Home › Forum › Ask A Member › 1969 Johnson 25R69D › Re: 1969 Johnson 25R69D
OMC motors in the mid-eighties used the 100:1 mix for a short time but it just about put OMC into bankruptcy repairing motors still on warranty. You can throw that mix out the window. Originally, your motor used 50:1 but running it on a little bit richer mix wouldn’t hurt anything and would probably help to extend it’s lifespan.
The thermostat must be working if the water coming out of the idle relief is quite warm. The only way to tell for sure if the motor is at its correct operating temperature is to measure it with an infrared thermometer or special heat sticks. A cheap thermometer can be found online or at stores like Harbour Freight. A fresh impeller or water pump kit always gives peace of mind and the thermostat should be checked or replaced especially if the motor has been used in salt water.