Stihl HL 90 Product Instruction Manual - Page 20

273BA006 KN 266BA027 KN English Cleaning the Air Filter If there is a noticeable loss of engine power 4 1 2 Engine Management Adjusting the Carburetor Exhaust emissions are controlled by the design of the fundamental engine parameters and components (e.g. carburation, ignition, timing and valve or port timing) without the addition of any major hardware. The carburetor of the machine has been adjusted for optimum performance and fuel efficiency in all operating states at the factory. Setting the idle speed N Turn the choke knob to g N Take out the screw (1) and remove the filter cover (2). N Clean away loose dirt from around the filter. N Grip the filter element (3) at the cutout (arrow) in the filter housing (4) and remove it. N Fit a new filter element. As a temporary measure you can knock it out on the palm of your hand or blow it out with compressed air. Do not wash. N Replace damaged parts. Installing the filter N Install the filter element in the filter housing and fit the cover. N Insert the screw and tighten it down firmly. LA Engine stops when idling N Let the engine warm up for approx. 3 min N Slowly turn idle speed screw (LA) clockwise until the engine runs smoothly - the cutting attachment must not rotate Cutting attachment turns when idling N Turn the idle speed screw (LA) slowly counterclockwise until the cutting attachment stops moving - then turn another 1/2 to 3/4 turn in the same direction WARNING If the cutting attachment continues to keep rotating in idle even after adjustment, have the machine checked by a servicing dealer. 18 HL 90 K