Logo
FULL SITE MENU

1969 Johnson 55ESL69A vacuum switch location

D

Dterry

Contributing Member
Hi

Trying to find the vacuum switch on this engine but can only locate the thermo switch. Should I be seeing wires from the vacuum switch from somewhere visible?

Dan
 
The vacuum switch is located on the starboard side of block about half way down and has wires coming from it. You can find it on a parts breakdown.
 
Last edited:
The vacuum switch has a rubber diaphragm covering it , about 1-1/2" diameter.----------Why are you looking for it ?
 
Thank you for the reply, I'm looking for it because I believe that the previous owner disconnected the vacuum switch because I am not finding any wiring going to it. I was going to post some pics but having trouble loading it.

And I also herd that you are suppose to disconnect the thermo switch and rewire because of choke issue's, is this true?

Dan





racerone said:
The vacuum switch has a rubber diaphragm covering it , about 1-1/2" diameter.----------Why are you looking for it ?
Click to expand...
 
And do you know what the vacuum switch does on that motor ?-----------And are you sure that it is the original block / model year on your motor ?------------Same serial # on the core plug?
 
racerone said:
And do you know what the vacuum switch does on that motor ?-----------And are you sure that it is the original block / model year on your motor ?------------Same serial # on the core plug?
Click to expand...

Not a 100% sure if it is the same original block and I believe the vacuum switch signal's when there is fuel blockage and sounds an alarm?

Dan
 
You are TOTALLY wrong on that assumption.-------The vacuum switch has to do with the electric shift on that motor !!!
 
racerone said:
You are TOTALLY wrong on that assumption.-------The vacuum switch has to do with the electric shift on that motor !!!
Click to expand...

So how is the wiring from the shift solenoids attached to the vacuum switch? Because it looks like in the wiring diagram it runs directly to the plug.

Dan
 
I sometimes ask questions but get no answers to help the poster.--------Perhaps the questions are meaningless or seem like a joke.---Have you found the location where the vacuum switch mounts , yes or no.------Is there a hole open to the crankcase , yes or no.-------Does your motor have the shift diodes , yes or no ?------Have you found the serial # on the block , yes or no ?---The original parts diagram shows the vacuum switch.---------But your motor may have been updated with the diodes.------I am not standing beside YOUR motor so I can not quickly tell you what is going on with it !!!
 
For safety I would add a fuse at the start solenoid for the red wire going to the ignition switch that way you dont light up the harness in case of a internal short in the harness.
 
racerone said:
I sometimes ask questions but get no answers to help the poster.--------Perhaps the questions are meaningless or seem like a joke.---Have you found the location where the vacuum switch mounts , yes or no.------Is there a hole open to the crankcase , yes or no.-------Does your motor have the shift diodes , yes or no ?------Have you found the serial # on the block , yes or no ?---The original parts diagram shows the vacuum switch.---------But your motor may have been updated with the diodes.------I am not standing beside YOUR motor so I can not quickly tell you what is going on with it !!!
Click to expand...

I am not home right now but I will tell you what the model number is and if I see any openings in the crankcase and if there are any diodes when I get home. I appreciate your help even if your questions may seem meaningless or a joke.

Dan
 
racerone said:
Delete.
Click to expand...
Kinna confused here in order to be running at high speed the shift lock in the control keeps you from shifting into neutral at high speeds if the pressure switch always provides power to the green wire when the engine is running (has vacuum) how can it shift into forward?
 
Time to investigate and learn this simple stuff.------The vacuum switch holds it in nuetral when the key is turned off.----Allows it to safely slip into gear when vacuum is lost.
 
Almost afraid to jump into this discussion, but to back up and explain the correct answers here goes. Without the vacuum switch, the instant you turned the ignition key off, power was lost to the shift switch. So...motor is idling in neutral. You turn the key off and power is lost to the shift switch--the power that was holding it in neutral. Without power, the shift defaults to forward. Summing up, when you turn the key off, it jumps into forward gear with a clunk. Harmless, but annoying and disturbing. The vacuum switch fixes all that by continuing to send power to the shift switch until the engine coasts to a stop. Then it lets it jump into forward gear---AFTER it has stopped running, so you don't notice it. Yes, the following year, the system was changed, feeding power to the shift switch from the alternator (extra diodes) until it coasts to a stop.

Clear as mud?
 
As for the thermo switch: Yes, there was a mod on that. It was for people that were having problems with over choking under certain conditions. It is not a "supposed to", but a fix for those having the problem. In other words, don't worry about it unless....
 
Ok it makes sense now If it is in reverse it stays in reverse until the engine stops same as if its in neutral. In forward gear it dont matter as it already is in gear.
 
***********************************
(Vacuum Switch - 1969 55hp Evinrude/Johnson)

Keeping it simple........ The vacuum switch keeps 12v applied to the Neutral solenoid in the lower unit for a few seconds when you turn the key to the OFF position.

If not for that feature, when you turn the key OFF, the lower unit would slam into forward gear, causing the boat to jump ahead somewhat.

**************************************
(Temperature Actuated Choke Solenoid Conversion)
(J. Reeves)


Various OMC engines that were manufactured in the later 1960s thru the early 1970s, for example the 1969 55hp Evinrude/Johnson incorporated a dual stage choke solenoid...... easy to identify as they have two wires leading to the solenoid, one purple/white, one purple/yellow.

The purple/yellow is attached at the engine wiring terminal strip to another purple/yellow wire that led to a heat sensor. The initial stage, with the key ON, (purple/yellow), when cold, would keep the choke pulled in half way until the engine warmed up, at which time it would release and open the choke butterfly.

The second stage (purple/white) is attached to another purple/white wire at the engine terminal strip which leads to the choke switch. When the switch was engaged, the choke closed etc.

The problem with this setup is that as the engine got older, the thermostat acted up, water pump became weak, whatever, the heat sensor failed to operate properly and the choke would not release from that half closed position. This would cause the engine to run in a rich fuel mixture condition (flooding, loading up).

The cure to this problem, via a service bulletin from OMC was to remove the solenoid purple/yellow wire from its original location and connect both of the solenoid wires (purple/yellow & purple/white) to the engine wiring harness purple/white wire at the engine terminal strip.

The above change would allow both solenoid wires to be energized when the choke switch is engaged, pulling the choke butterfly in firmly..... and only when the choke switch is engaged.
 
I have a 1968 johnson outboard 100hp electramatic with a green and red wire coming from the vacuum switch, does anybody know what these are wired to? I've bought a couple different service manuals, spent countless hours searching the internet, and even talking to my local marine mechanics and all I get is it's function. I understand what it does but can't find anywhere what it's wired to?
 
Do really understand it's function? It is NOT the same function as the 55hp in this thread. On the 100hp it delays the 12V input to the pulse pack until the starter is cranking the engine (providing vacuum). Reason is, the original setup provided a spark to a cylinder when the key was turned on. If conditions were right in the cylinder, the motor might start running without running the starter motor, possibly running over something or somebody. Replacement pulse packs did not do this, so the vacuum switch was removed as un-needed.

It connected between the 10-way plug and pulse pack.

Now let's put this old thread back into the archives.
 
Dterry said:
So how is the wiring from the shift solenoids attached to the vacuum switch? Because it looks like in the wiring diagram it runs directly to the plug. Dan
Click to expand...

Dan... If memory serves me properly (quite a ways back ya'know), the purpose of that vacuum switch on that model was to keep voltage applied to the neutral solenoid until the engine shut down completely... otherwise in starting or just as the engine is shut down (since the default is forward due to a spring loaded clutch dog), the boat would jump forward. If my memory is proper, that could take your head off if you were just pulled up to a neck high dock.
 
Damn... did it again Gator. I had already entered that spiel a year ago (above) just wasn't paying attention.... two years listing, two different engines... might as well stuck in a antique Scott Atwater while we were at it.
 
Last edited:
Back
Top