The 1957 Johnson FD-11 Owners Manual states quite clearly one quart of oil to six gallons of gas (24:1) is the required fuel mixture for this motor. For ease of mixing smaller amounts of fuel, 1/2 pint of oil per gallon (16:1) is recommended as the oil also came in 1/2 pint containers, not 1/3 pint containers. The 16:1 mix is mandatory in the 3, 5 1/2, and 7 1/2 horse motors and nowhere is 32:1 or any other mix mentioned.
I’m sure OMC allowed some leeway with the 24:1 requirement due to inaccurate measuring by tipsy sailors but for peace of mind, I’d try and stick with the 24:1 mix.
