1925 Dodge stops after 5 sec

Hi Everyone, I'm new to this site and hoping someone out there can help me. I restored a 1925 Dodge tourer a couple of years ago, total engine rebuild as original and have had it running well. Last outing it died on me, restarted after a quick inspection, died again. It was dying first about every 2 mins, then reduced to about 5 secs where it is now. I have ample fuel to the carby, the float is good, air intake clear, spark as per timing light is going as the engine dies. Vacuum good, plugs cle

Hi there, Re the vacuum tank not shutting off the vacuum line and the rich vapour bypassing the carby direct into the manifold. I stripped the vacuum tank expecting the float to have liquid in it, however it was in excellent condition. When I was draining the tank there was a "clunk" inside as though something had hung up and dropped. On inspection, there wasn't anything that I could fault, everything operated smoothly, so thought it was just one of those things that can happen. Definitely could