Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00, 6CJ-W0078-01)
Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00, 6CJ-W0078-01) is backordered and will ship as soon as it is back in stock.
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Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6C...
Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00, 6CJ-W0078-01) is backordered and will ship as soon as it is back in stock.
Product Details
This complete Water Pump Impeller Kit – Fits Yamaha F40/F70 4-Stroke 2010–2016 (Replaces 6CJ-W0078-00, 6CJ-W0078-01) provides all necessary components to service the water pump assembly in compatible Yamaha outboard lower units. It is designed for specific Yamaha F40 (6CY) and F70 (6CJ) 4-Stroke models manufactured between 2010 and 2016.
This kit is a direct replacement for Yamaha OEM part numbers 6CJ-W0078-00-00 and 6CJ-W0078-01-00, as well as Sierra 18-3494, JLM Marine AM6CJ-W0078-00, and Forestity 6CJ-W0078-00.
- Installs in the lower unit (gearcase) to restore cooling system performance.
- Includes a new impeller, gaskets, seals, and housing cover for a complete rebuild.
- Offers a choice between genuine OEM and high-quality aftermarket options.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By |
|---|---|---|
| Yamaha | 6CJ-W0078-00-00 | 6CJ-W0078-01-00 |
| Yamaha | 6CJ-W0078-01-00 | |
| Sierra | 18-3494 | |
| JLM Marine | AM6CJ-W0078-00 | |
| Forestity | 6CJ-W0078-00 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is specifically designed for Yamaha outboards. Please verify your model code (e.g., F70LA) and year range to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F40 | 40 | 4-Stroke | 2011–2016 | 6CJ-W0078-00-00, 6CJ-W0078-01-00 | Models 6CY1 to 6CY7 |
| Yamaha | F70 | 70 | 4-Stroke | 2010–2016 | 6CJ-W0078-00-00, 6CJ-W0078-01-00 | Models 6CJ1 to 6CJ7 |
| Yamaha | F70LA | 70 | 4-Stroke | 2010–2021 | 6CJ-W0078-00-00, 6CJ-W0078-01-00 | Also F70LA2 models |
Technical Specs
- Product Type
- Water Pump Impeller Service Kit
- Installation
- Lower Unit / Gearcase
- Connection
- Direct Drive
- Other Technical Attributes
- Genuine OEM and high-quality aftermarket options available
What’s in the Box
- 1 x Insert, Cartridge (63D-44322-00-00)
- 1 x Gasket, Water Pump (6CJ-44315-00-00)
- 1 x Cover, Pump Housing (63D-44312-00-00)
- 1 x Damper, Water Seal (663-44366-00-00 / 663-44366-01-00)
- 1 x Impeller (6H3-44352-00-00)
- 1 x Key, Woodruff (90280-03M03-00)
- 2 x Oil Seal (93101-23070-00)
- 1 x O-Ring (93210-46044-00)
- 1 x Gasket, Water Pump (6CJ-44316-00-00)
- 1 x Outer Plate, Cartridge (6CJ-44323-00-00)
- 1 x Gasket, Cartridge (6CJ-44324-00-00)
- 2 x Pin, Dowel (93604-10M03-00)
- 2 x Bolt, With Washer (90119-08M33-00)
- 2 x Bolt, With Washer (90119-08M14-00)
Installation Notes
- Disconnect the battery and place the outboard motor in the neutral gear position.
- Remove the lower unit (gearcase) from the outboard by unfastening the mounting bolts.
- Position the lower unit securely on a workbench. Remove the bolts securing the water pump housing.
- Carefully lift the water pump housing, taking note of the position of all parts. Remove the old impeller, gaskets, seals, and wear plate.
- Clean all mating surfaces thoroughly, removing any old gasket material or corrosion.
- Install the new components from the kit in the reverse order of disassembly. Lightly grease the new impeller and insert it while turning the driveshaft clockwise.
- Ensure the Woodruff key is correctly seated and the impeller is properly engaged.
- Reinstall the water pump housing and torque its bolts to the manufacturer's specifications.
- Reattach the lower unit to the outboard motor.
- Once fully assembled, start the engine in water and verify a steady stream of water is exiting the tell-tale outlet.
Troubleshooting & FAQ
Which Yamaha engines does this kit fit?
This kit is confirmed to fit Yamaha 4-Stroke models F40 (2011–2016), F70 (2010–2016), and F70LA (2010–2021). Always check the specific model codes and notes in the compatibility table to ensure a perfect match.
What is the difference between part 6CJ-W0078-00-00 and 6CJ-W0078-01-00?
Part number 6CJ-W0078-01-00 is a direct supersession for 6CJ-W0078-00-00. This means it is the updated version from Yamaha, and the kits are interchangeable. Our kit replaces both versions.
How often should the water pump impeller be replaced?
As a general maintenance rule, the impeller should be inspected annually and replaced every 2-3 years or every 200-300 hours of use, whichever comes first. This interval can be shorter if the engine is operated in saltwater or sandy/silty conditions.
What are the signs of a failing water pump impeller?
Common symptoms include a weak or non-existent water stream from the tell-tale outlet, engine overheating alarms, and reduced engine performance. If you notice any of these signs, inspect the cooling system immediately.
Does this kit include the water pump housing?
This is a complete service kit that includes the essential wear items. It contains the Cover, Pump Housing (63D-44312-00-00) and Cartridge Insert (63D-44322-00-00), but not the entire lower pump housing assembly.
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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