chinese atvs?

I have a 4 cycle, All Road chinese made four wheeler, I've had problems starting from when I first got it shipped in, the battery was bad so i hooked it up to a separate power source and it turns over but never actually starts. I'v cleaned the carburetor, and now the carburetor is good, i have fresh gasoline, and all of the lines put out. except where the gas tank meets this part before the gas filter, it doesn't seem to put out any gas. is it broken or am i just using it wrong?  

On my quad between the gas tank and the fuel filter there is a shutoff valve.  On mine it is manually controlled, and I had trouble when my quad was new because it was plugged.  I had to drill it out.

I've read that some quads have a vacuum operated shutoff valve that automatically shuts off the gas whenever the engine isn't running (vacuum goes away, shutting off the gas).  Seems like a good safety feature since a leaking carb could dump the entire gas tank onto the garage floor out the carb overflow tube, where the water heater or furnace could ignite the fumes.  In practice these don't work well and many replace it with a manual valve.

I don't know if that is the device you are describing, but since no one else is jumping in here I thought I would raise the possibility.