If there is an air leak between the carb and the engine, the vacuum pulse port will leak and the carb will not draw fuel. The pump side of the carb may have dried out too. Remove the gas line off the carb nipple and squirt WD-40 in the hole in the nipple. Put the gas line on and see if it will draw fuel. If your fuel line is loose anywhere from the carb nipple to the tank, it can leak air and not draw fuel.