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Water Pump Impeller Repair Kit – Fits Yamaha F40/F70 4-Stroke (Replaces 6CJ-W0078-00/6CJ-W0078-01-00)

Regular price $75.50

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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.

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller Repair Kit is engineered for Yamaha F40 and F70 4-Stroke outboard engines manufactured between 2011 and 2016 (models 6CY1-6CY7 and 6CJ1-6CJ7). It provides all necessary components to restore your engine’s cooling system to factory-level performance, ensuring optimal reliability and preventing overheating issues.

It serves as a direct replacement for Yamaha part numbers 6CJ-W0078-00-00 and 6CJ-W0078-01-00, and interchanges with Quicksilver 8M6012800 and Sierra 18-3494.

  • Designed for direct OEM replacement, ensuring a precise fit.
  • Constructed with a premium rubber impeller and stainless steel hardware for durability in marine environments.
  • Manufactured in an ISO9002 certified facility to meet or exceed original equipment specifications.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand Part Number
Yamaha 6CJ-W0078-00-00
Yamaha 6CJ-W0078-01-00
Quicksilver 8M6012800
Sierra 18-3494

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Yamaha owners, this kit is specifically designed for F40 models designated 6CY1 through 6CY7 and F70 models designated 6CJ1 through 6CJ7.

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 2011–2016 6CJ-W0078-00-00/6CJ-W0078-01-00 Models 6CJ1 to 6CJ7

Technical Specs

Product Type
Water Pump Impeller Repair Kit
Installation
Direct OEM replacement
Material
Premium rubber (impeller), Stainless steel (hardware)
Compatibility
F40 and F70 Yamaha 4-stroke outboards
Manufacturing Standards
ISO9002 certified factory
Other Technical Attributes
Manufactured to OEM specifications

What’s in the Box

  • 1 x Water Pump Impeller (6CJ-W0078-00-00)
  • 1 x Housing Cover
  • 1 x Impeller Key
  • 1 x O-ring
  • 1 x Oil Seal
  • 1 x Wear Plate
  • 1 x Water Seal Damper
  • 1 x Set of Water Pump Gaskets
  • 1 x Pin
  • 1 x Set of Bolts and Washers

Installation Notes

  1. Disconnect the negative battery cable before starting work.
  2. Remove the lower unit (gearcase) from the outboard engine. You may need to disconnect the speedometer tube.
  3. Unbolt and remove the water pump housing to access the old impeller.
  4. Slide the old impeller off the driveshaft, removing the impeller key. Note the direction of the old vanes.
  5. Clean the housing interior and wear plate of any debris or corrosion. Replace the plate and gaskets.
  6. Install the new impeller key and slide the new impeller onto the driveshaft, rotating it in a clockwise direction to bend the vanes correctly.
  7. Reinstall the housing, applying a non-permanent sealant to the bolts if required.
  8. Re-attach the lower unit to the engine, ensuring all connections are secure. Once assembled, test the engine in water to confirm a strong water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I know if this kit fits my Yamaha engine?

This kit is specifically for Yamaha F40 and F70 4-Stroke outboards from 2011–2016. Please check your engine's model code; it fits F40 models 6CY1 to 6CY7 and F70 models 6CJ1 to 6CJ7. If your model or year is different, do not purchase.

What are the signs of a failing water pump impeller?

Common symptoms include a weak or inconsistent water stream from the "tell-tale" outlet, the engine overheating alarm sounding, or steam coming from the exhaust. Reduced cooling efficiency can cause severe engine damage if not addressed.

How often should I replace the water pump impeller?

For preventative maintenance, it is recommended to replace the impeller every 1 to 2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).

Why is this kit a better choice than buying just an impeller?

This is a complete kit that includes the housing, wear plate, gaskets, and seals. These peripheral parts wear out over time and can cause leaks or reduce pump efficiency even with a new impeller. Replacing all components at once ensures a reliable, long-lasting repair.

What is the difference between part number 6CJ-W0078-00-00 and 6CJ-W0078-01-00?

The part number 6CJ-W0078-01-00 is a supersession, meaning it is a newer revision that has replaced the older 6CJ-W0078-00-00 part number. They are functionally identical and fully interchangeable. Our kit is a direct replacement for both.

Can I install this water pump kit myself?

Yes, installation is possible for those with mechanical experience and the correct tools. However, due to the critical nature of the engine's cooling system, professional installation is always recommended to ensure safety and correct function.

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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