Stihl FC 90 Product Instruction Manual - Page 23

Cleaning the Air Filter Engine Management English Adjusting the Carburetor If there is a noticeable loss of engine power 4 1 2 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 273BA006 KN 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 comes from the factory with a standard setting. This setting provides an optimum fuel-air mixture under most operating conditions. With this carburetor it is only possible to adjust the high speed and low speed screws within fine limits. Standard Setting N Shut off the engine. N Mount the cutting blade. N Check the air filter and clean or replace as necessary. N Check that the throttle cable is properly adjusted - readjust if necessary - see chapter on "Adjusting the Throttle Cable". N Check the spark arresting screen and clean or replace as necessary. N Install the filter element in the filter housing and fit the cover. N Insert the screw and tighten it down firmly. FC 90 21