E-4A Mag Question

F-Dean · Aug 27, 2012

What is the use of the pointed screw on the side of an E-4A Mag?

It looks like a permanent grond-out or a ground in case the coil produces too hot a spark.

If it does have a use, how do I set it?

Nebraska Kirk · Aug 27, 2012

That is the spark safety gap, turn the screw in tight, that is all you have to do.

When the magneto is spinning and producing spark, that spark WANTS to find a ground. If it is not hooked up to spark plugs, then the high voltage spark will find the path of least resistance and could very well short out through the coil insulation if the safety gap is not there. This is not desired because when the insulation fails then the coil fails. If you take the cap off the magneto and spin it by hand you will see the spark jump from the collector ring to that pointed screw. Kind of like the pressure relief valve in a hydraulic system.

Tom Fleming · Aug 28, 2012

Yup, what he said!

F-Dean · Aug 29, 2012

How do I adjust the screw? If I gap the plugs at 0.030 and this is set at 0.025, won't it spark instead of the plugs?

Tom Fleming · Aug 29, 2012

that screw is not adjustable. Run it in snug, and you are good to go.

Nebraska Kirk · Aug 29, 2012

(quoted from post at 14:05:29 08/29/12) How do I adjust the screw? If I gap the plugs at 0.030 and this is set at 0.025, won't it spark instead of the plugs?

The factory spark safety gap is a LOT wider than .030, it is at LEAST .250" Take the cap off the mag and you can look inside and see how far the point of the screw is from the collector ring.

You do not adjust the screw, as I said in my previous post: "turn the screw in tight, that is all you have to do."

E-4A Mag Question

F-Dean

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Nebraska Kirk

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Tom Fleming

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F-Dean

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Tom Fleming

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Nebraska Kirk

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