Water Pump Repair Kit – Fits Yamaha 2-Stroke C55 Outboards (Replaces 663-W0078-01-00)

$29.95 $47.00

Shipping calculated at checkout.

Water Pump Repair Kit – Fits Yamaha 2-Stroke C55 Outboards (Replaces 663-W0078-01-00) is backordered and will ship as soon as it is back in stock.

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 Repair Kit – Fits Yamaha 2-Stroke C55 Outboards (Replaces 663-W0078-01-00) is designed for Yamaha C55 2-stroke outboard engines with 55 HP, specifically for models manufactured between 1992 and 1994. It provides the essential components to restore your engine's cooling system performance.

It serves as a direct replacement for Yamaha OEM part number 663-W0078-01-00.

Engineered for direct OEM replacement installation.
Designed for 2-stroke outboard marine engine applications.
Includes a new impeller, gaskets, plates, and hardware for a complete overhaul.

Part Number Matrix

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

Brand	Part Number
Yamaha	663-W0078-01-00

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Yamaha	C55	55	2-Stroke	1992–1994	663-W0078-01-00

Technical Specs

Product Type: Water Pump Repair Kit
Installation: Direct OEM replacement
Dimensions: 15.0" L x 12.0" W x 9.0" H
Other Technical Attributes: For 2-stroke outboard marine engines

What’s in the Box

1 x Cartridge Insert (663-44322-00-00)
1 x Impeller (6H3-44352-00-00)
1 x Water Pump Gasket (663-44315-A0-00)
1 x Cartridge Outer Plate (663-44323-00-00)
1 x Cartridge Gasket (663-44324-A0-00)
2 x Bolts (97095-08055-00)
2 x Bolts (97095-08045-00)
1 x Water Seal Damper 2 (663-44366-00-00)
1 x Woodruff Key (90280-03M03-00)

Installation Notes

Disconnect the battery and remove the engine cover.
Shift the engine into neutral and remove the bolts securing the lower unit (gearcase).
Carefully lower the gearcase to access the water pump housing.
Remove the water pump housing bolts and lift the housing to expose the impeller.
Remove the old impeller, gaskets, plates, and seals. Clean all mating surfaces thoroughly.
Install the new components from the kit in the reverse order of removal, ensuring the impeller vanes are oriented correctly.
Apply a light coat of marine grease to the new impeller and inside the housing.
Reinstall the water pump housing, ensuring all gaskets are properly seated.
Reattach the lower unit to the engine, making sure the driveshaft and water tube align.
Reconnect the battery and start the engine in a water source to test for proper water flow from the tell-tale outlet.

Troubleshooting & FAQ

How do I know if this kit fits my Yamaha C55?

This kit is specifically for Yamaha C55 models made between 1992 and 1994. Please note that earlier C55 models (1990–1991) require a different kit (part no. 663-W0078-A0-00). Always verify your engine's year and model before purchasing.

What are the signs of a failing water pump?

Common symptoms include a weak or non-existent water stream from the "tell-tale" outlet, engine overheating alarms, or a noticeable decrease in engine performance. A visual inspection may reveal a brittle, cracked, or deformed impeller.

How often should I replace my water pump impeller?

As a general maintenance guideline, it is recommended to inspect and/or replace the water pump impeller every 100-200 hours of operation or at least once per season, whichever comes first. This interval can vary based on operating conditions like water quality (sandy or silty water causes faster wear).

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.

Payment & Security

Payment methods

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.