I have been dealing with this issue for a few months now. It will not start unless I choke it, it will stay running until I let the choke go then it dies. I have new installed new tank, lines, bulb, vro delete fuel pump, plugs gapped at .30, rebuilt carbs 2 times soaked them took the Welch plugs out compressed air to clean passages, set floats, compression is 120 on number 1 and 117 on number 2. Runs great wide open. I’ve set all the linkages to the correct lengths and still no luck. I’ve sprayed starting fluid around to check for leaks to see if it stays running but no luck. Nothing changes when I try and pump the bulb while it’s running. I unscrewed the gas cap so that there’s no vacuum issues there. Any help would be great thanks.