SonexBuilders.net

My Sonex has a Great Plains 2180 cc engine serial number 071403-0113FDIC. The engine has about 150 hours. Lately during preflight run-up the magneto has been showing about 150 RPM drop when switched from "Both" to "Mag". Up till now, the drop has been 50 RPM or less. I would like to check the points and their gap, but I can't find any information on this in my Engine Assembly Manual. On the page for Scheduled Maintenance, at Magneto it says "See magneto section", but my manual does not have a magneto section.

I would appreciate any information anyone can provide on magneto maintenance and point gap.

Skygeezer

I would think you should check the timing between the two ignition systems first I have the almost same engine with over
400 hours on it and the mag shows no problems.

Thank you very much. It was a major help to get access to the maintenance manual. From what I've read so far, it does sound like timing is the first thing to check.