Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00)
Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00) 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 15/20 HP 4-Stroke (Replaces 6...
Water Pump Impeller Kit – Fits Yamaha 15/20 HP 4-Stroke (Replaces 6AH-W0078-00-00) 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 on select Yamaha 15 HP and 20 HP 4-stroke outboard motors manufactured from 2006 onwards. It is engineered to restore the cooling system's performance and reliability, preventing engine damage from overheating.
This kit is a direct aftermarket replacement for Yamaha part numbers 6AH-W0078-00-00, 6AH-W0078-01-00, 6AH-W0078-02-00, 68T-W0078-00-00, and Sierra 18-3479.
- Installs as a direct OEM-equivalent replacement.
- Manufactured in an ISO9002 certified facility to meet or exceed OEM specifications.
- Includes all essential gaskets, seals, and hardware for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6AH-W0078-00-00 | Primary Part Number |
| Yamaha | 6AH-W0078-01-00 | Superseded Part |
| Yamaha | 6AH-W0078-02-00 | Superseded Part |
| Yamaha | 68T-W0078-00-00 | Equivalent Kit |
| Sierra | 18-3479 | Aftermarket Interchange |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure correct fitment.
This kit is designed for Yamaha 4-stroke models listed below. While it may fit certain Parsun models, we recommend verifying the specific part number with your engine's service manual before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| 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 |
Technical Specs
- Product Type
- Water Pump Impeller Service Kit
- Installation
- Direct OEM replacement
- Housing Material
- Cast Iron
- Manufacturing
- Manufactured to OEM specifications in an ISO9002 certified factory.
- Warranty
- 1 year against manufacturing defects (JLM Marine)
What’s in the Box
- 1 x Water Pump Housing (6AH-44311-00-00)
- 1 x Cartridge Insert (63V-44322-00-00)
- 1 x Water Seal Damper (6L2-44367-01-00)
- 1 x Water Pump Impeller (63V-44352-01-00)
- 1 x Woodruff Key (664-44338-00-00)
- 1 x O-Ring (93210-49046-00)
- 1 x Cartridge Outer Plate (6AH-44323-00-00)
- 2 x Plate (63V-44328-01-00)
- 2 x Dowel Pin (93604-10M03-00)
- 4 x Bolt (97095-08045-00)
Installation Notes
- Disconnect the negative battery cable and remove the engine cover.
- Remove the lower unit (gearcase) from the outboard motor.
- Unbolt and remove the existing water pump housing to access the impeller.
- Clean all mating surfaces, removing any old gasket material or corrosion.
- Install the new components from the kit, ensuring the impeller vanes are oriented correctly (typically spinning clockwise during installation).
- Reassemble the pump housing, torque bolts to manufacturer specifications, and reinstall the lower unit.
- Before starting the engine, use a flush attachment or submerge the lower unit in water to ensure the pump is primed and check for proper water flow from the tell-tale outlet.
Troubleshooting & FAQ
How do I confirm this kit fits my engine?
Check your engine's model, rated HP, and year against our compatibility chart. It is critical to also verify that the OEM part number for your motor (e.g., 6AH-W0078-00-00) is listed in the Part Number Matrix.
What are the signs of a failing water pump impeller?
Common symptoms include the engine overheating, a persistent alarm sounding, or a weak, inconsistent, or non-existent water stream from the "tell-tale" diagnostic outlet.
How often should an impeller be replaced?
For preventative maintenance, most manufacturers recommend replacing the impeller and associated wear components every 1 to 2 years or every 100-200 operating hours, whichever comes first. This interval may be shorter in saltwater or silty conditions.
Does this service kit include the housing?
Yes, this is a complete water pump impeller service kit that includes the main housing, impeller, wear plates, gaskets, o-rings, and installation hardware as detailed in the "What’s in the Box" section.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It's built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch-inspections for quality and consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most orders, and expedited options are available at checkout where applicable.
Warranty & returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is recommended for safety and optimal performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with an average transit time of 5–15 days.
- Manufacturer-Direct Value — Our parts are priced fairly by eliminating middlemen, without compromising on materials or quality control.
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