50 : 1 is the correct fuel mixture
What is the fuel to oil ratio for a mercury 9.9 hp 2 stroke engine?
50/1
50:1
50 to 1
50:1
50:1
50;1
50:1
For the Mercury 9.9 Two Stroke Engine it is 50:1...
Mercury outboards prior to 1966 use a 24:1 fuel to oil ratio.
A 4hp Mercury outboard requires a 50:1 fuel to 2 cycle oil mix.