Stihl MS 192 C-E Product Instruction Manual - Page 40

English Erratic idling behavior, poor acceleration N Carry out standard setting on low speed screw (L). N Idle setting is too lean: Turn the low speed screw (L) counterclockwise until the engine runs and accelerates smoothly. It is usually necessary to change the setting of the idle speed screw (LA) after every correction to the low speed screw (L). Fine Tuning for Operation at High Altitude A slight correction of the setting may be necessary if engine does not run satisfactorily: N Check the standard setting. N Warm up the engine. N Turn high speed screw (H) slightly clockwise (leaner) - no further than stop. If the setting is too lean there is a risk of engine damage due to insufficient lubrication and overheating. Spark Arresting Screen in Muffler In some countries the muffler is equipped with a spark arresting screen. N If the engine is down on power, check the spark arresting screen in the muffler. N Wait for the muffler to cool down. N Remove the sprocket cover. N Take out the screw (1). N Remove the baffle plate (2). N Remove the spark arresting screen (3). N Clean the spark arresting screen. If the screen is damaged or heavily carbonized, fit a new one. N Refit the spark arresting screen. N Fit the baffle plate. Checking the Spark Plug Wrong fuel mix (too much engine oil in the gasoline), a dirty air filter and unfavorable running conditions (mostly at part throttle etc.) affect the condition of the spark plug. These factors cause deposits to form on the insulator nose which may result in trouble in operation. If engine is down on power, difficult to start or runs poorly at idling speed, first check the spark plug. N Remove spark plug - see "Starting / Stopping the Engine". N Clean dirty spark plug. N Check electrode gap (A) and readjust if necessary - see "Specifications". N Use only resistor type spark plugs of the approved range. 000BA002 KN 38 MS 192 C