Quicksilver Replacement Thermostat Kit for Mercury/Mariner 135-200hp V6 — 75692Q2, 2 Thermostats & Gaskets

Quicksilver 75692Q2 is a direct-fit replacement thermostat kit engineered for select Mercury and Mariner V6 outboards from 135 to 200 horsepower.

If your engine cooling is underperforming or your service manual lists 75692Q2 as the correct part, this genuine Quicksilver thermostat kit restores proper coolant regulation and maintains intended operating temperature ranges. Quicksilver, the OEM supplier to Mercury Marine, designs and tests its parts to match factory specifications so your outboard runs as intended without guesswork.

Which engines and serial ranges use the 75692Q2 thermostat?

This kit fits specific Mercury and Mariner V6 outboards: 135–150hp units with serial A9046446 and up, 175hp units with serial C100861 and up, and 200hp units with serial 6435503 and up. Always verify the part number against your owner's or service manual to confirm compatibility before ordering or installing.

• 135–150hp V6: serial No. A9046446 and higher
• 175hp V6: serial No. C100861 and higher
• 200hp V6: serial No. 6435503 and higher
• Check your manual for specific application notes and install steps

What comes in the Quicksilver 75692Q2 kit and why it matters?

The kit includes two thermostats and two rubber gaskets—one thermostat and gasket per bank—so you replace the complete set used on V6 heads. Replacing both thermostats at once helps ensure balanced cooling across cylinders and avoids mixing old and new components that can compromise performance.

• Two thermostats for both engine banks
• Two rubber gaskets for reliable sealing
• Factory-quality materials match original equipment specifications
• Sold as a complete set to streamline service procedures

How does the thermostat affect engine performance and longevity?

The thermostat regulates coolant flow to maintain the engine within its designed temperature window. Correct operating temperature promotes fuel efficiency, consistent power delivery, and faster warm-up while reducing thermal stress on components.

• Maintains optimal engine temperature for efficient combustion
• Prevents overcooling or overheating that can harm components
• Supports stable operating conditions for emissions and performance
• Factory match minimizes leak and fitment issues

How should I replace the thermostat and what precautions are needed?

Refer to your owner's or service manual for step-by-step removal and installation instructions specific to your outboard model. Work on a cool engine, follow torque specs, and inspect mounting surfaces and coolant passages for debris before seating new gaskets and thermostats.

• Follow the service manual for removal of the old thermostat
• Install new gaskets and torque bolts to factory specs
• Flush cooling passages if necessary before installation
• Start and warm the engine to check for leaks and proper operation

Who this is for: Boat owners, marine technicians, and do-it-yourselfers who operate Mercury or Mariner V6 outboards in the 135–200hp range and need an OEM-grade replacement thermostat. Choose Quicksilver 75692Q2 when you want a factory-matched part that simplifies servicing, reduces the risk of fitment issues, and helps restore correct engine cooling behavior without compromise.