Just when I thought I had everything sorted out... I've started to have a new issue. I'm hearing a sound, hard to describe but something between a rattling and popping sound, only at full throttle. I can hear it in the plane and people on the ground can hear it, too, when I take off. No noticeable effect on power or rpm, unlike the magneto coil issue I had last year which caused a brief rpm drop. Engine is a Mosler CB40, with an almost new (30 hour) Slick 4316 magneto with two poles shorted out, .016 gapped BPR5ES plugs with Great Plains adapters for the shielded Slick harness. Mag timing is correct at 28° BTDC. I put in new plugs and set the valves with the oil change less than 5 hours ago. I haven't yet, but will, try new plugs even though the ones in there are almost new, recheck the valve clearance, and if all else fails try swapping with an identical new magneto that a friend has for his Minimax but hasn't installed yet.
Dana
Dana