Water Pump Impeller – Fits Yamaha 25-50 HP Outboards (Replaces 6H4-44352-02-00)

Water Pump Impeller – Fits Yamaha 25–50 HP Outboards (Replaces 6H4-44352-02-00)

This water pump impeller is designed for Yamaha 2-stroke outboard models from 25 HP to 50 HP (1984–2002) and 4-stroke models from 25 HP to 40 HP (1998–2017). It ensures reliable engine cooling and performance for a wide range of Yamaha outboards, including C30, PRO50, JET50, F25, T25, F30, and F40 models.

It serves as a direct replacement for multiple Yamaha and Sierra part numbers, providing a precise fit and restoring original functionality. Made from a durable neoprene and hardened nylon composite, this impeller is engineered to meet or exceed OEM specifications for longevity and performance.

• Installation: Direct OEM replacement that fits the original housing.
• Material: Constructed from a robust blend of neoprene and hardened nylon for durability.
• Included Parts: Comes with the required impeller key for a complete 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.

Yamaha 2-Stroke Outboards

Yamaha 4-Stroke Outboards

Technical Specifications

Package Contents

• 1 x Impeller (6H4-44352-02-00)
• 1 x Impeller Key

Installation Guide

1. Disconnect Power: Disconnect the battery and spark plug wires to prevent accidental starting.
2. Drain the Lower Unit: Place a drain pan under the lower unit and remove the drain screw to empty the gear lube.
3. Remove Lower Unit: Unbolt and carefully detach the lower unit (gearcase) from the outboard housing.
4. Access the Water Pump: With the lower unit removed, locate and unscrew the bolts securing the water pump housing.
5. Remove Old Impeller: Lift the housing to expose the old impeller. Note its orientation and remove it, along with the old key, gaskets, and wear plates.
6. Clean and Inspect: Thoroughly clean the housing interior and inspect it for scoring, warping, or corrosion. Replace the housing if significant wear is found.
7. Install New Key and Impeller: Insert the new impeller key into the slot on the driveshaft. Slide the new impeller on, turning the driveshaft clockwise to bend the vanes correctly.
8. Reassemble Pump Housing: Place the new gaskets and wear plate, then secure the housing over the new impeller.
9. Reattach Lower Unit: Reinstall the lower unit to the outboard, ensuring the driveshaft and water tube align properly.
10. Refill Gear Lube: Fill the lower unit with the correct type and amount of marine gear lubricant.
11. Test Operation: Reconnect the battery and spark plugs. Start the engine in water and verify a steady stream of water is exiting the "telltale" port.

Troubleshooting & FAQ

Q: How do I confirm this impeller fits my exact engine model?

A: First, check the compatible engine tables on this page. For Yamaha owners, we highly recommend using our Yamaha Serial Number Guide to verify your model and year, which helps ensure an exact match.

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 intermittent water stream from the telltale port, and visible cracks or damage on the impeller vanes during inspection.

Q: How often should I replace my outboard's water pump impeller?

A: As a general maintenance rule, it is recommended to inspect the impeller annually and replace it every 1 to 2 years, or every 100-200 hours of use, depending on operating conditions (especially in saltwater or sandy/silty water).

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.