I just traded for a 72 big 40. Guy said it was running last August was the last time it was started. It will crank and run a second with starting fluid but acts like its gettin no fuel. The valve under the bowl is open, has a new filter, and fuel comin through line. Could this be a carburetor issue or if the plunger is bad would that cause it? I've never had a big 40 only Lincoln's and a couple Miller bobcats so I'm in the dark on fixing this one