Jab ign coils

[Corby202]

I don't know if everyone does a mag check before shutting down but I am glad I do.
I flew for an hour on friday, no problems were experienced during the flight. Did a mag check before shutting down the engine and the engine cut out when on #2 (rh). Checked a couple of times with the same result. It was getting late so I started checking things the next morning. The resistance readings on both coils were the same primary and secondary and matched Jabiru published figures (depending on what page you look at in the manual). Kill switch was fine, dismantled the distributor, a tiny amount of oil in one hopefully from initial assembly but certainly none on the rotor.
The ign coil gap was 15 thou instead of 10 so I set both correctly. The engine started straight away and ran fine on either mag. Flew for 1/2hr (did not try switching the mags off in the air) and did a mag check after landing. Same thing, the engine would not run on the #2 mag. Pulled the cowls off straight away, the coil was warm but certainly not hot. Checked the resistance again and the primary had now changed to 5 ohms on the #2. #1 was still reading 1ohm.
Need to order new coils now from Jabiru.

[vwglenn]

I had a similar problem. Long story but it turned out that one of my mags was picking up a ground from the RDAC. Similar symptoms. Both ignitions worked fine until the engine got warm. RDAC is picking up the RPM from the Left Mag. Simple flip of a dip switch on the RDAC fixed the ground issue.