it is recommended for all fuel oil mix to be 50:1
40:1 ratio
A 175hp Mercury outboard requires a 50:1 fuel to oil ratio.
50:1
The 1996 model, 15 hp Mercury outboard requires a 50:1 ratio, one pint of 2 cycle oil, to six gallons of fuel.
Mercury outboards prior to 1966 use a 24:1 fuel to oil ratio.
The fuel oil ratio for a 140 hp Mariner outboard motor is 50:1. Mariner is a brand of the Mercury Marine company.
50:1
The fuel to oil ratio for a 1984 model, 50 hp Mercury outboard is 50:1. This is roughly one pint of 2 cycle oil, to six gallons of fuel.
The 1979 - 1980 model, 115 hp Mercury outboard, requires a 50:1 ratio. One pint of 2 cycle oil, to six gallons of fuel.
The 1975 model, 7.5 hp Mercury outboard, requires a 50:1 ratio, roughly one pint of 2 cycle oil, to six gallons of fuel.
Merc's use a 50:1 mix
The 120 hp, Force / Mercury outboard, requires a 50:1 ratio, one pint of 2 cycle oil to six gallons of fuel.