there is a little screw at the bottom of the carb. make sure that the screw is all the way turned in
if that screw is open a little bit, the gas will leak out of that long straw. It is a drain screw
It is all the way at the bottom of the carb, towards the back of the bowl.
As fot he battery, all the battery does is rn your lights, and help it to start. The qt50 has an "electric assist starting system" which makes it easier to start. It will still run with out the battery though. Just watch out that it doesnt blow the headlight.