A bit of background. When I first bought 30FM I had a horrible time with engine starts. Hot, cold, flooded normal start, did not matter. I was stranded three different times at a fuel stop. I was ready to sell till maintenance finally took a good look and determined that both mags were not performing correctly and one was even loose and could not hold timing. Mags were replaced and for the next five years I’ve had absolutely no problems staring under any condition .
Fast forward, I picked up 30FM from MX after its annual. It was time for the 500hr mag inspection. Did an IRAN on both. Now I have a 120RPM drop on both, before the IRAN the drop was 90-100RPM.
Another issue was with the spark plugs. I was told they were not performing correctly when hot. MX had a hard time starting the airplane when it was hot. For five years I had no issue. They did not have any new plugs but did have a used set that were check out as good. I said to go ahead and replace the plugs with the used ones. When I did the run up the engine ran terrible on either plugs, left or right did not matter. Replaced with original plugs and it ran as before, but with the 120RPM drop on the mags.
Question(s);
Mag drop is not acceptable for redone mags, correct?
Could the plugs be causing my issues with starting? (I had them recheck the timing)?
How do I know plugs are bad?
Any special considerations when changing plugs?
thanks
Angelos