1970 40hp Johnson Electric Shift Questions, long read

possom813

Seaman
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Jun 22, 2010
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I recently traded for a 1970 Johnson 40hp electric(selectric) shift motor.

The motor fires up and runs well.

The model number is 40es 70a

Serial Number J3295244

I'm having issues with the shift control. Not really issues I guess, just questions.

I've checked the resistance on both shift solenoids and on one meter they are both 8.0-8.1 on the other meter they are both 9.1-9.3. I don't have a real expensive meter, just the low end CenTech and I forget the other brand. Both cost less than 20 dollars.

I figure the solenoids are still good. I don't think they would both go out at the same time and have the same resistance.

I read somewhere on the forum to apply 12v to the shift wires coming from the lower unit and try to spin the prop by hand.

With no power applied, the prop spins freely.

With 12 volts applied on the first wire, the prop locks up when spinning counterclockwise

With 12 volts applied on the second wire, the prop locks up when spinning clockwise

Going from the selector switch/throttle control to check the voltage coming from the leads that plug into the shift solenoid wires, in neutral I get no power, in forward I get 12v on one wire and in reverse I get 12v on the other wire.

Which wire plugs in where? Does the wire receiving 12v in reverse plug into the wire that locks the propeller spinning clockwise, or the wire that locks the prop spinning counterclockwise?

Also, we had to wire in a new universal ignition switch. We went with everything that we could find and used the new(automotive) switch strictly as a starting switch. It's wired to the battery, the solenoid, and the shifter for the electric shift.

The magneto wires were separated and put onto on/off toggle switches with a common ground. That's the best we could figure. In theory, with both toggle switches on, the magneto should work as it was with the factory ignition switch and turn both switches off and the key off and the engine should die.

If I'm wrong on this, someone please correct me before I injure myself:facepalm:
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: 1970 40hp Johnson Electric Shift Questions, long read

Your solenoid wiring and readings seems to be correct. Just make sure at no time is there voltage on both shift wires at the same time.
You do not need two toggle switches for the kill switch. You just need to wire one switch such that the two magneto wires are connected together for kill and open for running. No need to ground them.
 

possom813

Seaman
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Jun 22, 2010
Messages
67
Re: 1970 40hp Johnson Electric Shift Questions, long read

Which way do the shift solenoid wires hook up for forward and reverse? Which wire should have voltage in which gear?
 

royal0014

Master Chief Petty Officer
Joined
May 6, 2010
Messages
874
Re: 1970 40hp Johnson Electric Shift Questions, long read

Coils are fine. Green is forward wire (green for go) Blue is the reverse wire. Use a three-way, center off toggle.

DON"T use an automotive key switch, you'll blow the coils. Pony up for a MARINE switch, save 'ya alot of heartache!

Use the search feature here for a wiring diagram. It's out there ;)

Oh, and get the factory manuel......



<<)))(((>>
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1970 40hp Johnson Electric Shift Questions, long read

Your statement: "With 12 volts applied on the first wire, the prop locks up when spinning counterclockwise."

This wire would be forward gear.
 

possom813

Seaman
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Jun 22, 2010
Messages
67
Re: 1970 40hp Johnson Electric Shift Questions, long read

Thank you sir, that's what I needed to know.

As for the auto switch, it's wired in, but not to the magneto or to anything other than the solenoid and starter. It's just there for cranking and the kill switch is wired into a toggle.
 

possom813

Seaman
Joined
Jun 22, 2010
Messages
67
Re: 1970 40hp Johnson Electric Shift Questions, long read

Thanks for the help, it's hard-wired and plumbed in and almost ready for the water. Luckily, the electric controls work 'almost' exactly as they're supposed to, just wish the friction nut wasn't missing, no cruise control.
 
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