Back in the day when I drove a stovebolt as my daily driver I would sometimes experience carburetor iceup in the venturi. Usually when it was 40-50 degrees outside. If I used the isopropal alcohol it would take care of the problem. The symptoms were pushing the gas pedal further down, and going slower, and slower until the engine quit. The engine heat would melt the ice in about 10-15 minutes. As a rule, I have hardened seats installed on heads of engines that I rebuild because of todays unleaded gasoline.
