6H4-44352 Water Pump Impeller for Yamaha C30 F25 T25 F30 F40 | JLM Marine

Water Pump Impeller – Fits Yamaha 2-Stroke & 4-Stroke 25–40 HP Outboards

This high-performance water pump impeller is designed for Yamaha outboard engines ranging from 25 HP to 40 HP, covering both 2-stroke and 4-stroke models from 1987 to 2017. Engineered to meet OEM specifications, it ensures reliable cooling system performance and engine protection across a wide range of Yamaha motor configurations including C30, F25, T25, F30, and F40 series.

Direct replacement for Yamaha OEM part numbers 6H4-44352, 6H4-44352-01, and 676-44532-01, as well as aftermarket equivalents Sierra P/N 18-3068 and CEF P/N 500385. This impeller provides comprehensive coverage for vintage and modern Yamaha outboards.

• 6-blade neoprene rubber construction for maximum durability and chemical resistance
• Hardened nylon insert engineered for long-lasting performance in marine environments
• Precision dimensions: 55.48 mm external diameter, 16.10 mm shaft insert diameter

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 × Outboard Water Pump Impeller

Installation Guide

1. Disconnect the fuel line and remove the spark plug wires to ensure the engine cannot start during service.
2. Remove the lower unit from the outboard motor according to your engine's service manual. This typically involves draining the gear oil and detaching mounting bolts.
3. Locate and disassemble the water pump housing by removing the screws or bolts securing the pump cover and plate.
4. Extract the old impeller carefully, noting the direction of blade curvature for proper reinstallation.
5. Inspect the pump housing and plate for wear, scoring, or corrosion; clean all surfaces thoroughly and replace any damaged components.
6. Lubricate the new impeller blades with marine-grade glycerin, soapy water, or outboard lower unit oil—never use petroleum-based grease.
7. Install the new impeller with blades curved in the correct rotational direction, ensuring it seats fully onto the driveshaft splines.
8. Reassemble the pump housing, plate, and gaskets in reverse order, using new gaskets and O-rings where applicable.
9. Reinstall the lower unit, tightening all mounting bolts to factory torque specifications and refilling with the correct gear oil.
10. Reconnect fuel lines and spark plug wires, then test the cooling system by running the engine in a water barrel or on the hose.
11. Verify strong water flow from the telltale (pilot) hole within 15–30 seconds of starting the engine.
12. Dispose of the old impeller and fluids responsibly and record the service date for future maintenance tracking.

Troubleshooting & FAQ

How do I confirm this impeller fits my Yamaha engine?
Cross-reference your engine model and year with the compatibility table above. You can also verify by matching the OEM part number stamped on your original impeller or by checking Yamaha's exploded parts diagrams for your specific motor serial number.

How often should I replace the water pump impeller?
Yamaha recommends inspecting the impeller annually and replacing it every 2–3 years or 200–300 operating hours, whichever comes first. If you operate in sandy, silty, or debris-laden water, inspect and replace more frequently to prevent overheating damage.

What are the signs that my impeller is failing?
Common symptoms include weak or no water flow from the telltale hole, engine overheating, steam from the powerhead, or the temperature alarm sounding. Inspect the impeller immediately if you notice any of these issues to avoid serious engine damage.

Can I use petroleum jelly or grease to lubricate the impeller during installation?
No—petroleum-based products can damage neoprene rubber and cause premature failure. Always use marine-grade glycerin, biodegradable soapy water, or outboard lower unit gear oil for lubrication during assembly.

Will this impeller work if my engine model is not listed in the compatibility table?
If your model is not listed, do not assume compatibility. Compare the physical dimensions (external diameter, shaft insert diameter, blade count) and OEM part number with your original impeller before ordering.

Is this an OEM part or an aftermarket replacement?
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.