What is the ratio of gas to oil in a 1985 mercury 200 hp black max outboard?

I run my 150hp Mercury V6 on 50:1 pre-mix (fuel to oil) this has been working fine for the last 7yrs! Your engine will be the same if you wish to pre-mix. This equates to 0.5 liters of oil in 25liters of fuel or 0.8pints in 5 gallons. This is very a very common practice where I live, as the Mercury engines are prone to thermostats corroding, then overheating which causes the oil pump drive to shear, loss of lubrication and then seizing!