ORIGINAL: RTK
Albatross- There is a fine line on the 110 between perfect on the high and too lean. If you are a little rich on the high it can cause the upper mid range stumble.
If you let your engine idle for 20 or so seconds (on the ground while restrained) and goose it does it stumble? If it does not stumble while motion less on the ground, you will have to look at other causes.
RTK
I see what you mean, the needles of this engine are very sensitive.
Stumbles on the ground. However typically after hand starting the engine just before the flying session, when testing the engine on the ground:
From idle goose, stumbles then finally reaches 6300, 6200.
Throttle back. let the engine idling, wait some time (no sure how ), goose then the transition is just fine this time.
Taxing, then open the throttle, exactly when is gaining altitude or before the engine stumbles.
I am getting used to this stumble, however is pretty scary. I don' think is right.
By the way, I am positive I am working my way to the lean area since the two maiden sorties I did I noticed some smoke coming along, at that point I started leaning the needles. It has been 4 weekends so far after that maiden. 3 flights each weekend only 7-8 mins long. Before that I ran the engine on the ground on a test stand at no more than 4000 rpm, reach 2-3 gals on ash less oil.
Wish I could get my temps that low, but I haven't finished my baffling work yet. By the way how hard were you pushing it in that chart above?
Between the 5 and 7 mins mark of that plot I am sure corresponds to the time I was torque rolling the airplane.