Stihl BR 450 C-EF Instruction Manual - Page 21

Adjusting the Carburetor 3 General Information 0002BA089 KN N Remove the filter element (3). N Replace dirty or damaged filters. N Fit the new filter in the filter housing. N Fit the filter cover. N Fit the screws and tighten them down firmly. The carburetor comes from the factory with a standard setting. This setting provides an optimum fuel-air mixture under most operating conditions. Preparations N Shut off the engine. N Check the air filter and clean or replace if 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 (not in all models, country-specific) in the muffler and clean or replace if necessary. Standard Setting English L H 0002BA082 KN N Turn high speed screw (H) counterclockwise as far as stop (no more than 3/4 turn). N Turn the low speed screw (L) clockwise as far as stop, then turn it back 3/4 turn. Adjusting Idle Speed N Carry out the standard setting. N Start and warm up the engine. L LA 0002BA083 KN Engine stops while idling N Turn the idle speed screw (LA) slowly clockwise until the engine runs smoothly. BR 450, BR 450 C 19