More than likly the carb is a Zama. Much like a Walbro but from China. They work Ok. Have you had the carb apart? If you haven't you should do so and blow out the all the little passages. Then put it back together (as long as all looks well) and try it again. You can rough set both needles at 1 1/2 to 2 turns and work from there. High speed first. All this is assuming that the ignition is Ok.............Bob