Yamaha - Thermostat Gasket - Cooling System Seal - 6E9-12414-A1-00

Overview

I’ve learned the hard way not to reuse thermostat gaskets, especially on older Yamaha setups like the C40 and CV40. It might look fine at first, but once it’s compressed, it doesn’t seal the same twice. This gasket is what keeps the cooling system tight right around the thermostat housing. Put a fresh one in, and you avoid leaks and temperature issues before they even start.

Key Features

• Reliable Cooling System Seal – Keeps water contained within the thermostat housing for proper flow.
• Leak Prevention Design – Helps eliminate coolant leaks that can affect engine performance.
• Heat-Resistant Material – Built to handle engine temperature and continuous water exposure.
• Precision Cut Fitment – Designed to match Yamaha surfaces for proper sealing.
• Direct Yamaha Replacement – Ensures dependable installation and long-term reliability.

Engine & Boat Compatibility

Designed for Yamaha outboard engines utilizing thermostat-controlled cooling systems, including models such as C40 and CV40. Commonly used across mid-range Yamaha outboards in recreational and commercial applications. Suitable for freshwater and saltwater environments where proper sealing and temperature control are critical.

FAQ

Q: What are signs this thermostat gasket needs replacing?
A: Water leaks around the housing or inconsistent engine temperature are common signs.

Q: Should I replace this gasket every time I remove the thermostat cover?
A: Yes, it’s best to install a new gasket each time to ensure a proper seal.

Q: Any tips for installing this gasket?
A: Clean both surfaces thoroughly and align the gasket carefully before tightening.

Q: How does saltwater affect this gasket?
A: Salt buildup can impact sealing surfaces, so regular flushing and inspection help prevent issues.

Q: Can a bad gasket cause overheating?
A: Yes, leaks or poor sealing can disrupt water flow and lead to temperature problems.

• Supersessions
  6E9-12414-A0-00, 6E9-12414-01-00