Water Pump Impeller Kit – Fits Yamaha 40/50/60HP 2-Stroke & 4-Stroke (Replaces 63D-W0078-01)

Water Pump Impeller Kit – Fits Yamaha 40/50/60HP 2-Stroke & 4-Stroke (Replaces 63D-W0078-01)

This complete water pump impeller repair kit provides everything needed for a full service of the lower unit water pump. It is designed for a wide range of Yamaha 2-stroke and 4-stroke outboard engines, ensuring reliable performance and cooling.

This kit is a direct aftermarket replacement for Yamaha OEM part numbers 63D-W0078-01-00, 63D-W0078-03-00, 63D-W0078-02-00, and others, offering a high-quality alternative for routine maintenance or repair.

• Engine Compatibility: Fits select Yamaha 40, 50, and 60 HP models (2-Stroke and 4-Stroke).
• Installation Location: Mounts in the lower unit/gearcase assembly.
• Quality Standard: Manufactured in an ISO9002 certified facility to meet or exceed OEM specifications.

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.

Yamaha 2-Stroke Models

Yamaha 4-Stroke Models

Technical Specifications

Package Contents

• 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 Bolt with Washer (90119-08M15-00)
• 1 x Water Seal Damper (663-44366-00-00)
• 1 x Woodruff Key (90280-03024-00)

Installation Guide

1. Disconnect the battery and shift the outboard motor into the neutral position.
2. Locate and remove the mounting bolts that secure the lower unit (gearcase) to the engine's midsection.
3. Carefully lower and separate the gearcase from the rest of the outboard.
4. Unbolt and remove the old water pump housing to access the impeller.
5. Remove the old impeller, wear plate, and gaskets, taking note of their correct orientation.
6. Thoroughly clean all mating surfaces on the gearcase and housing.
7. Install the new gasket, wear plate, and Woodruff key onto the driveshaft.
8. Slide the new impeller onto the driveshaft, turning clockwise to seat the vanes correctly inside the housing cup.
9. Install the new housing, cartridge, and seals, ensuring everything is properly aligned.
10. Secure the new housing with the provided bolts, tightening them to the manufacturer's recommended torque specifications.
11. Carefully re-install the lower unit onto the engine and tighten the mounting bolts.
12. Reconnect the battery and test the engine using a reliable water source (flushing muffs or in the water) to verify proper water flow from the tell-tale port.

Troubleshooting & FAQ

Question: How do I confirm this kit fits my engine?

Answer: This kit is designed for a specific range of Yamaha 40, 50, and 60 HP 2-stroke and 4-stroke outboards. Please review the detailed "Compatible Engine Models" tables on this page and compare your engine's model and year. Verifying the OEM part number (63D-W0078-01) against your service manual is the most reliable method of confirming fitment.

Question: What are the signs of a failing water pump impeller?

Answer: Common signs of a worn or failing impeller include a weak or inconsistent stream of water from the tell-tale outlet, frequent engine overheating alarms, or discovering a brittle, cracked, or deformed impeller during a visual inspection.

Question: How often should I replace my water pump kit?

Answer: For preventative maintenance, it is recommended to inspect and/or replace your water pump impeller and components every one to two years, or every 100-200 hours of operation. This interval can vary based on usage conditions, particularly in saltwater or silty environments.

Question: OEM vs. Aftermarket?

Answer: 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.

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

Answer: 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.

Question: What is your warranty and return policy?

Answer: 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.