Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00, 18-3479)
Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00, 18-3479) 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 15/20 HP 4-Stroke (Replaces 6...
Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00, 18-3479) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Impeller Kit provides all necessary components for a complete service of Yamaha 15 HP (F15, F15C) and 20 HP (F20, F20A) 4-stroke outboard motors from 2006 to 2022. It ensures your engine’s cooling system operates efficiently.
The kit is a direct replacement for Yamaha part numbers 6AH-W0078-00-00, 6AH-W0078-01-00, and 6AH-W0078-02-00. It also serves as an interchange for Sierra Marine 18-3479 and is equivalent to 68T-W0078-00-00.
- Engineered for a direct OEM-replacement fit and function.
- Includes a full set of wear items including the housing, impeller, plates, and gaskets.
- Manufactured in an ISO9002 certified facility to meet strict quality control standards.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Yamaha | 6AH-W0078-00-00 |
| Yamaha | 6AH-W0078-01-00 |
| Yamaha | 6AH-W0078-02-00 |
| Yamaha | 68T-W0078-00-00 |
| Sierra Marine | 18-3479 |
Engine & Model Compatibility
Confirm your engine model and year in the tables below to ensure proper fitment.
Yamaha: This kit is designed for a range of Yamaha 4-stroke models from 9.9 HP to 20 HP. Please verify your specific model and year below. Note: It does not fit F15B or F20B models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F15C | 15 | 4-Stroke | 2006 and newer | 6AH-W0078-00-00 | |
| Yamaha | F15 (6AG1 TO 6AG9) | 15 | 4-Stroke | 2007–2014 | 6AH-W0078-00-00 | |
| Yamaha | F15 (6AGA TO 6AGB) | 15 | 4-Stroke | 2015–2016 | 6AH-W0078-00-00 | |
| Yamaha | F20A | 20 | 4-Stroke | 2006 and newer | 6AH-W0078-00-00 | |
| Yamaha | F20 (6AH1 TO 6AH9) | 20 | 4-Stroke | 2007–2014 | 6AH-W0078-00-00 | |
| Yamaha | F20 (6AHA TO 6AHB) | 20 | 4-Stroke | 2015–2016 | 6AH-W0078-00-00 | |
| Yamaha | F9.9 (6CA1-6AC9) | 9.9 | 4-Stroke | 2009–2016 | 6AH-W0078-00-00 | |
| Yamaha | F13.5 (6AF1 TO 6AF3) | 13.5 | 4-Stroke | 2007–2009 | 6AH-W0078-00-00 |
Parsun: Compatibility with Parsun engines is noted by aftermarket suppliers, but specific model years are not confirmed. Please verify fitment by comparing your existing part numbers before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Parsun | F15A | 15 | 4-Stroke | |||
| Parsun | F20A | 20 | 4-Stroke | |||
| Parsun | F15 EFI | 15 | 4-Stroke | |||
| Parsun | F20 EFI | 20 | 4-Stroke |
Technical Specs
- Product Type
- Water Pump Impeller Service Kit
- Installation
- Direct OEM replacement
- Other Technical Attributes
- Manufactured to OEM specifications, produced in ISO9002 certified factory
What’s in the Box
- 1 x Water Pump Housing (6AH-44311-00-00)
- 1 x Insert, Cartridge (63V-44322-00-00)
- 1 x Damper, Water Seal (6L2-44367-00-00)
- 1 x Water Pump Impeller (63V-44352-01-00)
- 1 x Impeller Key, Woodruff (664-44338-00-00)
- 1 x O-Ring (93210-49046-00)
- 1 x Outer Plate, Cartridge (6AH-44323-00-00/68T-44323-00-00)
- 2 x Plate (63V-44328-01-00)
- 2 x Pin, Dowel (93604-10M03-00/93604-12M07-00)
- 4 x Bolt (97095-08045-00)
Installation Notes
- Disconnect the battery and shift the outboard into the neutral position.
- Remove the bolts securing the lower unit (gearcase) and carefully separate it from the engine's upper section.
- Unbolt and remove the old water pump housing, taking note of the orientation of all parts as you disassemble.
- Remove the old impeller, woodruff key, wear plates, and gaskets.
- Thoroughly clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new components from the kit in the reverse order of removal. Lightly lubricate the new impeller and housing interior with marine grease.
- Ensure the impeller key is properly seated before sliding the impeller into place.
- Reinstall the water pump housing and tighten the bolts to the manufacturer's specified torque.
- Carefully guide the lower unit back into position, ensuring the driveshaft, shift shaft, and water tube are correctly aligned. Secure with bolts.
- Reconnect the battery, start the engine in water, and confirm a steady water stream from the tell-tale port.
Troubleshooting & FAQ
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating at idle or low speeds, a weak or intermittent water stream from the "tell-tale" outlet, or an alarm from the engine's temperature sensor. Upon inspection, you may find the impeller blades are cracked, brittle, or have taken a permanent "set".
How often should I replace my water pump impeller kit?
For preventative maintenance, it is recommended to inspect the impeller annually and replace the entire water pump kit every 2-3 years or 200-300 hours of operation, whichever comes first. This interval may be shorter if you operate frequently in sandy, silty, or saltwater conditions.
Will this kit fit a Yamaha F20B model?
No. This kit is specifically designed for the F15/F15C and F20/F20A models. It is not compatible with Yamaha F15B or F20B models, which use a different water pump assembly.
What is the difference between 6AH-W0078-00, 6AH-W0078-01, and 6AH-W0078-02?
These are official Yamaha part number supersessions. The -01-00 and -02-00 are newer, revised versions of the original -00-00 kit. All are functionally identical and fully interchangeable. Our kit is a replacement for all of these versions.
Can I just replace the impeller instead of the whole kit?
While technically possible, it is strongly recommended to replace the entire kit. The housing, wear plates, and seals wear down along with the impeller. Installing a new impeller into a worn housing can lead to poor performance and premature failure.
Is this an OEM or aftermarket part?
This listing is for a high-quality aftermarket replacement part, not an OEM component. It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 certified facility, with batch inspections to ensure consistency and performance.
How fast do you ship and what are the costs?
We ship worldwide quickly, with typical transit times of 5–15 days for most regions. Standard shipping is free on all orders. Expedited shipping options, where available, will be presented at checkout for an additional fee.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use conditions. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchasing. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component. Brand names and part numbers are used for reference purposes only.
- Professional installation is highly recommended for safety and to ensure proper performance. Incorrect installation can lead to engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world performance and durability.
- Fast Global Fulfillment — With warehouses strategically located, we offer free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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