This is the second of two issues I'm having with my P-Mags on my RV-8 with a Lycoming IO-360-M1B. I've been running dual P-Mags ever since I bought the airplane about 150 hours ago. The other issues is erratic RPM readings, which I posted about separately, so as not to cross streams. I believe this to be completely unrelated.
It has recently become harder to run lean of peak. As I approach peak EGT, the engine seems to develop a slight stumble. It's not what I would describe as roughness, but rather an almost rhythmic stumble. Today I attempted Mike Busch's LOP mag check in flight. I ran lean of peak and alternately switched off each mag. The engine ran very rough and exhibited lots of popping on each of the left and right mags when running individually.
I thought that the problem might have been old spark plugs getting weak, as I only recently learned to replace my automotive plugs after about 100 hours. The old ones had approximately 150 hours on them and I just replaced them with new NGKs: BR8ES Part Number 3961, but alas, the engine acts the same with the new plugs. I gapped them all to between 0.032 and 0.035. Any ideas on what might be causing this behavior?
Thanks in advance for the help!
Dan
It has recently become harder to run lean of peak. As I approach peak EGT, the engine seems to develop a slight stumble. It's not what I would describe as roughness, but rather an almost rhythmic stumble. Today I attempted Mike Busch's LOP mag check in flight. I ran lean of peak and alternately switched off each mag. The engine ran very rough and exhibited lots of popping on each of the left and right mags when running individually.
I thought that the problem might have been old spark plugs getting weak, as I only recently learned to replace my automotive plugs after about 100 hours. The old ones had approximately 150 hours on them and I just replaced them with new NGKs: BR8ES Part Number 3961, but alas, the engine acts the same with the new plugs. I gapped them all to between 0.032 and 0.035. Any ideas on what might be causing this behavior?
Thanks in advance for the help!
Dan