1975 40hp Wiring

[MidnightSpeedKC]

Heck of a first post, eh?


Ok, figured out most of the wires on this thing, just need to figure out how to wire them into my Key ignition.

I have three posts on the back of the ignition.

1 - BAT - 12v Supply (red w/purple stripe)
1 - ST - Start Wire (yellow wire)
1 - IGN -

I can get the motor to start this way, but I can not get it to shut off unless I touch the Solid Blue wire with the Blue w/ white stripe wire.

How do I wire these two wires to get this to shut off when I turn the key to off????


I just picked up a 1975 40hp Johnson. The wiring was cut from the turn key ignition up inside the boat and I cant figure out what a couple wires are.

I know:

Yellow = Start
Green = Electric Choke
Red w/ purple stripe = 12v Power Supply
Blue w/ white stripe =
Blue =



This motor is going on my first boat which is a 1968 Glass Magic. It's totally vintage and I love it!

 

[F_R]

Re: 1975 40hp Wiring

Heck of a first post, eh?



I just picked up a 1975 40hp Johnson. The wiring was cut from the ignition and I cant figure out what three wires are.

I know:

Yellow = Start
Green = Electric Choke

There are three other wires...I believe one of them is Red, another is Purple, and not sure ... maybe Grey?

I need to know what the other three do so I can finish wiring this motor!



This motor is going on my first boat which is a 1968 Glass Magic. It's totally vintage and I love it!

What you have does not match the diagram. It shows:

Purple jumper from ign Acc to choke switch.
White is start
Blue and blue/white stripe to ign "M" terminals (might be "M" and "G")
Red/purple stripe 12V supply
Purple/white stripe is electric choke.

 

[gazza2007au]

Re: 1975 40hp Wiring

gray is showing as tach wire on various models purple is showing ignition on a few models aswell red is more than likely power to or from the battery

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

What you have does not match the diagram. It shows:

Purple jumper from ign Acc to choke switch.
White is start
Blue and blue/white stripe to ign "M" terminals (might be "M" and "G")
Red/purple stripe 12V supply
Purple/white stripe is electric choke.

I'm gunna check these out. The colors on these wires are so incredibly faded, that I'm going to try to peel the wiring harness connector back to expose the wires a little more.

Thank you guys for the help!


I also forgot to mention that this is a Manual Shift motor.

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

gray is showing as tach wire on various models purple is showing ignition on a few models aswell red is more than likely power to or from the battery

Thank You! I'll check these out as well!

 

[F_R]

Re: 1975 40hp Wiring

Thank You! I'll check these out as well!

If it actually has a tach wire, that is fine. The diagram that I have doesn't show one. As I said, Purple feeds the choke switch and is "hot" when the ignition is on. The ignition system itself is magneto powered and does not get an "ignition" feed. The two blue wires turn it off.

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

ugh...I'm frustrated.

I've got a turn key starter thing (Johnson) from a 70's model 55hp, which I'm using for my 1975 40hp Johnson motor.

I put the Red w/ Purple Stripe on the BAT post
I put the Yellow on the ST post
I put the Blue w/ white stripe on the IGN post.
I have the Solid Blue run down to the Ground (-) battery post

I got the motor to turn over when I turn the key to start, but everytime when I let the key spring/go back into the 'on' position, the fuse blows. I'm using a 32v fuse.

What am I doing wrong here?!?!?!!?

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

anyone?!?

Bueller? Bueller?

 

[F_R]

Re: 1975 40hp Wiring

ugh...I'm frustrated.

I've got a turn key starter thing (Johnson) from a 70's model 55hp, which I'm using for my 1975 40hp Johnson motor.

I put the Red w/ Purple Stripe on the BAT post
I put the Yellow on the ST post
I put the Blue w/ white stripe on the IGN post.
I have the Solid Blue run down to the Ground (-) battery post

I got the motor to turn over when I turn the key to start, but everytime when I let the key spring/go back into the 'on' position, the fuse blows. I'm using a 32v fuse.

What am I doing wrong here?!?!?!!?

The very first thing you have to do is get the correct igniton switch. That is what is wrong. You have a switch for battery ignition and your motor is magneto igniton. The correct switch will have two "M" terminals (or an "M" and a "G") The two blue wires go to those two terminals, and the switch electrically connects them together in the "off" position to stop the engine. What you are doing now is feeding 12V to one of the magneto coils---that will very likely destroy the coil if it hasn't already.

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

The very first thing you have to do is get the correct igniton switch. That is what is wrong. You have a switch for battery ignition and your motor is magneto igniton. The correct switch will have two "M" terminals (or an "M" and a "G") The two blue wires go to those two terminals, and the switch electrically connects them together in the "off" position to stop the engine. What you are doing now is feeding 12V to one of the magneto coils---that will very likely destroy the coil if it hasn't already.

That's gotta be it! The key switch is from a 55hp Johnson, vs. my 40hp.

I dont think I have destroyed the coils yet, the motor still runs, haha.


You're so incredibly helpful F R

Thanks a bunch!

 

[MidnightSpeedKC]

Re: 1975 40hp Wiring

just ordered a new ignition!