The attached picture is from my single rotor PP engine after about 10
hrs running time. Most of the time was running at WOT and 6000RPM. fuel
flow was around 8gph.
If this an indicator of mixture distribution at ignition, what does
it mean? if anything. Has that been observed by anyone else?

Richard Sohn
N2071U

You got me. I have never seen anything like that.
What kind of oil are you mixing?

Paul Lamar


Richard,

Could the spark plug be kinda bottoming in the threads and distorting the
rotor housing? It is polished right at the sides of the plug hole, but burnt
farther out.

Dale Davies