wear plate, gaskets, and seals. Take note of their orientation.
- Thoroughly clean all mating surfaces of the pump housing and base to remove old gasket material and corrosion.
- Install the new water seal damper and cartridge insert into the housing.
- Place the new woodruff key on the flat spot on the driveshaft.
- Apply a light coat of marine grease or a soap/water solution to the new impeller and install it onto the driveshaft, twisting in a clockwise direction to bend the vanes correctly.
- Fit the new gaskets and outer plate into place.
- Slide the water pump housing down over the impeller and driveshaft, ensuring a snug fit. Secure it with the provided bolts, tightening them to the manufacturer's specified torque.
- Reinstall the lower unit, reconnect the battery, and test the engine in water to confirm a strong, steady stream from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump impeller needs replacing?
Common signs of a failing impeller include a weak or intermittent water stream from the tell-tale outlet, engine overheating alarms, or a noticeable reduction in water pressure. For preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1-2 years or 100-200 operating hours.
Will this kit fit an engine model not listed in the compatibility table?
No. To avoid leaks, poor performance, or serious engine damage, you must only purchase this kit if your exact engine model and year range are listed in the compatibility section. Cross-referencing by the OEM part number is also a reliable method.
Is it necessary to replace all parts included in the kit?
Yes. For a comprehensive and reliable repair, it is crucial to replace all included seals, gaskets, O-rings, and the impeller as a complete set. Reusing old components can lead to premature failure and leaks.
Can I install just the impeller and reuse my old gaskets?
This is strongly discouraged. Gaskets and seals compress and harden over time and will not provide a reliable seal if reused. Always use all new components provided in the kit to ensure the pump is sealed correctly.
What is the recommended replacement interval for this water pump kit?
For optimal reliability and to prevent overheating, inspect your impeller annually. It is best to replace the full kit every 1-2 years or every 100-200 operating hours, especially if operating in saltwater or silty/sandy conditions.
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.
Payment & Security
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