Thermostat (60°C/140°F) – Fits Yamaha 4-Stroke 2.5-100 HP (Replaces 66M-12411-01, 6G8-12411-00) family-yamaha-25elrq or the engine not shutting

or the engine not shutting off when the key is turned to the OFF position

or a noticeable reduction in overall engine performance

Johnson/Evinrude part numbers 0778317

Some installations require a thin bead of marine-grade silicone sealant on both sides of the gasket

If you are not experienced with outboard engine internal components

Thermostat (60°C/140°F) – Fits Yamaha 4-Stroke 2.5-100 HP (Replaces 66M-12411-01, 6G8-12411-00) family-yamaha-25elrq or the engine not shuttingThermostat (60C 140F) Fits Yamaha 4 Stroke 2. 5 100 HP & Honda 8 225 HP This thermostat is engineered to maintain optimal engine temperature for a wide range of Yamaha and Honda 4 stroke outboard motors. It ensures your engine operates within its ideal temperature range, preventing both overheating and overcooling to maximize performance and longevity. This component is a direct replacement for multiple OEM part numbers, fitting Yamaha models from 2.