I broke a flap off my carb as well. I tried the JB weld but found that there was just too much vibration on the carb so it just splintered and came apart. What I did was to drill a hole through one of the other flaps and into the elbow joint I was using and tap it. Then screwed in a small screw to hold it in place. I sealed the new joint with JB weld to prevent air leaks. This fix made it as solid as a rock.