Questions about choke solenoid

TAC_Double

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Sep 23, 2006
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93
When I bought this engine, the choke solenoid was disconnected. I have been trying to get it working again. What I found was that the plunger spring was missing, and they had disconnected the ground to it.

I have replaced the spring and tested the solenoid as per the manual. When I turn on the key, the plunger goes down in the solenoid and never comes back out. I am not activating the switch for it... it just does it. I am I missing something here? or does it have a mind of it's own. The switch seems to do nothing to it.

1975 85hp Model 85933
 

darrklim2

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Re: Questions about choke solenoid

Maybe that's why it was disconnected? It might be bad?
 

tashasdaddy

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Re: Questions about choke solenoid

something is wrong in the switch. what year is it. the one where you push the key in or the ones with the separate lever for the choke. choke switch may be shorted.
 

TAC_Double

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Re: Questions about choke solenoid

It's a 75.... It has a seperate switch under the ignition. I was leaning towards the switch, but I wanted to get some other thoughts in case I was missing something....
 

ezeke

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Sep 19, 2003
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12,532
Re: Questions about choke solenoid

Look on the top of the engine and see if there is a pair of wires running out of a recessed point adjacent to the lifting eye.

If the wires are there, it is a variable resistor temperature sensor which was supposed to control part of the choke solenoid.

Most of them were disconnected by service departments many years ago, but people have wiring diagrams and service manuals, so they hook 'em up again.

If you have one post back here.
 

TAC_Double

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Re: Questions about choke solenoid

ezeke,

I did find a sensor that is right behind the power pack. The wiring is next to the lift eye, runs behind it and ends at the terminal strip next to the flywheel.

The wiring is purple, like the choke and terminates on the terminal strip right be the ones I think go to the choke solenoid.
 

Dhadley

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Feb 4, 2001
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16,978
Re: Questions about choke solenoid

There was a service bulletin out years ago saying to disconnect the wires to the heat sensor. The theory was that it would act as an automatic "half choke" on a cool motor when a full choke was not needed. Sounds good in theory but really wasn't needed. Whether that's the cause of the problem or not it's OK to do away with the wires.
 

TAC_Double

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Sep 23, 2006
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Re: Questions about choke solenoid

I will disconnect and see if that helps.

Thanks for your help everyone!
 

ezeke

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Sep 19, 2003
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Re: Questions about choke solenoid

I think the service bulletin covers the issue. You may want a copy of a part of the wiring diagram so I will attempt to get that.

The idea is to get the full function of the choke solenoid to the switch on the control and not let the sensor do anything because it never worked right for the most part.
 

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TAC_Double

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Messages
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Re: Questions about choke solenoid

Ok, so I removed the wiring to the thermo switch.

I have moved the purple/yellow wire from 4 to 1. It says I should add a jumper between 1 and 2.. The other purple wire for the solenoid is on 2 with a brown/white wire.

Should I still add the jumper between 1 and 2 or could I just put the purple/yellow on #2?
 
Last edited:

ezeke

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Sep 19, 2003
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Re: Questions about choke solenoid

That should do it, the original solenoid had two circuits, so they wanted all the power for both to come from the control switch after the change:
 

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  • Rewire 1973 & 1974 Choke.JPG
    Rewire 1973 & 1974 Choke.JPG
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TAC_Double

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Messages
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Re: Questions about choke solenoid

Ok, this choke switch is now working as it should. Still having troubles with the solenoid plunger sticking down. The plunger is a little rusty, going to try and clean it up and see if it works.

Thanks for all of the help everyone!
 

Dhadley

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Re: Questions about choke solenoid

Assuming the return spring is still there, and is the correct one, the plunger may just require some cleaning.
 

tashasdaddy

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Re: Questions about choke solenoid

clean it up and some 3 in 1 oil.
 

ezeke

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Sep 19, 2003
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Re: Questions about choke solenoid

Never oil the plunger on the choke solenoid. It should be bone dry all of the time. It is supposed to be stainless steel. If it is dirty or oily, clean the core and the plunger. See page 3-9 in your service manual - "Automatic Choke".

Adjust the choke solenoid by moving the whole unit up and down in small increments, not by stretching or cutting the spring.
 

TAC_Double

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Sep 23, 2006
Messages
93
Re: Questions about choke solenoid

Well, I cleaned the plunger and It is working great. The switch on the control is working now, and I am a very happy guy!


Thank you all for your help!
 
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