Water Pump Impeller Kit with Housing – Fits Yamaha 40-60 HP (Replaces 63D-W0078-01-00, Sierra 18-3415)

Water Pump Impeller Kit with Housing – Fits Yamaha 40-60 HP (Replaces 63D-W0078-01-00, Sierra 18-3415)

This complete water pump repair kit is designed for select Yamaha 2-stroke and 4-stroke outboard motors. It provides a reliable solution for maintaining your engine’s cooling system, fitting 2-Stroke models from 40-50 HP (1995–2009) and 4-Stroke models from 40-60 HP (1995–2009).

This kit serves as a direct replacement for Yamaha part numbers 63D-W0078-01-00 and 63D-W0078-03-00, as well as Sierra part numbers 18-3415 and 18-3434, ensuring compatibility and performance.

• Includes everything needed for a full replacement: housing, impeller, plate, gasket, and hardware.
• Engineered for lower unit installation.
• Features a durable Nylon PA66 plastic housing and a high-performance neoprene rubber impeller.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Yamaha owners, here’s a guide to help you identify your engine’s serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Water Pump Housing (63D-44311-00-00)
• 1 x Neoprene Impeller (6H3-44352)
• 1 x Insert Cup (63D-44322-00-00)
• 1 x Wear Plate (63D-44323-00)
• 1 x Pump Case Gasket (63D-44316-00-00)
• 4 x Bolts (90119-08M15-00)
• 1 x Impeller Key (90280-03024-00)
• 1 x Water Seal Damper (18-1830)
• 1 x Cover, Water Pump Housing (63D-44312)
• 1 x O-Ring (93210-59MG7)

Installation Guide

For a successful installation, follow these general steps. Professional installation is always recommended.

1. Disconnect Battery: Ensure the engine is off and disconnect the battery cables to prevent accidental starting.
2. Drain Gearcase Oil: Place a drain pan under the lower unit and remove the drain and vent screws to drain the gearcase lubricant.
3. Remove the Lower Unit: Unbolt the lower unit from the upper casing. This may also require disconnecting the shift linkage.
4. Access the Water Pump: With the lower unit removed, locate and unbolt the water pump housing.
5. Remove Old Components: Carefully remove the old housing, impeller, wear plate, gaskets, and seals. Note the orientation of the impeller vanes.
6. Clean All Surfaces: Thoroughly clean the mounting surfaces on the driveshaft and lower unit to ensure a proper seal.
7. Install New Components: Assemble the new kit components in reverse order. Lightly grease the impeller and insert cup. Ensure the impeller key is correctly seated.
8. Re-attach Lower Unit: Bolt the lower unit back onto the engine, reconnecting any linkages. Torque bolts to manufacturer specifications.
9. Refill Gearcase Oil: Fill the lower unit with the specified marine gear lubricant until it flows from the upper vent hole, then replace both screws.
10. Test Operation: Reconnect the battery. Start the engine in a safe environment with a water supply (like on "earmuffs") and verify a steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this fits my engine?

First, check the "Compatible Engine Models" table on this page to see if your engine's model and year range are listed. Next, verify that your existing part number matches one of the numbers in our "Part Number Cross-Reference" section. Comparing the product images to your old part is also a critical final step.

What are the signs of a failing water pump impeller?

The most common sign is a weak or non-existent water stream from the "tell-tale" outlet. Other symptoms can include the engine overheating alarm sounding or the engine running hotter than usual. Reduced performance can also be an indicator.

How often should I replace the water pump impeller?

For preventative maintenance, it is highly recommended to replace your impeller every year or every 100 hours of operation, whichever comes first. This is especially important if you operate in saltwater or water with heavy sediment.

OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.