SERIAL NO. OB170699,REBUILT CARBS,CHANGED PLUGS,STILL HAS TROUBLE GETTING TO PLANE ,,NOT ALL THE TIME,STUDDERING AND THEN ,OFF AND RUNNING,SOME ONE SUGGESTED SWITCH BOX,,SOMTHING ABOUT A LOW RANGE ,AND HIGH RANGE SOMTHING OR OTHER ,I AM LOST ,HE ALSO SAID IT MAY BE TRIGGER,,,ANYWAY OF CHECKING...