Thanks will keep that in mind. Last evening I pulled the carbs, cleaned and swapped inlet needles and seats and reset float levels. And I also checked the plunger to be sure it was free and the lifter was not putting any pressure on the plunger.
Will take it for a test ride tonight to see if I get a black spot on the right plug again or see if it moves to the left. Oh and I used carb cleaner and compress air to clean things out.