P51-- You needle setting technique is just fine -
I get to setup lots of engines and the typical results -a bit cold blooded -till warm -is very common on well setup aerobatic .
At last TOC- I started all contestants-- so I got to se how the engines all responded .
Typical cold starts required a brief warm up -
These were all 150 DA and 3W engines but most acted the same.
I find exactly the same results on all sizes of my own gassers.
Loading up on taxiing is typically a characteristic reserved for glo engines.
And gas engines set too rich.
Is your engine mounted inverted?
Does it do the same thing if you hold it flipped to upright - or on it'sside? The little Sportsman ZDZ40 (reed valve) did this --BUT if I tilted the engine to aprox 8:00 -it all cleared up .
It is not a typical characteristic of the DA50 - as far as I have seen.
We run 32-1 syn right from the get- go and the engines all break in just fine.