running lean,rough idle
Make sure the cap on the valve cover is washed out in kerosine and allowed to dry. If it is blocked it causes rough running. Make sure the carbs are balanced and not set too lean. Sometimes the smoother running when you disconnect the breather hose can be a result of the faster idle that results. At slower RPM the rough running is accentuated. If everything is set right a slow idle can be sustained.
thanks for the info..i'll check the oil cap..my midget is a1979 with a 1500 engine and it only has one carb on it.. thanks again..if you think of anything else i would be thankful..