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

Hi Richard;
The centerline smudge running left from both plugs is a sign of heat.
Were the smudges there previously?
It might be blow by, grooved surface, apex clearance?
Have you checked the rotor housing surface and apex seals with a ruler
and back lighting for flatness?

Those orings also appear to be too large.

Cheers
Cary