1972 100 hp Evinrude- Running, but problem with Hydro electric shift

dstom

Seaman Apprentice
Joined
Nov 22, 2010
Messages
36
YEAH! I got this old boy ('72 100 hp Evinrude) running!!

I noticed when it was idling, that the prop seemed to be spinning rather fast. I know the shift switch in the Johnson Hydro-electrtic remote control was in neutral, because if it was not, the current to the solenoid would be interrupted. I am assuming the prop spin is probably due to the old (10 + yrs) fluid in the lower unit which was going to be changed anyway.

However, in double checking everything before reassembling the remote control, I noticed that the shift switch does not spring back to neutral when the throttle lever is moved to neutral. In other words, it does not return to the indent on the base of the throttle lever. I know I can get a replacement switch, but $300 is above my budget, so I am thinking of a work around. Why wouldn't a single pole, double throw switch, mounted to the dash, work?

Also, I assume there might be other posts/ threads on this topic. How do I find them?

Thanks for all your help (and encouragement)
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1972 100 hp Evinrude- Running, but problem with Hydro electric shift

(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 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.
 
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