Water Pump Impeller Gasket – Fits Yamaha 40HP 2-Stroke C40 (Replaces 676-44324-A0)

Product Details

This Water Pump Impeller Gasket is designed for Yamaha 40HP 2-Stroke C40 outboard engines from 1990–1997, as well as select OMC Cobra stern drive models (235 and 240). Engineered as a direct-fit aftermarket replacement, this gasket ensures reliable sealing within the water pump housing to prevent leaks and maintain optimal cooling performance.

This gasket directly replaces Yamaha OEM part numbers 676-44324-A0, 676-44324-A0-00, and 676-44324-A1, offering seamless cross-reference compatibility.

• Essential seal for water pump impeller housing integrity
• Precision-cut to OEM dimensions for drop-in installation
• Compatible with both outboard and stern drive applications

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Part Type

Water Pump Impeller Gasket

Material

Rubber composite sealing material

OEM Replacement For

Yamaha 676-44324-A0, 676-44324-A0-00, 676-44324-A1

Application

Yamaha 40HP 2-Stroke outboards (C40); OMC Cobra stern drives (235, 240)

What's in the Box

• 1 × Gasket 676-44324-A0

Installation Notes

1. Disconnect battery and remove lower unit per manufacturer service manual procedures.
2. Remove water pump housing cover and carefully lift out the impeller assembly.
3. Clean all mating surfaces thoroughly, removing old gasket material and debris.
4. Inspect impeller and housing for wear or damage; replace components as needed.
5. Position the new gasket evenly onto the pump housing, ensuring proper alignment with all bolt holes.
6. Lubricate the impeller with glycerin or water-pump grease before reinstalling.
7. Reinstall the impeller, rotating it gently to ensure blades seat correctly within the housing.
8. Torque housing bolts to manufacturer specifications in a star pattern to ensure even clamping pressure.
9. Reinstall the lower unit, reconnect the battery, and perform a water flow test before use.

Troubleshooting & FAQ

How do I know if my water pump gasket needs replacement?

Signs include coolant leaks around the pump housing, overheating due to poor seal integrity, visible gasket deterioration during impeller service, or age-related hardening. Replace the gasket anytime you service the impeller to ensure proper sealing.

Can I reuse the old gasket during impeller replacement?

No. Gaskets are single-use components. Reusing a compressed or degraded gasket can cause leaks and lead to engine overheating. Always install a new gasket when servicing the water pump assembly.

Is this gasket compatible with both outboard and stern drive applications?

Yes. This gasket fits Yamaha 40HP 2-Stroke C40 outboards (1990–1997) and select OMC Cobra stern drive models (235 and 240 from the 1970s). Confirm your engine model and year before ordering.

What happens if the gasket is installed incorrectly?

Improper alignment can cause coolant leaks, reduced water flow, or uneven clamping that leads to premature gasket failure. Ensure the gasket is seated evenly and all bolt holes align before tightening the housing cover.

How often should this gasket be replaced?

Replace the gasket every time you service or replace the water pump impeller, typically every 2–3 years or 200–300 hours of operation, whichever comes first. Frequent saltwater use may require more frequent replacement.

Does this gasket require any sealant during installation?

Typically no additional sealant is required if the gasket and mating surfaces are clean and undamaged. Consult your engine's service manual for specific recommendations. Some technicians apply a thin film of grease to aid installation and prevent sticking.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

• Verify images/specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended for safety and performance.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
• Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
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