You never need a new carb. They are expensive,and unless physical damage has been done to it ,it's ok. I don't remember how old your bike is,but the rubber cup on the accelerator pump does wear out. I would take the pet cock off the tank and rinse it to be sure there is not any dirt or crap in there. Then just get a new float and needle seat,and new gaskets for the carb. Sometimes the float will absorb gas inhibiting it's proper movement..Get the xcell pump cup too. As the other gentleman said,set it all up to stock specs. It's a basis and a starting point.He gave good info. My best guess is that you got some crap in there and damaged the float needle seat,and you have adjusted the float to compensate for that,but there is not enough fuel to run the bike. Re-think,and go slow. The fix is cheap. Don't buy a carb. Clean the tank,clean the pet cock on it,replace the parts I mentioned,adjust it properly,and your problem will go away.