I just finished overhauling a Lycoming O-360; it's currently on a stand, i.e. it's not in the aircraft. I replaced the capacitors and point gaps on both the L and R mags. I adjusted the E-gap and engine timing at 25 degrees as per the engine plate.
I have two toggle switches connecting the P-leads to ground: one for the R mag and one for the L mag. I turned on the L mag only to start and when I started the engine for the first time it fired up right away. But when I then turn on the R mag the engine just stops.
I can start the engine on the L mag only any time. As soon as I turn on the R mag, the engine dies. It’s as if when I turn the R mag on the L one goes off. I did everything I could to troubleshoot but I did not find where the is. What could be the issue?