Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00, 18-3410)
Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00, 18-3410) is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-...
Water Pump Impeller Kit – Fits Yamaha 4HP/5HP 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00, 18-3410) 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 2-Stroke, F4/F5/F6 4-Stroke (Replaces 6E0-W0078-A2-00) provides all necessary components for a full water pump service. It is designed for Yamaha 2-Stroke 4HP and 5HP models (1988–2019) and 4-Stroke F4, F5, and F6 single-cylinder outboards (1998–2011), ensuring reliable engine cooling and performance.
This kit serves as a direct replacement for Yamaha OEM part numbers 6E0-W0078-A2-00, 6E0-W0078-00-00, 6E0-W0078-01-00, 6E0-W0078-02-00, and 6E0-W0078-A3-00, as well as Sierra 18-3410 and AM6E0-W0078-A2.
- Engineered for direct-fit installation, matching OEM specifications.
- Includes a high-quality rubber impeller and durable housing components.
- Complete kit contains all essential seals, gaskets, and hardware for a full service.
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 |
| Sierra | 18-3410 |
| Generic Aftermarket | AM6E0-W0078-A2 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is designed specifically for the listed Yamaha outboard models. Please verify your engine's model and year range before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 4A, 4AC, 4ACMH, 4CMH | 4 | 2-Stroke | 1988–2019 | 6E0-W0078-A2-00 | |
| Yamaha | 5C, 5CM, 5CMH | 5 | 2-Stroke | 1988–2015 | 6E0-W0078-A2-00 | |
| Yamaha | F4 | 4 | 4-Stroke | 1998–2011 | 6E0-W0078-A2-00 | 1-cylinder models |
| Yamaha | F5 | 5 | 4-Stroke | 1998–2011 | 6E0-W0078-A2-00 | 1-cylinder models |
| Yamaha | F6 | 6 | 4-Stroke | 1998–2011 | 6E0-W0078-A2-00 | 1-cylinder models |
Technical Specs
- Product Type
- Water Pump Impeller Repair Kit
- Installation
- Direct replacement
- Housing Material
- Rubber (impeller), Aluminum/Alloy (components)
- Housing Color
- Black (impeller), Silver (metal parts)
- Fitting Type
- Direct fit
- Other Technical Attributes
- Complete service kit for water pump impeller replacement
What’s in the Box
- 1 x Impeller (6E0-44352-00)
- 1 x Water Pump Housing Insert Cup
- 1 x Impeller Plate
- 1 x Gasket
- 1 x Impeller Key
- Mounting Hardware (bolts/screws)
Installation Notes
- Disconnect the battery and remove the engine cover.
- Shift the engine into neutral gear.
- Remove the bolts securing the lower unit (gearcase) to the upper casing.
- Carefully lower the gearcase to expose the driveshaft and water pump housing.
- Unbolt and remove the water pump housing cover to access the impeller.
- Remove the old impeller, gasket, wear plate, and insert cup. Note the orientation of the impeller vanes.
- Clean all surfaces thoroughly, removing any old gasket material or debris.
- Install the new components from the kit in reverse order. Lightly grease the new impeller.
- Ensure the impeller key is correctly seated and rotate the driveshaft clockwise while sliding the housing down to bend the vanes correctly.
- Re-install the water pump housing, lower unit, and all bolts to the manufacturer's torque specifications.
Troubleshooting & FAQ
How do I know if this kit fits my Yamaha engine?
This kit is specifically for Yamaha 4HP/5HP 2-stroke (1988–2019) and F4/F5/F6 4-stroke 1-cylinder models (1998–2011). Please cross-reference your engine model and year with the compatibility table provided. Also, check that your existing part number matches one of the equivalents listed in our Part Number Matrix.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent "telltale" water stream, or a brittle/cracked/melted impeller upon inspection. Reduced cooling performance can cause severe engine damage.
How often should I replace my water pump impeller?
For preventative maintenance, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use, whichever comes first. This interval can be shorter if you frequently operate in sandy, silty, or saltwater conditions.
Can I just replace the impeller and not the whole kit?
While possible, it is highly recommended to replace all components in the kit—including the housing cup, plate, gaskets, and seals. These parts wear together, and replacing only the impeller can lead to a poor seal and premature failure of the new part.
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 T& 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
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
