All Plugs Fouling on Right Bank

What year 273?

Don't use brake clean as a vacuum sniffing agent, ones containing chlorine can be deadly when vaporized by heat, they will produce phosgine (sp?) gas, the same stuff used by the Germans in WW1.

Black soot dry, would be carb problem, black soot wet could be sucking oil or too much fuel, sniff the plug; does it smell like gas?........as already stated, could be speck of dirt in air bleed, possible bent hanger