1974 Evinrude 40hp ignition

[Matt53]

I recently got a 1974 Evinrude 40hp with no control box. It has a black wiring harness plug and after poking around for a while I figured out what some of the pins do, but I’m still trying to figure out what several of them are for. Starting with the large post on the right that seems to be a ground, under that is the starter trigger, and the choke. On the left hand side this is where I’m confused. When I put 12v to the lower pin I get power to the coils, but I can’t seem to figure out what the top pin is. I’d really like to get it running before I spend the money on the control box, so any help with this wiring confusion would help, Thanks!

 

[racerone]

Stop !!!-----The coils on this motor do not use 12 volts from the battery to make spark.-----And I am working on a 1974 model 40 hp for the grandson.----New pistons and rings / water pump impeller / carburetor kit etc etc.----You may have done damage to points and coils if you applied 12 volts to them.

 

[Matt53]

I saw a wiring diagram that showed keyed 12v going to that post on the connector, but hopefully I didn’t burn anything up. Does yours use a black or a red plug?

 

[racerone]

Black plug.---12 volts is only used to energize the start solenoid and the choke solenoid.----The magneto under the flywheel generates the spark when it turns fast enough.

 

[Matt53]

So that pin in the plug is used to ground the coils to shut the motor off?

 

[racerone]

There are 2 posts on the ignition switch marked " M "-----To run the 2 posts are OPEN.------To stop the motor the 2 M posts are connected.

 

[Matt53]

Ok, that makes sense, thanks for the help. Now I guess it’s time to see if I burnt up the coils