Help wiring 1979 70hp merc 12 plug harness to old-school 7 wire controls

[Tmacular]

here's a few pics but I can't find in my book what colors these are for on the old unit. It has 7 total. My plug in for my 79 merc70hp has 12 but the control box im replacing has 7. Refer to pics. I have a new key and ignition that matches the wires perfectly just don't know how to hook it to these controls

 

[Tmacular]

Scratch the above. I ran the 12 wire to a new ignition and key. The new key came color coded perfectly for my 12 wires. However I now have 1 issue. I ran my ignition wire through my neutral safety switch and then to ignition but my engine will still start in forward. Am I wrong on the wire choice or is my neutral safety bad?

 

[Chris1956]

The neutral safety switch should use the starter solenoid wire. You do not want the motor to crank if not in neutral.

 

[Tmacular]

Hey Chris, do i want both the ignition wire and the starter on it or just the starter?

Cheers

 

[GA_Boater]

Neutral safety switch stops starter from cranking the motor in gear. So only the starter circuit is wired through the switch.

Ignition is electrically separate from starter.

 

[Tmacular]

Perfect Chris that fixed it! I'm back in action. I know this isn't relevant to this specific post but my electric choke plunger fell out of the solenoid and I'm not sure if something broke or how this goes back in this is what I have. I'm sorry for the close up I can't figure out how to get my photos from phone under 2mb without zooming and screensshotting. The tip of thr plastic looks like a flathead

 

[Tmacular]

Also thank you for being there for every question I have. I'm learning and slowly liking the way these Mercury's are setup. But without help from guys like yourself id be lost! Thank you thank you!

 

[Chris1956]

The choke solenoid plunger is held in by magnetism. Just slip it back in, and it should stay.

One more thing. Your ignition is run by the stator and switchbox. Battery voltage is not involved. The spark is killed by grounding the orange (or salmon) colored wire.

 

[Tmacular]

Awesome dude I appreciate everything. I got her purring like a kitten now. I'm trying to find out which wire is for a temp sensor on that 12 point. My believe someone changed the harness out on this motor bc the book seems to think an 8 wire plug is correct for my motor. So I know grey is tach, but which is temp? Thanks

 

[Chris1956]

Check the cylinder head for a temp sensor wire. Not sure you have one, but if you do, it will be obvious and likely brown.