The 1972 model, 125hp Johnson, requires a 50:1 fuel, to 2 cycle oil ratio. This is roughly one pint of oil, to six gallons of fuel.
There are a couple of options... Coil is number one, Or the electronic box......
The spark plug gap for a 2003 Mercury 125hp outboard motor is .040"
I have a 1972 85esl72 Johnson outboard motor and I use a 50:1 ratio.
50:1 is the correct mixture for a 1992 Johnson 60 hp outboard.
50:1
50 to 1
32:1
50-1
50:1
50:1
40:1
50:1