Return a type A carburetor to its factory setting by turning the “H” screw counterclockwise until it stops, turning the “L” screw clockwise until it is seated, then backing it off one full turn.
How do you calibrate a Stihl M Tronic?
Start the machine and run it in the ▲ Cold start position for at least 90 seconds. Do not touch the throttle or accelerate the saw during this time. After 90 seconds, switch off the machine. Your machine is now re-calibrated and ready for operation.
What does L and H mean on a carburetor?
The letters on the screws represent High (H), Low (L) and Idle (T). The H screw regulates the Air/Fuel mix during high RPMs, while the L Screw does the same during low RPMs. The T screw regulates how much fuel is sent to the carburettor while idling until the throttle is pressed.
