I have replaced the spark plugs twice in my 1949 1/2 3100 with a 216 cu.in. Granted the truck has seen very little road time and mean very little. It has sat idling for extended periods of time 30 minutes or so at a time, or until it reached operating temperature, two to three times a week. I used AC Delco R45S plugs which I understand are a hotter plug than the R43's. I have the idle circuit screw set a 1 1/4 turns out from the stop, which I get 20+ in. of vacuum with no variation at idle. Idle set a 475 RPM. Would long periods of idling cause the plugs to fuel foul to the point that the truck would begin to run rough? NO oil residue on the plugs, no carbon ash, just a light black shiny residue on the electrode, ceramic insulator. Truck starts up on the first try, but runs like multiple cylinder misfires on the fouled plugs. Timing set on the BB and 3 more degrees at the distributor base. Any ideas or suggestions?
Tim
