That 20x10 Bambula prop is way too big for that engine. It's almost too much for the 2.10. My 2.10 turns the Bambula 20x8 at 7300 slightly rich, 7600 peak.
Do what Jim said, turn the disk to center tic. It should transition ok, may need a lttle tweaking. If you still have that unusual midrange problem with the disk at center you have some other major problem. Time to take the carb apart and inpect it for dirt or debris. Be sure to inspect the spray bar disk for debris in that fuel jet. Make sure to use a filter on your fuel line.
That paper gasket on the high speed needle can come apart and get inside the carb. You gotta be careful turning that high speed needle assembly when it's still a little tight. It needs to be very loose while turning it or it will tear that gasket. So maybe that's what happened? That was not lock tite you saw it was a paper gasket coming apart? Many people reposition the banjo by loosening that high speed needle assembly.
ORIGINAL: por924
Jim, I checked all that you have suggested even before I ever flew the plane and all was good. I broke the engine in on 0% (3 gal) with the cowl off then started flying it with the cowl on still slightly rich. I was getting 8400 with a Zinger 18-8 but not quite yet unlimited vert. Everything was working perfect up until I tried a Bambula 20-10 prop and then everything went out of wak. It would spit fuel out of the carb and wouldn't go past 5000 rpm so I started testing and tuning and that's when I adjusted the low end. I even took the High speed needle out all the way to check for debris and all I found was what looked like factory applied thread lock for the banjo fitting assembly. I reasembled everthing and went back to the Zinger 18-8 and things were much better but now I have the transition prob, to make a long story short!