Stihl BG 85 Instruction Manual - Page 21

Standard Setting English 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 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. 295BA085 KN 295BA086 KN Engine stops while idling N Turn the idle speed screw (LA) clockwise until the engine runs smoothly - then back it off a 1/4 turn from that position. Erratic idling behavior, poor acceleration (despite correction to setting of LA screw). Idle setting is too lean N Turn the low speed screw (L) carefully counterclockwise, no further than stop, until the engine runs smoothly and accelerates well. Erratic idling behavior, engine speed drops when swinging the machine Idle setting is too rich N Turn the low speed screw (L) slowly clockwise until the engine runs and accelerates smoothly. A slight correction of the setting may be necessary if the engine does not run satisfactorily: N Carry out the standard setting. N Warm up the engine. N Turn high speed screw (H) slightly clockwise (leaner) - no further than stop. NOTICE After returning from high altitude, reset the carburetor to the standard setting. If the setting is too lean there is a risk of engine damage due to insufficient lubrication and overheating. BG 55, BG 65, BG 85, SH 55, SH 85 19