More than likely it is a fuel obstruction somewhere between the bottom of the tank to where it leaves the carburetor.  I would either remove the sediment bowl from the tank and clean it first and blow thru the gas line from the carburetor end.

The only true way to clean a carburetor is to soak it in a basket of carburetor cleaner. For that size of carburetor they sell a gallon can with a basket.  I personally boil any carburetor I am cleaning before I take it apart. Some times I boil it again if it is real cruddy before I soak it in the cleaner.  The carburetor cleaner in a spray can will not do what is needed. It works best to clean your hands or the outside of a carburetor while using a wire brush.