Fouling Plugs

The 383 in my 65 Newport fouled the plugs once and stranded me. All it seems to take is a light coating of carbon. Replaced the plugs and fired right up. That was with the original Stromberg 2 bbl carburetor. Can't recall how I fixed it, but I do recall rebuilding the carb once and running on it another 2 years with no similar problems.