Stihl MS 171 User Guide - Page 87

12 a 1 533RA370 TG 533RA371 TG 533RA220 TG : Inspect the tip (arrow) for damage or wear and replace the screw if necessary. - Screw home high speed screw H as far as stop. - Carry out basic setting, b 14.5.1 14.5 Adjusting the Carburetor 14.5.1 Basic Setting The basic setting is necessary only if the high speed screw H or low speed screw L has to be replaced or after cleaning and adjusting the carburetor from scratch. : Screw down the high speed screw H (1) clockwise onto its seat. : With the high speed screw H (1) against its seat, unscrew it one full turn counterclockwise - this is the basic setting. : Screw down the low speed screw L (2) clockwise onto its seat. : With the low speed screw L (2) against its seat, unscrew it one full turn counterclockwise - this is the basic setting. : Do not push on the limiter cap (1) as far as stop against the carburetor body (2) because it will be damaged. Maintain a minimum clearance of "a" = 1 mm (arrow). The high speed screw H now has a limited range. The standard setting is obtained by turning the high speed screw H counterclockwise until it engages in position. - Remove the limiter cap from the high speed screw, b 14.4.9 1 It is necessary to carry out the basic setting after removing the limiter cap. 533RA372 TG Always install a new limiter cap. First position it so that its lug is below the stop (arrow) and then press it onto the high speed screw. : Press the limiter cap (1) onto the high speed screw H. 86 MS 171, MS 181, MS 211