Having owned 4 qt50's now I'll give this a go. Fortunately I believe your problem is easily corrected:
The screw on the very bottom of the carb bowl is to drain off fuel. It should be screwed in all the way. If it isn't, your bowl won't be able to fill itself completely/properly with gas thereby likely causing your symptoms of no acceleration-stall, and leaky leaky gas. Solution: tighten that little brass screw on the bottom of the carb all the way in and ya should be good to go. Yay! Let us know how it goes.