A Johnson outboard, model number CD24D is a 1967 model, 6 hp engine.
A Johnson outboard, model 6R-74C, would be a 1974 year model, 6 hp.
I have a 6 hp Johnson seahorse outboard and I was told to run it at 40:1 and have done so for ages and runs fine.
1984 Johnson 6 HP
50:1
A 6 hp Johnson, 1969 on, will run on a ratio of 50:1, or one pint of 2 cycle oil mixed to six gallons fuel.
The 1996 model, 6 hp Johnson outboard, requires a 50:1 ratio, roughly one pint of 2 cycle oil, to six gallons of fuel.
Johnson 6hp spark plug gap
48lbs 27.1kg
according to the clymer manual it is 50 -1
50/1 1 pint oil to 6 gallon of fuel
If it's in really good condition, about $250.