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Water Pump Impeller Repair Kit – Fits Yamaha 40-90HP Outboards (Replaces 63D-W0078-01-00, 63D-W0078-02-00, 63D-W0078-03-00)

Sale price $21.99 Regular price $95.00
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Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

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 – Fits Yamaha 40-90HP Outboards (Replaces 63D-W0078-01-00, 63D-W0078-02-00, 63D-W0078-03-00) is designed for a wide range of Yamaha 40–90HP 2-Stroke & 4-Stroke outboard motors manufactured from 1984 to the present. It is compatible with various F40, F50, F60, F70, F75, F80, F90 four-stroke and 40, 50, 60, 70, 75, 90 two-stroke models.

It serves as a direct aftermarket replacement for Yamaha OEM part numbers in the 63D-W0078-01-00, 63D-W0078-02-00, and 63D-W0078-03-00 supersession chain.

  • Installs in the lower unit (gear case) to restore the engine cooling system.
  • Engineered to prevent engine damage from overheating.
  • Complete kit includes the impeller, wear plate, gaskets, O-rings, and installation hardware.

Part Number Matrix

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

Brand Part Number Superseded By Notes
Yamaha 63D-W0078-01-00 63D-W0078-02-00 Initial part number.
Yamaha 63D-W0078-02-00 63D-W0078-03-00 Second version.
Yamaha 63D-W0078-03-00 - Current and final part number in the chain.

Engine & Model Compatibility

Confirm your engine model and year in the table below. This kit is known to fit the following Yamaha models.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Yamaha F50 50 4-Stroke 2007+ 63D-W0078-03-00 Superseded 63D-W0078-01-00
Yamaha F60 60 4-Stroke 2007+ 63D-W0078-03-00 Superseded 63D-W0078-01-00
Yamaha F70 70 4-Stroke 2007+ 63D-W0078-03-00 Superseded 63D-W0078-01-00
Yamaha F90 90 4-Stroke 2007+ 63D-W0078-03-00 Superseded 63D-W0078-01-00
Yamaha 40-90 Series 40-90 2-Stroke 1984+ 63D-W0078-03-00 Superseded 63D-W0078-01-00

Technical Specs

Product Type
Water Pump Impeller Repair Kit
Installation
Lower Unit / Gear Case
Dimensions
15.5" L x 12.0" W x 10.0" H
Weight
8.32 ounces (236 grams)

What’s in the Box

  • 1 x Water Pump Impeller
  • 1 x Wear Plate
  • Gaskets (multiple)
  • O-rings (multiple)
  • 1 x Woodruff Key
  • 4 x Bolts

Installation Notes

  1. Disconnect the battery and shift the outboard into neutral.
  2. Remove the lower unit (gear case) by unbolting it from the engine's midsection. Note the bolt locations and sizes.
  3. Place the lower unit on a suitable workbench and remove the water pump housing bolts.
  4. Slide the housing up and off the driveshaft. Remove the old impeller, Woodruff key, and wear plate.
  5. Thoroughly clean all mating surfaces, ensuring all old gasket material is removed.
  6. Install the new gaskets and wear plate. Insert the new Woodruff key into the driveshaft slot.
  7. Align the keyway and slide the new impeller onto the driveshaft.
  8. Apply a light coat of marine grease to the inside of the pump housing.
  9. Install the housing over the impeller, turning the driveshaft clockwise to help seat the impeller vanes correctly.
  10. Secure the housing with the new bolts, tightening them to the manufacturer's specified torque in a crisscross pattern.
  11. Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are properly aligned.

Troubleshooting & FAQ

How do I know if this kit fits my specific Yamaha model?

The surest way is to match your engine's original part number to one of the numbers listed in our Part Number Matrix. You can also consult the Engine & Model Compatibility table. If your model or year is not explicitly listed, we recommend verifying with your service manual before ordering.

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 water stream from the "telltale" outlet, or receiving a high engine temperature alarm from your controls.

How often should a water pump impeller be replaced?

For preventative maintenance, most manufacturers recommend replacing the impeller every 1 to 2 years or every 100 to 200 hours of operation, whichever comes first. This interval can be shorter if you frequently operate in sandy or silty water.

Is everything needed for the job included in this kit?

This kit includes all the core components for a standard water pump service: impeller, gaskets, plates, and hardware. You will still need your own tools and appropriate marine-grade grease or sealant as specified by your engine's service manual.

What is the difference between an OEM and an aftermarket part?

This listing is for an aftermarket replacement part, not a Genuine Yamaha (OEM) product. It is engineered to meet or exceed OEM specifications using comparable materials and is manufactured in an ISO 9002 certified facility. We batch-inspect parts to ensure quality and fitment.

What is your shipping speed and cost?

We ship worldwide quickly, with typical transit times of 5–15 days for most regions. Standard shipping is free. Expedited shipping options, if available for your location, will be presented at checkout.

What is the warranty and return policy?

This part is covered by a 1-year warranty against manufacturing defects under normal marine use. 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 policy page or reach out for instructions.

Safety & Important Info

  • Verify images and specifications against your original part before installation. If anything differs—even if your model appears on the compatibility list—do not purchase or install.
  • This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component. All mentions of brand names and part numbers are for reference purposes only.
  • Professional installation by a qualified marine mechanic 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 high-quality marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.
  • Fast Global Fulfillment — With warehouses worldwide, we offer free standard delivery to most regions in 5–15 days, getting you back on the water sooner.
  • Manufacturer-Direct Value — By working directly with manufacturers, we provide fair, transparent pricing without compromising on materials or quality control.

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