1972 40hp johnson ignition wiring help

[ccarpen4753]

I have a 1972 40hp johnson and was wondering if you could help me as well. I need to know how to wire it to the ignition switch. I have a six pole switch, came from my 25hp johnson. Any help would be greatly appreciated. I checked the stickies at the top of the forum and mine wasnt listed.Here is my wiring and motor info:

1972 40hp Johnson model#40EL-72E

Wire colors from motor are: Red (larger gauge wire) Black (larger gauge wire)

Yellow with red stripe Blue with white stripe Blue Tan or Brown Purple Green Grey

6 pole switch labeled:
B,A,M,C,S,M

 

[Joe Reeves]

Re: 1972 40hp johnson ignition wiring help

You've got one long line of colors typed in that is confusing as follows:

"Yellow with red stripe Blue with white stripe Blue Tan or Brown Purple Green Grey"

Separate the colors on individual lines so that we know exactly what those colors are.

Are you sure about that model number? It may be my memory but I don't recall a 1972 40hp having a Yellow/Red Stripe wire or a Blue/White Stripe wire.

 

[ccarpen4753]

Re: 1972 40hp johnson ignition wiring help

1972 40hp Johnson model#40EL-72E

Wire colors from motor are: Red (larger gauge wire) Black (larger gauge wire)

Yellow with red stripe
Blue with white stripe
Blue
Tan or
Brown
Purple
Green
Grey

6 pole switch labeled:
B,A,M,C,S,M

The wiring looks newer, like an aftermarket wiring harness. Well basically i need to know which wires to hook up to get it started, i can probably figure out the accessory wires, i just need the main ones, assuming the larger red and black wires.

 

[tx1961whaler]

Re: 1972 40hp johnson ignition wiring help

B=Battery--> Fat Red Wire
A=Accessory --> 12 Volts on this terminal when key is on
M=Magneto--> Goes to one of the wires coming out from under the flywheel (kill wire)
M=Magneto--> Goes to the other kill wire, which is probably hooked up to the cut-out switch on the side of the motor.
C=Choke--> Goes to electric choke solenoid
S=Start--> Goes to starter solenoid

 

[cocotower]

Re: 1972 40hp johnson ignition wiring help

Concerning the electric choke wiring... how does this system work? Do you press inward on the key to cause the choke solenoid to close the choke valve? I use the manual choke lever at this time. On my motor I cold crank with the choke closed but then it farts and dies... I then open the choke and try again and she cranks. This tells me that the second or third time I crank I don't need to activate the electric choke. There's a switch on my panel that was hooked to the electric choke. I'm assuming that the previous owner had it wired so that if the switch was On that during the cranking procedure (without having to press inward on the key) it activated the choke while the starter was turning. So why not just wire it to the Starter prong on the ignition?

I don't want to burn out the expensive electric choke solenoid.

 

[Joe Reeves]

Re: 1972 40hp johnson ignition wiring help

Yes, pushing the key in supplies 12 volts to the "C" terminal of the ignition switch. Whatever wire is attached to the choke solenoid should be connected to that "C" terminal.

 

[F_R]

Re: 1972 40hp johnson ignition wiring help

As originally equipped from the factory, the ignition switch was not a push-to-choke uint. It had a toggle switch next to the ignition switch. Turning the key on supplies voltage via the "A" terminal to the choke toggle. Holding the choke toggle up sent the voltage back to the solenoid on the carburetor, slosing the choke shutter. The choke wire USUALLY was a purple with white stripe. The wire between the "A" terminal and choke toggle switch USUALLY was purple.

Offhand, I'd say the blue and blue with white stripe are the kill wires going to the "M" trminals, but they USUALLY are black. You have a strange motor.

The start wire from the "S" terminal to the starting solenoid USUALLY is white.

Grey probably is a tachometer ground Not connected if no tach.

Brown probably is a generator wire---if it has a generator kit. Otherwise, not connected.