Stihl BR 550 Technical Guide - Page 11

Technical Information 08.2005 5. Service notes 5.1 Carburetor adjustment Page 11 The limiter caps are fitted over the knurled head of the adjusting screws. The stop on the carburetor housing serves as a limiter. 5.1.2 Maintenance / repair 270° 270° 249TI004 KN With this carburetor, the high-speed adjusting screw (H) and low-speed adjusting screw (L) can only be adjusted by the user within a range of 270° (3/4 turn). The carburetor has been adjusted for optimum performance and fuel efficiency in all operating states. Fine adjustments are still possible to adapt to changed conditions of work and use such as changes in elevation (mountains, sea-level). 5.1.1 Mechanical design When servicing, the limiter caps must be removed when exchanging damaged adjusting screws or to clean the carburetor. . Remove limiter caps (2) with puller 5910 890 4501 (1). Used caps may not be reused, as they are damaged when pulled off. Adjustment after maintenance / repair . Check air filter and replace it if necessary. . Check spark arresting screen (if installed) - clean or replace if necessary. . Check the throttle cable . Low-speed adjusting screw with sealing ring (1) . Limiter cap for low-speed adjusting screw (2) . High-speed adjusting screw with sealing ring (3) . Limiter cap for high-speed adjusting screw (4) . Stop (5) . Idle speed adjusting screw (6) TI_08_2005_11_01_02.fm