1979 140 hp mercury choke problem

starcraft18

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Joined
Jun 28, 2007
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12
i am working on a 1979 140 hp mercury all the wiring insulation on the motor was cracked and missing i replaced the wires 1 at a time the problem is now when i try to start it the choke doesn't work with the key in the on position
and when you push the choke button. but it does kick in when the engine while the engine is turnnng over has any one ever experienced this problem
i don't if it was working right before or not . can any one direct me to a wiring diagram or tell me which wire is the choke wire coming out of the plug
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,148
Re: 1979 140 hp mercury choke problem

The choke was the grey wire. It runs from the ign accessory pole to the button to the choke solenoid. The ign key must be in the on or start position for it to have voltage. It sounds like you have it wired to the starter solenoid
 

Barnacle_Bill

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Feb 8, 2004
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6,469
Re: 1979 140 hp mercury choke problem

According to my manual its yellow/black. It should go to the "C" position on the switch.
 

starcraft18

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Jun 28, 2007
Messages
12
Re: 1979 140 hp mercury choke problem

I haven't messed with the wires coming from the box to the motor
the wire that goes to the choke solenoid is grey it has power on it when the key is turned all the way in the crank position no power in the accesory position will not work with the choke button
 

Barnacle_Bill

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Feb 8, 2004
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6,469
Re: 1979 140 hp mercury choke problem

I stand corrected, it is gray on that motor. But there should not be 12V on it until you engage the choke.
 

tracterman2

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Jun 13, 2007
Messages
17
Re: 1979 140 hp mercury choke problem

use the diagram and find you a cheap multimeter at walmart or something...I wouldn't do any wiring with out one...put it on DC and either 10 or 40 thats what most cheap multimeters will read that will let you get a good reading with 12 volts and have a buddy push the button in while you touch the prongs of your harness. Once you find the one that gets 12volts when your buddy pushes the choke button you have it. Make sure that wire goes directly to the choke soldnoid. If that checks out take a long wire from the solenoid and touch the postitive on your battery, if it pops out its still good. Diagrams are great but everything can have differences or someone that has piddled with them before, I would check and make sure I'm getting current in the right place at the right time with a multimeter. I just got done rewiring a 1150 with a "newer" quicksilver control box and no harness...everything is hard wired...so I couldn't use a diagram...but with the multimeter it took some time but got everything figured out...hope this helps...:)
 

starcraft18

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Jun 28, 2007
Messages
12
Re: 1979 140 hp mercury choke problem

thanks for all the help guys this is a great site i will let you know what i find out
 
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