I would suggest that the low needle needs to be richened up. Do this in very small increments until the stalling goes away. Leaning out the low needle will sometimes cause the engine to starve for fuel and cause it to stall. I have a DLE 20cc which is in its 3 year and the only thing I have done is checked to make sure the small screen inside the carb is clean. It was so I put the carb back together, fueled up and it started and ran great on the first flight on this season.