1996 Evinrude 225hp v-6 Carburated outboard. The top two cylinder spark plugs keep fouling after 3 to 4 hours of 3/4 throttle. I am not trolling at lower speeds. The plugs have a hard charcol crystalized residue on the electrode. the other four plugs look normal. i just replaced the stator and had the spark and voltage checked. the compression is good on each cylinder. do you think the top two carbs are running rich? if so is the an adjustment on the front of the carb?
