Remove the gas line from the carb and put it in a container to catch the gas. If you can, remove the pickup from the tank, or disconnect the line at the top of the tank. Fill a small bottle 1\2 full of gas and submerse the line in it. Crank the engine and compare the output of the pump to before. Better, you have a problem getting the gas out of the tank. Same, you have a pump\pule line problem or the fuel line itself. Connect a short line from the bottle and to the fuel pump input. Try again. Better, plugged fuel line. Same, pump related.