Water Pump Impeller Kit – Fits Yamaha T25, F30, F40 (2000-2009) (Replaces 66T-W0078-00-00)

Water Pump Impeller Kit – Fits Yamaha T25, F30, F40 (2000-2009) (Replaces 66T-W0078-00-00)

This kit is designed for select Yamaha 4-Stroke engines, including T25 (2001-2019), F30 (2001-2005), and F40 (2000-2008) models. It also fits certain Yamaha 2-Stroke engines, such as the 40X, 40XWT, and E40X series from 1998 onwards.

This is a direct replacement for Yamaha OEM part numbers 66T-W0078-00-00 and 66T-W0078-01-00. It also replaces Sierra parts 18-3413 and 18-3440, as well as other aftermarket numbers like MAL9-48610 and AM66T-W0078-00.

• Includes a complete set of components for a full water pump service: impeller, housing, gaskets, and hardware.
• Features a durable 6-blade neoprene impeller for reliable water flow.
• Designed as a direct-fit replacement for straightforward installation.

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

Installation Guide

1. Disconnect the negative battery terminal and ensure the engine is off.
2. Remove the lower unit (gearcase) from the outboard motor.
3. Unbolt and remove the old water pump housing assembly, noting the order of the components.
4. Clean the mating surfaces thoroughly, removing any old gasket residue.
5. Install the new components from the kit, starting with the woodruff key and impeller. Ensure the impeller vanes are turned in the correct rotational direction.
6. Assemble the new water pump housing and gasket, applying a light coat of marine grease to the interior.
7. Torque the housing bolts to the manufacturer's specified values.
8. Reinstall the lower unit, ensuring all connections are secure.
9. Start the engine in a water-filled test tank or with a hose flush attachment to verify proper water flow from the tell-tale.

Troubleshooting & FAQ

Q: How can I be sure this kit fits my specific Yamaha engine?

A: The best way is to match your engine's model and year to the "Compatible Engine Models" table. Also, cross-reference your existing part number with our "Part Number Cross-Reference" table. When in doubt, use the Yamaha Serial Number Guide linked above to confirm your model details.

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

A: Common signs include the engine overheating at idle or low speeds, a weak or non-existent "tell-tale" water stream, and a brittle, cracked, or melted appearance on the old impeller upon inspection.

Q: How often should I replace the water pump impeller?

A: For preventative maintenance, it is recommended to replace the impeller and gaskets every 100-200 operating hours or at least once per year, whichever comes first. This is especially important if you operate in saltwater or sandy/silty conditions.

Q: OEM vs. Aftermarket?

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.