confirming magneto wiring

gfr56md · #1 11-05-2009, 07:26 AM

Greetings
I am wiring 1 magneto (other ignition is Electronic). I want to know what (if any) way I can confirm proper wiring of mag to the switch with an ohm meter.
Regards Jerry

Mel · #2 11-05-2009, 07:32 AM

First, you must disconnect the mag.
Measure from the "P" lead to ground. With the switch in the "MAG ON" position, you should show an open circuit to ground. With the switch in the "MAG OFF" position, you should show a short from P-lead to ground.

gfr56md · #3 11-05-2009, 08:20 AM

Thanks for quick response.

I must have something wired incorrectly as I am getting zero resistance between the ground stud and the "p" lead stud at the mag. I have measured with the shielded portion of wire connected to the switch and disconnected from the switch with the same results.

Regards Jerry

Mel · #4 11-05-2009, 08:26 AM

Remember, the "P" lead MUST be disconnected from the mag to perform the test. Otherwise it will ground through the mag points.

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gfr56md · #5 11-05-2009, 08:52 AM

Now with P lead disconnected I get zero resistance with mag switch off and infinite resistance with switch on.

From past forums I see that you recommend connecting the shielded portion of the wire at both the mag and the switch. Is that correct?

Thanks again
Jerry

Mel · #6 11-05-2009, 10:11 AM

Quote:

Originally Posted by gfr56md

From past forums I see that you recommend connecting the shielded portion of the wire at both the mag and the switch. Is that correct?

That's the way I do it. Others do it differently. Some use aircraft ground which is fine if you don't get ignition noise in the radios.