RE: DA 50 fade with outside manuvers
If I remember correctly one of the guys here, Nogyro I thinks it was.... had an issue like this and found that the fix was to solder some 5/32 tubing to the center of the carb diaphragm cover. He drilled out a new vent port in the cover and soldered the stock one shut. Then he ran tubing into the fuse out of the cowl. It seems that inside and outside maneuvers will produce different air pressures inside the cowl and the carb will meter differently as the air pressure changes.
On a similar note I had a Cline regulator mounted in a Saito 100 powered 65 inch Kangke Cap that did some odd things like this. I had the Cline mounted on the left side of the firewall, opposite the cylindar which was mounted horizontally to the right side of the fuse. Get this....on a right side knife edge the plane flew fine and the engine ran strong but on a left side knife edge the engine would go rich and lose power. I moved the Cline and the problem went away completely. The reason I'm bringing this up is because the Cline is baically nothing more than a plastic housing with a Walbro needle and diaphragm mounted to it, operation is almost identical to the way the needle/diaphragm works on a gasser. when flying the Cap on a KE I never could get the nose higher than 30 degrees which shows that it doesn't take a huge deviation from level flight to alter the pressure in the cowl on some planes.