Al, something else to think about. If you run lean mixtures is you may want to run the widest plug gap you can easily fire. The reason is that when doing lean operation studies engine manufacturers have found that a strong spark and wide gap is best to reliably ignite lean mixtures

Lynn writes:

Fresh plugs gapped tight.

Hum-m-m; seems to be some difference of opinion.  My B9EGVs are gapped at about .025; or a few thousands over.

I did some adjusting yesterday on the EGT spread.  It clearly varies with rpm, and I suspect on my setup that is primarily due to air flow variations.  I had close to 100F spread at low power (2000 rpm) which decreased with increased power. Using modes 4 & 5 on the three rotor I adjusted mixture so the temps are within 20F at about 15.5” MAP (below staging). It required leaning 1 and 2 to get them close to #3.  At WOT on the ground I then find that rotor 2 is 50-60 hotter than the 1 and 3 which are relatively close.  I’ll do some adjusting in the air at cruise conditions.

AL G