just to throw in my two cents i would say check the air filter and air tube to the carb for any blockages such as wasp nests, mouse nests, etc.
check for fuel flow to the carb but also through the carb by removing the plug in the bottom of the carb. with the fuel on no more than two turns open it should be a steady stream. one of the three brass screens may be clogged after sitting so long.
check the condition of the plug wires and make sure they are in the correct firing order, 1243(with 1 being nearest the radiator) although it would probably start even if one was switched.