Chainsaw carburator - Echo 370

Echo manual description.
CARBURATOR ADJUSTMENT
Every Unit is run at the factory and the carburetor is set in compliance with Emission regulations. In addition the carburetor is equipped with a high speed (H) and low speed (L) needle adjustment limiters that prevent settings outside acceptable limits.
1. Before adjusting carburetor clean or replace air filter and muffler, �Spark Arrestor Screen�
2. Make sure the bar and chain is properly adjusted.
3. Start engine and bring to operating temperature.
4. Stop Engine. Turn �H� speed needle counter clockwise (CCW) to stop. Turn �L� speed needle midway between full clockwise (CW) stop and full CCW.
5. Idle speed adjustment. Start engine, turn �idle� speed adjustment screw CW until saw chain begins to turn, then turn screw CCW until saw chain stops turning. Turn screw an additional � turn.
6. Accelerate to full throttle for 2-3 seconds to clear any excess fuel in engine, then return to idle. Accelerate engine to full throttle to check for smooth transition from idle to high speed. If engine hesitates turn �L� needle CCW 1/8 turn and repeat acceleration.
Continue adjustment until smooth acceleration results.
7. Check idle speed and reset if necessary as described in item 5. If a tachometer is available it should be set between 2400 � 2900 rpm.