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Ski213

Quick electrical system question

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97 Johnson 225. Having an intermittent power loss to gauges issue. I think it's in the ignition switch. Connections good, grounds good as well. My question is, with this type of ignition system, once the outboard starts it will run with zero voltage from the ignition correct?  If I understand correctly turning the engine off is a product of grounding the ignition/power pack rather than removing 12v. Just looking for confirmation on that. It seems like the switch gets 12v to everything when turned to on on the way to start, then when it comes back to on it loses that connection occasionally. Fairly new switch but I'm thinking it has to be it. Any thoughts are appreciated. 

Adam 

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Yes, the CDI system provides all ignition voltage and runs the motors.  The cranking battery is providing power to the starter to spin it.  There timer base generates the initial ignition voltage for each cylinder as the flywheel spins and sends that to the power pack.  The power back amplifies that voltage to approx. 275 peak volts and sends that to the coil, The coil increases it again to fire the plug.   The ignition switch is doing nothing but ground out two wires from the power so it can't provide and ignition voltage to the coil.  If something happens that you can't ground those two wires, you can't turn the motor off without pulling plug wires or choking it down or cutting the gas off to it. 

The accessory side of the ignition switch is only rated for about 7 amps so normally, nothing is hooked to it other than the gauges.  If there's anything else being power off the key switch, I would take it off and run it through the power switch on the boat. 

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Thanks once again for the solid info Way2slow. The previous owner made some wiring changes but it seems like the only things tied to the switch are gauge power in the accessory position so hopefully I'm just looking at a mechanical problem with the ignition switch. It has a "tricky" feel to it when you turn it  just to on. Wants to jump back close to off. Like a detent ball or something isn't working properly. Doesn't fall back far enough to kill the engine but far enough to break contact for the gauges maybe. 

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There are a few different version of the switch, so if you order a new one, make sure you get the right one.  I just had to buy a new one for mine.  The flat wouldn't hold it and it kept wanting to turn all the way around and I broke the threaded section off, over tightening the nut holding it in.  About $35 bucks for that dumb move.

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On June 12, 2016 at 11:32 PM, Way2slow said:

There are a few different version of the switch, so if you order a new one, make sure you get the right one.  I just had to buy a new one for mine.  The flat wouldn't hold it and it kept wanting to turn all the way around and I broke the threaded section off, over tightening the nut holding it in.  About $35 bucks for that dumb move.

I have that same problem with both my old one and the newer one. It'll hold for a minute but then loosens back up. Thought about trying to use some of that 3m weatherstrip adhesive as a thread locker on the switch threads. I've used it in the past in place of blue loctite. It was different materials and different application but it worked pretty well. 

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