Mercury - Thermostat Yamaha 2-Stroke Cooling System Marine-Grade Construction 8M6010294. Overview. When you spend enough time on the water, you learn to appreciate the parts that keep your engine running steady-quiet heroes tucked under the cowling, doing their job without asking for attention. A thermostat is one of those parts. The Quicksilver 8M6010294 Thermostat helps Yamaha 2-stroke outboards warm up quickly, hold the right temperature, and stay responsive no matter the conditions. Whether