Check for fuel first. Possibly plug the vacuum line at the manifold, temporarily, fix that later. If you have no fuel to the carb, check to see if there is fuel to the pump. Disconnect the line and see if if runs out. From wht you have said, this sounds like the old junk in the fuel tank problem, closing off the tank outlet. If you were low on fuel, the pump could suck the junk into the system and cut off the flow. Sometimes after sitting the fuel will start to flow again, only to clog when the pump starts. A short burst of air could blow the clog back into the tank and allow a very short term fix.
