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

Quicksilver 75692Q2 is a direct-fit replacement thermostat kit for select Mercury and Mariner V6 outboards (135–200hp) designed to restore correct engine coolant regulation.

This OEM Quicksilver kit contains two thermostats and two rubber gaskets and targets specific Mercury/Mariner V6 models and serial ranges. Installing the correct thermostat helps maintain the engine's operating temperature, which supports reliable performance and long-term durability. Always confirm your engine’s serial number and follow the manufacturer’s service instructions for removal and installation.

Which engines and serial numbers does this thermostat kit fit?

The 75692Q2 kit fits 135–150hp V6 Mercury and Mariner outboards with serial numbers A9046446 and higher, 175hp V6 units with serial C100861 and higher, and 200hp V6 units with serial 6435503 and higher. Verify the serial on your engine cowling or in the owner’s manual to ensure compatibility. If your engine falls outside these ranges, consult your dealer or service manual for the correct thermostat part.

• Fits 135–150hp V6: serial No. A9046446 and up
• Fits 175hp V6: serial No. C100861 and up
• Fits 200hp V6: serial No. 6435503 and up
• Includes two thermostats and two rubber gaskets for full replacement

How does replacing the thermostat improve engine operation?

A properly functioning thermostat helps the engine reach and hold the intended operating temperature quickly and consistently. This stabilizes combustion efficiency, reduces wear from running too cold or too hot, and supports optimal power output. Replacing a failed thermostat prevents overheating and potential engine damage when cooling flow is restricted.

• Restores proper coolant flow and temperature control
• Helps prevent overheating and excessive wear
• Contributes to consistent power and fuel efficiency

What’s included and what should I prepare for installation?

The kit ships with two thermostats and two rubber gaskets—one set per cylinder bank as required for these V6 outboards. Use the temperature-specific thermostat recommended in your owner's or service manual. Prepare basic hand tools, a clean work area, and reference the service manual for torque specs and sequence to ensure a leak-free seal.

• Kit: 2 thermostats + 2 rubber gaskets
• Use temperature-specified thermostat per manual
• Have tools, gasket scraper, and manufacturer torque values ready

Are these Quicksilver parts genuine OEM replacements?

Yes — Quicksilver supplies original-equipment-quality parts for Mercury Marine engines and follows the testing standards used by the manufacturer. Choosing this Quicksilver kit ensures the thermostats match factory specifications for fit, material, and performance. That reduces the risk of premature failures often associated with untested aftermarket components.

• OEM-grade design and materials from Quicksilver
• Tested to match Mercury Marine specifications
• Backed by decades of industry service and parts support

Who is this for: This Quicksilver 75692Q2 thermostat kit is intended for boat owners, marine technicians, and service shops maintaining Mercury or Mariner V6 outboards in the specified serial ranges. It’s suited for those replacing an old or failed thermostat as part of routine cooling-system maintenance or after discovering temperature regulation issues. If you’re unsure about fitment, check the engine serial number or consult a certified Mercury service provider before purchase.