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JCS

Bad Coil or motor?

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JCS
Got 7119 and while idling it seems like it is missing but when running it seems o.k. Uncle says the 1/2 of coil is bad and one wire isnt firing the plug. Since coil has two plug wires coming out I sorta believe him but wanted to check with you guys. I plan on starting and pulling the plug wires to see if spark also.,

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HubbardRA
If the coil itself is bad, neither wire will fire. If one wire is grounded, or one spark plug is grounded by fouling, the other will continue firing. If one plug goes open or a wire breaks, neither plug will fire. As you can see in the picture below, the only difference is that the output coil of a single cylinder unit has one wire internally case grounded, while both ends of the coil go to plugs in the double coil.

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powerking_one
Rod, Are you sure that is how the KT-19's coil is configured? It doesn't make a lot of electrical "sense". I would think one side of the secondary would be grounded and the other would "Y" off to both spark plugs. Alternately, I'd think the secondary would be center tapped to ground and then each plug would share 1/2 the windings. I haven't dealt with the KT series very much. Tom(PK)

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HubbardRA
Tom, This is the way the Onan coils and nearly every motorcycle coil that I've seen are wired. Remember that a plug is really ground with a spark gap. The only ones that I have worked on that have separate or divided coils, also have separate triggers or points. We tried to use two separate coils on a single set of points once. It ran but not smoothly. Problem is that the two coils have different resistances. Lowest resistance pulls the most current and takes the most charge. The double coils I showed above always fire the same spark through both plugs. Only the plugs themselves can make a difference.

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