A bad bunch of NGK CM6 plugs got out too. The porcelain seal leaks and you will find a brown ring of burnt oil on the outside of the plug where the porcelain meets the metal shell of the body.
I would get a new set of plugs and gap at 0.015". My 3W-100 still runs strong and as reliable as a clock after more than 600 flights. Original 3W ignition, DA ignition caps.