I have a '73 40. I rebuilt the carb, replaced fuel filter, removed and drained gas tank, and purged all lines with compressed air. No crap or debris was seen throughout the fuel system. Vehicle will not start without pouring gas in the carb. Fuel level in the float bowl is halfway up the sight glass. Once running, the motor runs perfect, but only with the choke on. Take the choke off and the motor idles fine, but stumbles when you stab the gas pedal. No issues with idling, it idles fine warm or cold. Accelerator pump is new and linkage operates properly. I did not replace fuel pump, but it looks new from PO. Also did the vacuum leak test by placing a piece of cardboard over the carb air horn with good results (i.e. engine died without increase in idle.) Anyone have any thoughts on this? It's got to be a fuel starvation problem, no?
