We had just replaced the magnetos on a R-985 and were pulling the prop through by hand (mags OFF) prior to start. Guess what? It started all by itself!
So why weren't the mag p-leads grounded? The guy who did the bench test put a slip of paper under the safety contacts so he could test the spark. He then forgot to remove said paper, and when we connected the p-leads, the paper prevented the grounding contact.
ALWAYS treat the mags as though hot!
