You didn't say what engine or carb. you have but if it,s a Roch. model B make sure the gasket under the carb has a passageway from the vacuum hole in the base to the intake manifold. Check the power valve in the carb. The piston should should work up & down freely & the ball should cover the hole when the piton is up. If it's black carbon you are getting on the plugs it's got to be over fueling. The choke plate must be vertical after warm up.
