Adjusting the carburetor chainsaw ensures efficient operation of the tool at full power with economical fuel consumption. The adjustment must be made with clean fuel and air filter. For a more significant number of carburetors, calibration is carried out with three screws: for maximum and minimum turns and adjustment of idling.
The screws H and L regulate the ratio of the mixture of gasoline and air determined by the opening of the throttle valve of the carburetor. When the screws are unscrewed, the mixture is enriched, and the turnovers fall accordingly while tightening the mixture is depleted. the turnovers grow.
The designation H refers to the maximum rotation screw driving the main jet, L refers to the minimum rotation screw driving the idling jet. Using screw S, precise adjustment of the idling speed is carried out. Sometimes, to simplify adjustment, the number of available carburetor adjustment screws is reduced.
The setting of the carburetor of the chainsaw is divided into two stages. the basic one (factory settings), carried out with the engine off, and the final one, performed with the engine running warm. The exact value of the angles of rotation should be taken from the operating instructions for a specific chainsaw. Failure to follow the manufacturer’s instructions may result in engine damage.
Basic carburetor adjustment.
The adjusting screws of the maximum H and minimum L turns are slowly turned clockwise until it stops, then turned back two turns, other settings are also possible
Check and adjustment of idling.
We are looking for the highest idle speed; for this, we slowly turn the screw L in different directions. After finding the position of the highest revolutions of the engine, you must turn the screw L 1/4 of a turn counterclockwise. If the chain rotates at idle, screw T or (S) should be turned by simply turning it clockwise until it stops.
Check and adjust the maximum speed.
The change in the maximum number of revolutions is carried out with the screw H. When it is turned (clockwise), the turns increase, and when turned, they turn down. Chainsaw engines have the highest rotational speed of 11500 r / min. up to 15,000 rpm Higher speed does not provide ignition; in addition, it becomes dangerous for the engine. Interruptions can determine limit revolutions in the fire. If they do, turn screw H slightly counterclockwise.
If the engine is not tested for acceleration and maximum speed, the adjustment of the chainsaw cannot be considered complete.
When the gas trigger is gently pressed, the engine should confidently and quickly pick up speed from idle to maximum (from 2800 rev. to 11500-15000 rev., Depending on the unit). If the revolutions are slower, with a delay, screw L must be slowly turned counterclockwise, but not more than 1/8 of a turn.
After adjusting the acceleration and maximum speed, the saw should be rechecked at idle. the engine should work stably, the chain should not move. The setting of the chainsaw should be repeated if this condition is not fulfilled but except the stage of necessary adjustment.