Re: 72 johnson control
One white wire is connected to the "S" (Starter Solenoid) terminal of the ignition switch, with the other end of it connected to one of the shift switch white wire terminals The other white wire leading from the instrument cable wiring harness would be connected to the remaining white wire shift switch terminal.
Within the shift switch is a safety switch that disengages the electric starter circuit whenever the shift switch is in gear so as to prevent the engine being started when in gear.
To bypass this safety feature (not a good idea), simply connect the white wire leading from the "S" terminal of the ignition switch to the white wire leading from the instrument cable.
(Hydro Electric Shift System Explained)
(J. Reeves)
The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.
You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)
Note: The engine must be running OR have the driveshaft turning by some other means in order for the engine to shift.
In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)
To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.
This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.
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(Toggle Shift Switch Setup For The Hydro Electric Shift Unit)
(J. Reeves)
NOTE (Disclaimer) - The following toggle setup will suffice BUT it is extremely dangerous. Should you use it, you are agreeing to use it at your own risk with myself disavowng any responsibility for its design or use.
Due to the unavailability of the "Push Button" (Evinrude) or "Toggle Type" (Johnson) shift switch that is required for the "Hydro Electric Shift" type lower units that existed between 1968 and 1972, many boaters have asked how they could rig up a toggle switch to perform this shifting function. There may be much better solutions but the following is what I have come up with.
One must keep in mind that wiring a toggle switch in such a manner allows one to accidently shift from forward to reverse at full throttle. This could and probably has resulted in injuries to boaters, not to mention the mechanical damage. Should this or any other problems arise/occur, I am in no way to be held responsible for the toggle switch to shift switch replacement mentioned here.
For the above reason, I strongly suggest that the toggle switch have a hinged hard case cover installed over it so that the toggle can never be thrown/toggled accidentally.
Now, with a single pole double throw toggle switch (or using one side of a double pole double throw toggle switch) installed so the "Green" wire connection is facing up or away from you, make the following connections to the terminals on the back of the toggle switch.
......O <--- Green Wire
......O <--- 12 volt Supply
......O <--- Blue Wire
Now, between the Green wire and Blue wire terminal on the toggle switch, connect a diode capable of handling 12 volts (available at Radio Shack etc). Be sure to install the diode so that the voltage will travel from the Blue wire connection to the Green wire connection only...... and not vice versa!
Now, if you have installed the switch as above, with the toggle pulled all the way back (towards yourself), contact will be made between the 12v supply and the Green connection. This puts the unit in Neutral. The diode prevents any voltage from gaining access to the Blue connection.
Pushing the toggle lever to the middle position results in no voltage being supplied to either wire. This results in the spring loaded clutch shifter dog in the lower unit throwing the unit into forward gear.
Pushing the toggle switch lever all the way to the front position will have the center 12 volt supply connected to the Blue wire connection, and due to the diode, that 12 volt supply will also be supplied to the Green wire. This results in having the unit in reverse gear.
