I have three KBL-26A trimmers and all are one year old. One runs real strong and the other two not so good. I took the carbs off all of them about 2 months ago and cleaned them out, so they all got the same treatment, but one just runs faster. Does anyone have any idea why the other two are lagging? I have removed the spark arresters on all of them right from the beginning. I am using Opti-2 oil and do not have any smoke. I just wonder if there reall might be some adjustment or trick to "hopping-up" these little engines.