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1970 Merc 650 ignition switch won't kill engine

J

Joe Baublis

Member
In the process of rebuilding 2 carbs on the merc 650 I detached a few wires. Apparently I put something together wrong. Ignition test was great, and the cleaned carburetors improved the engine performance enormously. But when I turned the key to "off" the engine did not kill.

Anybody know where I can find a wiring diagram for a merc 650?

Or, I have a 6 prong power cord. Two large prongs for the battery. Does anyone know what systems the other 4 prongs connect? One of the 4 wires (green wire) connects a choke button. IMG_1540.jpg
 
haventaclue said:
Someone has replaced the wires,the choke wire should be grey.You will need to determine which each pin/prong is for,this diagram should help. http://www.maxrules.com/oldmercs/Wiring/1966ona/30.gif
Click to expand...

Wow Mr. Clue, that's a great diagram. Thanks. I have a question for you please. The starter solenoid shows 2 wires, yellow and black ground. But which terminal does the yellow wire connect to? One terminal is light steel colored, but the other is darker brass color.

On further inspection is looks like the green wire running up to the choke is connected to a grey wire down by the power harness. It appears that the original grey wire was in very bad condition and it was spliced to a new wire colored green.
 
Yellow to the terminal nearest the tan wire from the solenoid to the starter,the one you can see in the pic.
 

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  • Powerhead Tach wiring.jpg
    Powerhead Tach wiring.jpg
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Hey Mr. Clue,
Thank you very much for the diagram, and for the photo. I was able to remove and replace all the old bad decaying wires. The old 650 started up this morning with key-turn. I launched the boat today and all seems to be fine. Thank you for your assistance.
 
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