Tweet
I wanted to know how hot my 40HP Yamaha should run under normal conditions so I called Yamaha direct and asked them.Here is what they said idling at the dock my motor should run from 140 to 145 degrees up on a plane at high speed around 160 degrees.The motor has over heat sensors on the head that are set to go off around 199 to 200 degrees.I purchased an infrared thermometer to check my running temps and I made sure my over heat sensors and warning buzzer worked.This weekend after Sandy passes I will check it out on the lake at the dock to make sure my motor is running at its correct temp.