Important: Before making adjustments, ensure that the engine is off, and the blower is cool to the touch.
1. Locate the Carburetor: Identify the carburetor on your BG55 blower. It is usually located on the side of the engine and is typically a metallic or black component with several adjustment screws.
2. Identify the Adjustment Screws: On the carburetor, you will find three adjustment screws:
- Low-Speed (L) Screw: This screw controls the fuel-air mixture for low engine speeds, generally used during idling and low-speed operations.
- High-Speed (H) Screw: This screw controls the fuel-air mixture for high engine speeds, mostly used during full-throttle operation.
- Idle Speed Screw: This screw adjusts the engine's idle speed.
3. Start the Blower: With the blower turned off, turn the L screw clockwise until it gently seats (do not over-tighten). Then turn it counterclockwise 1 and a half turns. Turn the H screw clockwise until it gently seats, then turn it counterclockwise 1 turn.
4. Run the Blower: Start the blower and allow it to warm up for a few minutes. Ensure you have fresh and properly mixed fuel.
5. Adjust Low-Speed (L) Screw: While the engine is running, use a small flathead screwdriver to adjust the L screw. Turning the screw clockwise will lean out the fuel-air mixture, while turning it counterclockwise will enrich the mixture. Adjust the screw until the engine runs smoothly at a consistent low speed without hesitations or stalling.
6. Adjust High-Speed (H) Screw: With the blower still running, let it reach full throttle. Adjust the H screw in a similar manner as you did for the L screw. Turning it clockwise will lean out the mixture at high speeds, while counterclockwise turns will enrich it. Adjust until the engine accelerates smoothly and reaches maximum speed without bogging down or surging.
7. Adjust the Idle Speed: Finally, use the idle speed screw to fine-tune the engine's idling speed. Turn the screw clockwise to increase idle speed and counterclockwise to decrease it. Adjust until the engine idles smoothly without any signs of stalling.
8. Test the Blower: Test the blower at various speeds and throttle settings to ensure it operates smoothly, accelerates responsively, and idles consistently.
Remember that carburetor adjustments can be delicate and can vary based on environmental factors like temperature, altitude, and fuel quality. If you encounter difficulties or are uncertain about the process, consult the user manual for your specific Stihl BG55 blower, seek assistance from a qualified small engine mechanic, or contact an authorized Stihl dealer for further guidance.
