Water Pump Impeller Kit – Fits Yamaha F30, F40, T25 4-Stroke Outboard (Replaces 66T-W0078-00)

Water Pump Impeller Kit – Fits Yamaha F30, F40, T25 4-Stroke Outboard (Replaces 66T-W0078-00)

This water pump impeller service kit provides a complete solution for replacing the water pump components on select Yamaha 4-stroke outboard engines. It is designed to fit T25, F30, and F40 horsepower models manufactured primarily between 2000 and 2008, with some models having extended compatibility. Please consult the engine compatibility list to verify your specific model and year.

Engineered as a direct replacement for OEM assemblies, this kit ensures proper fit and function, restoring your cooling system's performance and reliability. It is compatible with several Yamaha outboard engine configurations and provides a comprehensive set of parts for a full service.

• Includes a new impeller, housing, wear plate, gaskets, and all necessary hardware for a complete installation.
• Made with marine-grade metal and a durable neoprene rubber impeller to withstand the harsh saltwater environment.
• Direct replacement installation requires no specialized modifications.

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

This comprehensive kit includes all the necessary components for a full water pump service:

• 1 x Pump Housing (66T-44311-00-00)
• 1 x Water Pump Impeller (6H4-44352-00-00/6H4-44352-02-00)
• 1 x Cartridge Insert (63D-44322-00-00)
• 1 x Outer Plate (66T-44323-00-00)
• 1 x Gasket (63D-44316-00-00)
• 1 x Cover/Pump Housing Cover (63D-44312-00-00)
• 1 x Woodruff Key (90280-03M03-00)
• 1 x O-ring (93210-59MG7-00)
• 1 x Seal/Water Seal Damper (663-44366-00-00)
• 4 x Bolts/Washer (90119-08M15-00)

Installation Guide

1. Disconnect Power: Disconnect the battery and shift the outboard into neutral.
2. Remove Lower Unit: Remove the bolts securing the lower unit (gearcase) to the engine's upper section and carefully lower it.
3. Access Pump: Unbolt and remove the old water pump housing to expose the impeller.
4. Remove Old Components: Take out the old impeller, woodruff key, wear plate, and any gaskets or seals. Clean all mating surfaces thoroughly.
5. Install New Components: Place the new gasket and wear plate onto the driveshaft. Slide the new woodruff key into its slot on the shaft.
6. Install Impeller: Lubricate the new impeller and the inside of the pump housing with marine grease. Install the impeller onto the driveshaft, turning the shaft clockwise to bed the vanes correctly.
7. Install Housing: Fit the new pump housing cover, insert, and o-ring/seals. Secure the new housing with the provided bolts, tightening them to the manufacturer's recommended torque.
8. Reassemble & Test: Reinstall the lower unit, ensuring the water tube aligns correctly. Once assembled, start the engine with a proper water supply and verify a steady stream of water from the tell-tale port.

Troubleshooting & FAQ

Q: How can I be sure this kit fits my exact Yamaha engine?
A: The most reliable method is to check your engine's model and year against our compatibility table. You can find your model information on the engine's identification tag. For additional certainty, use the Yamaha Serial Number Guide and Parts Catalog links provided above to cross-reference the OEM part number (66T-W0078-00) with your specific engine diagram.

Q: What are the signs of a failing water pump impeller?
A: Common symptoms include a weak or intermittent water stream from the "tell-tale" outlet, engine overheating alarms, or visible cracks, stiffness, or missing blades on the old impeller upon inspection.

Q: How often should I replace the water pump impeller?
A: As a general maintenance rule, it is recommended to inspect and/or replace the impeller every 1-2 years or every 100-200 hours of use, depending on operating conditions (e.g., saltwater vs. freshwater, sandy/silty water). Proactive replacement prevents engine damage from overheating.

Q: Is this an OEM part or an aftermarket part?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.