Won't turn off when the key is turned off?

supreme

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Sep 14, 2008
Messages
29
I have a 40 hp 74 model 40455s, it won't turn off when I turn the key off. Is the timing to advanced and how do I change that if be? When I turn the key it sounds like it starts to run on one cylinder. but won't kill the motor. Thanks for all the help!
 

asdasc

Senior Chief Petty Officer
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Aug 28, 2008
Messages
680
Re: Won't turn off when the key is turned off?

My guess is that the key is only the starter, and not needed to run. Look for a kill switch or just choke it to stop.
 

supreme

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Messages
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Re: Won't turn off when the key is turned off?

The ignition is hooked up with the mag. wire going to it. When the switch is off it shorts out the mag like a kill switch. I checked all the connections and ground everything looks good. The switch is new as well.
 

F_R

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Jul 7, 2006
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28,226
Re: Won't turn off when the key is turned off?

Something is wrong with the wiring hookup or else you have the wrong ignition switch.

There should be two black wires running between the magneto and ignition switch. The switch electrically connects those two wires together in the "off" position. If the wires aren't there, or if they are broken, it won't shut off. One of those two black wires also goes to the vacuum cut-out switch on the side of the powerhead.

If you have the wrong switch, it won't connect the two black wires in the "off" position. The correct switch has two "M" terminals, or one "M" and one "G". Same thing inside. The two black wires go to those two terminals. Note that the "G" terminal cannot be grounded in addition to the mag wire.
 

supreme

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Re: Won't turn off when the key is turned off?

So, when the switch turns off it is shorting the two mag wire out? Are they shorting each other out?. Many Thanks!
 

F_R

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28,226
Re: Won't turn off when the key is turned off?

Yes, connecting the two shorts out the mag, killing the spark. There are two sets of breaker points, and one of the two wires leads to each. So, when one set of points is going about the business of doing it's thing, the other set is closed. Connect a wire to the set that is doing it's thing and run it through a switch and back to the closed set and it effectivly connects the active set to ground and it can't do it's thing.
 

supreme

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Re: Won't turn off when the key is turned off?

Many Thanks, F_R , it works, thank you!
 
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