Mag-earthed or live?

[John001]

Hi,

quick question about mags:

During run-up checks upon selecting an individual mag, are you earthing that mag and checking running on the other or are you selecting only that mag and therefore earthing the other?
I`ve managed to confuse myself!:)

regards

John.

[ShyTorque]

Where it says "L" you are earthing the right mag to disable it and vice versa.

[fireflybob]

Another point worth making is that earthing the magneto is not "fail-safe" - another reason why props should always be treated as live!

If, when you do a mag check, there is ZERO drop when you select an individual mag then this would point to a live mag, in which case I would advise a check at idle power and momentarily selecting off and making sure the engine ceases to fire. If it continues to fire then you have a live mag the defect needs fixing asap!

[blue up]

If you have the Leburg ignition then it gets a little confusing. Switching off the left ignition switch cuts supply power to the left ignition coil and vice versa. It is a "fail non-operational" system so that if the switch breaks, the ignition stops.