Old Johnson Control box

[18Warrior]

I have an old Johnson remote control box, with a black round plug to mate with the engine harness. It looks the same as my yellow plug control box on my 72 50 hp Johnson, but it won't start the motor. Can anyone tell me what year OMC's used the big round black plugs?

 

[racerone]

The yellow plug was used on the 71 and 72 model 50 HP.-----And also the 72 model 65 HP.-----These motors and only those 3 models used the " magflash " electronic ignition.----And also the electric shift.-----Circuit ( yellow plug ) is OPEN to run.----Black plug motors use battery electronic ignition and circuit is CLOSED to run.

 

[18Warrior]

Thanks for the info