Parts are hard to find. My carb was leaking; here's how I fixed it.
Remove float bowl, remove float and bronze uptake siphon. Clean bowl, float & siphon with carb cleaner.
You will need a fine wire to clean out orifices of uptake fitting.
Gently bend bronze float linkage (yoke) so that float will close fuel valve when bowl is full. Lube throttle & choke. Reassemble.
Worked for me.
forrest, July 2009