Chances are is that you dont need to purchase a new one. Not unless the inside is corroded beyond belief. The fuel systems on these scooters are very sensitive to the smalles particles of dirt. Your talking about carburetor jets and openings that are really really small, so the smallest particle will effect it. Here is what I would do. I would start by taking off the fuel petcock located under the gas tank. Drain the tank completley. Also take out the fuel strainer that should hopefull should of have come out with the petcock, if not just take some pliers and pull it out. Clean the petcock and strainer. Get a brand new fuel line and new fuel filter. Install the petcock, strainer, fuel line and filter with some fresh gas. Then you should clean the carburetor once again, thoroughly. Take a 8 guage wire and strip about a half inch off it and use the exposed wire to gently clean the area where the needle valve sits. Also, I would clean the air filter element and install a new spark plug. Also, take the gas cap off and spray it down with carburetor cleaner paying attention to the vent hole. It sounds like a big process but it can be done in under a half an hour. It's just a process of elimination.
