1973 Mercury 500 control box (key ignition, choke, shift-interrupter, tach connector) wiring questions

[am1590]

Here is the diagram of the wiring.

https://maxrules.com/oldmercs/Wiring/1966ona/26A.jpg

The wire harness connecting to the control box has 7 wires z(black, white, red, yellow, gray, brown, and a color I can only describe as peach or salmon- I am guessing the "tan" on in the diagram?) The original key ignition switch has 5 prongs, a separate 2 prong choke switch. I am having trouble locating these parts. Can a 6 prong push to choke key ignition switch be used instead? Can the tach connector be removed from the system? If the tach connector can be removed do I just dead end the brown wire?
Thanks,
Aaron

 

[Chris1956]

Yu can use a push to choke ign switch. Just connect the grey wire to the choke terminal. The original ign switch needed to provide ign power to one side of the choke button. A push to choke has that wired internally.

The orange or salmon wire is the usual ign killer wire. Not sure why it shows as tan on your diagram. It is grounded when the ign key is turned off.

The brown wire is pulled thru to the tach connector on the MerControl. It does not need to be connected to anything, but don't ground it. If you want to use a modern tachometer, it will need to be connected to one of the yellow/red stator wires, as ones driven off the switchbox are antiques and not widely available.

 

[am1590]

Thank you for the help Chris! I am going to get the parts I need ordered and try to get it put together next week. I'll let you know how it goes.

 

[am1590]

Yu can use a push to choke ign switch. Just connect the grey wire to the choke terminal. The original ign switch needed to provide ign power to one side of the choke button. A push to choke has that wired internally.

The orange or salmon wire is the usual ign killer wire. Not sure why it shows as tan on your diagram. It is grounded when the ign key is turned off.

The brown wire is pulled thru to the tach connector on the MerControl. It does not need to be connected to anything, but don't ground it. If you want to use a modern tachometer, it will need to be connected to one of the yellow/red stator wires, as ones driven off the switchbox are antiques and not widely available.

Just did a test run and it worked perfect. Time to solder it all together. The new switch is a bit longer but it does just barley fit. Thanks again for your help!

 

[am1590]

For anyone else doing this:

Credit John White from JustAnswerBoat:

"Switch Terminal Translation

B = Battery
I = Ignition
S = Start

M = Magneto

C = Choke



Wire Color To Switch Terminal
Red - Connect to B terminal

White - Connect to I terminal (may be more than 1 wire)

Yellow - Connect to S terminal (should be coming from safety neutral switch in control box)

Black - Connect to M terminal (may be more than 1 wire)

Orange or Salmon - Connect to other M terminal"

Gray wire connect to C (Choke) terminal.