Abstract: A method of operating a two-stroke cycle internal combustion engine having at least one exhaust port communicating with each combustion chamber of the engine and an exhaust valve operably associated with at least one said exhaust port to control the timing of the opening and the flow area through said exhaust port between maximum and minimum values, the method comprising advancing the timing of the opening of the exhaust port in response to idle or low load operation to the maximum extent to maximize the flow area through the exhaust port. Other engine management operations disclosed and claimed include: positioning the exhause valve to reduce the flow area to the minimum extent on cessation of operation of the engine, and impacting the exhaust valve against the limits defining the maximum and minimum values of valve movement to promote dislodgement of carbon deposits.