bp88mustang

how would i kno that the needle valve is good or not???????

ok i just got done putting the quad back togeather just had the frame powdercoated, so i put everything back togeather n i start her up.then the right carb starts to pour gas out of the overflow, i turned it off n with the gas on it keeps pouring out.so i take it all apart n the float still moves which i thought would be stuck, is there ne way i can check if it is my float? if not what could it be?i need help!!!!