Yamaha - Thermostat - F90B VF90 - 6FP-12411-00-00 

Overview

The Yamaha Thermostat | 6FP-12411-00-00 is one of those parts that keeps your engine running at the right temperature without you noticing it—until something’s off. When it starts sticking or wearing out, you’ll see it in fluctuating temps, slow warm-up, or overheating. It controls when coolant flows through the engine, so it has to open and close at the right time every time. If your motor isn’t holding steady temperature, this is one of the first things worth checking.

Key Features

• Accurate Temperature Control – Regulates coolant flow to maintain proper engine operating temperature.

• OEM Fit Precision – Built to Yamaha specifications for correct operation and proper sealing.

• Supports Engine Efficiency – Helps maintain optimal combustion and consistent performance.

• Heat-Resistant Construction – Designed to handle continuous temperature cycles and marine conditions.

Engine & Boat Compatibility

• F90B 
• VF90 

FAQs

Q1: What are signs the thermostat is failing?
A: Overheating, running too cool, or fluctuating engine temperature are common signs.

Q2: Can a bad thermostat cause overheating?
A: Yes, especially if it sticks closed and restricts coolant flow.

Q3: Should I replace this during routine maintenance?
A: Yes, it’s a common service item when working on the cooling system.

Q4: Does this part require a gasket?
A: Yes, proper sealing is important to prevent leaks and ensure correct function.

Q5: Is installation difficult?
A: It’s usually straightforward with basic tools and proper cleaning of surfaces.

• Engine Application
  • F90B
  • VF90