679-44316-A0 Water Pump Impeller Gasket for Yamaha C40 | JLM Marine

Water Pump Impeller Gasket – Fits Yamaha 2-Stroke 40 HP C40 Outboard | 679-44316-A0

This water pump impeller gasket is designed for Yamaha 2-stroke 40 HP outboard engines, specifically the C40 series (1990–1997). It also fits select OMC Cobra stern drive models (235 and 240) from the 1970s. Engineered to create a reliable seal within the water pump housing, this gasket helps maintain optimal cooling system performance and prevents leaks during operation.

This gasket directly replaces Yamaha OEM part numbers 679-44316-A0 and 679-44316-A1, ensuring seamless compatibility with your original equipment. It is an essential component for routine water pump maintenance and rebuild procedures.

• Direct replacement for Yamaha part numbers 679-44316-A0 and 679-44316-A1
• Suitable for both Yamaha outboard engines and OMC Cobra stern drives
• Critical gasket for water pump rebuild and maintenance

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

Your purchase includes:

• 1 × Water Pump Impeller Gasket (679-44316-A0)

Installation Guide

1. Disconnect the fuel line and remove the engine cowling to access the lower unit. Ensure the engine is completely off and cool before starting.
2. Remove the lower unit by disconnecting the shift linkage and unbolting the mounting hardware. Carefully separate the lower unit from the mid-section.
3. Access the water pump housing by removing the propeller, propeller shaft, and any retaining components securing the pump assembly.
4. Disassemble the water pump by removing the pump housing bolts and separating the housing from the lower unit. Take note of the orientation of all components.
5. Remove the old impeller gasket from the mating surfaces. Clean all residue, old gasket material, and debris thoroughly using a gasket scraper and solvent.
6. Inspect all water pump components including the impeller, housing, and wear plate for damage or excessive wear. Replace any worn parts as needed.
7. Position the new gasket (679-44316-A0) onto the clean, dry mating surface, ensuring proper alignment with all bolt holes and passages.
8. Reassemble the water pump housing by installing the impeller (lubricate with glycerin or soapy water) and securing the housing with bolts in a star pattern to ensure even torque.
9. Reinstall the lower unit onto the mid-section, reconnecting the shift linkage and tightening all mounting bolts to manufacturer specifications.
10. Reattach the propeller shaft and propeller, ensuring all hardware is properly secured and torqued to specification.
11. Reconnect the fuel line and replace the engine cowling. Perform a visual inspection to ensure all connections are secure.
12. Test the cooling system by running the engine in a test tank or on-water and verifying proper water discharge from the telltale indicator.

Troubleshooting & FAQ

Q: How do I confirm this gasket fits my Yamaha engine?
A: Verify your engine model is a Yamaha C40 40 HP 2-stroke manufactured between 1990 and 1997. Cross-reference your current gasket's part number with 679-44316-A0 or 679-44316-A1, or consult the Yamaha parts diagram for your specific serial number.

Q: How often should I replace the water pump impeller gasket?
A: Replace the gasket every time you service or rebuild the water pump assembly, typically every 2–3 years or 200–300 hours of operation. Always use a new gasket during impeller replacement to ensure a proper seal and prevent leaks.

Q: What are the signs that this gasket needs replacement?
A: Common symptoms include visible coolant leaks around the water pump housing, reduced water flow from the telltale indicator, engine overheating, or water contamination in the lower unit. If you notice any of these issues, inspect and replace the gasket immediately.

Q: Can I reuse the old gasket if it looks undamaged?
A: No, it is not recommended to reuse old gaskets even if they appear intact. Gaskets compress and conform to mating surfaces during use, and reusing them can result in improper sealing, leaks, and potential engine damage.

Q: Will this gasket fit OMC Cobra stern drive models?
A: Yes, this gasket is compatible with OMC Cobra 235 (1971, 1975–1977) and 240 (1978) stern drive models. Confirm your model and year match the compatibility table before ordering.

Q: Is this an OEM or aftermarket gasket?
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.