Water Pump Repair Kit – Fits Yamaha 40-60HP (Replaces 63D-W0078-01-00, Sierra 18-3434)
Water Pump Repair Kit – Fits Yamaha 40-60HP (Replaces 63D-W0078-01-00, Sierra 18-3434) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
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Water Pump Repair Kit – Fits Yamaha 40-60HP (Replaces 63D-W0078-01-...
Water Pump Repair Kit – Fits Yamaha 40-60HP (Replaces 63D-W0078-01-00, Sierra 18-3434) is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit – Fits Yamaha 40/50/60HP 2-Stroke & 4-Stroke (Replaces 63D-W0078-01-00) provides all necessary components to restore your engine's cooling system. It is designed for a range of Yamaha outboard models, including 2-stroke 40-50HP engines from 1994–2005 and 4-stroke F40, F50, and F60 engines from 1997 and newer.
This kit serves as a direct replacement for Yamaha part number 63D-W0078-01-00 and Sierra Marine part 18-3434, ensuring a precise fit and reliable performance.
- Engineered for direct OEM-level fit and function.
- Restores cooling system performance to prevent overheating.
- Includes all essential gaskets, seals, and impeller for a complete overhaul.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 63D-W0078-01-00 |
| Sierra | 18-3434 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is compatible with the following Yamaha outboard engine models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 40 | 40 | 2-Stroke | 1995–2005 | 63D-W0078-01-00 | |
| Yamaha | C40 | 40 | 2-Stroke | 1997–2003 | 63D-W0078-01-00 | |
| Yamaha | P40 | 40 | 2-Stroke | 1998 | 63D-W0078-01-00 | |
| Yamaha | 50 | 50 | 2-Stroke | 1998–2009 | 63D-W0078-01-00 | |
| Yamaha | C50 | 50 | 2-Stroke | 1998–2001 | 63D-W0078-01-00 | |
| Yamaha | P50 | 50 | 2-Stroke | 1995–1996 | 63D-W0078-01-00 | |
| Yamaha | F40 | 40 | 4-Stroke | 1999 | 63D-W0078-01-00 | |
| Yamaha | F50 | 50 | 4-Stroke | 1997 & newer | 63D-W0078-01-00 | |
| Yamaha | F60 | 60 | 4-Stroke | 2002 & newer | 63D-W0078-01-00 |
Technical Specs
- Product Type
- Water Pump Repair Kit
- Installation
- Direct OEM Replacement
- Other Technical Attributes
- Water pump cooling system component
What’s in the Box
- 1 x Cartridge Insert (63D-44322-00-00)
- 1 x Impeller (6H3-44352-00-00)
- 1 x Water Pump Housing Cover (63D-44312-00-00)
- 1 x Cartridge Outer Plate (63D-44323-00-00)
- 1 x O-Ring (93210-59MG7-00)
- 1 x Water Pump Gasket (63D-44316-00-00)
- 4 x Bolts With Washers (90119-08M15-00)
- 1 x Water Seal Damper 2 (663-44366-00-00)
- 1 x Woodruff Key (90280-03024-00)
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Drain the engine's cooling system completely.
- Remove the lower unit (gearcase) from the outboard motor.
- Unbolt and remove the old water pump housing and its components. Note the order of disassembly.
- Thoroughly clean the mounting surfaces and inspect for any damage.
- Install the new gasket, plates, impeller, and key from the kit. Ensure the impeller vanes are oriented correctly.
- Secure the new housing, applying sealant to bolts if required by the service manual.
- Reinstall the lower unit, ensuring the driveshaft and water tube align correctly.
- Once reassembled, start the engine and verify a steady stream of water from the tell-tale outlet.
Troubleshooting & FAQ
How do I know if my water pump is failing?
Common signs of a failing water pump include the engine overheating at idle or low speeds, a weak or inconsistent water stream from the "tell-tale" outlet, or a complete lack of water flow. Visible damage to the old impeller, such as cracked or missing vanes, also indicates it's time for a replacement.
How often should I replace my water pump impeller/kit?
As a best practice for preventative maintenance, it is recommended to replace your water pump impeller or the entire repair kit every 1 to 2 years, or every 100-200 hours of operation, whichever comes first. This interval can be shorter if you frequently operate in sandy, silty, or saltwater environments.
Will this fit Yamaha F50 models made after 1997?
Yes, this kit is specified to fit Yamaha F50 4-Stroke models from 1997 and newer, and F60 models from 2002 and newer. Always double-check your engine's part number to ensure compatibility.
What is the difference between this kit and the original OEM version?
This is a high-quality aftermarket kit designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function. The materials and components are selected for durability and performance comparable to the factory original.
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
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