CS38 / CS41 SELECT Chainsaw
25
Original Instructions Version July 16
CS38-41_130716
Adjusting the Carburettor
The carburettor has been factory adjusted, but may require fine tuning due to a change in operating
conditions. Before adjusting the carburettor, make sure that the provided air/fuel filters are clean
and the fuel properly mixed.
When adjusting, take the following steps:
Stop the engine and screw in both the H and L needles until they stop. Never force them. Then set
them back the initial number of turns as shown below.
H needle: 2 +or- ¼
L needle: 2 +or- ¼
1.
Start the engine and allow it to warm up at half-throttle.
2.
Turn the L needle (2) slowly to find a position where
idling speed is at maximum, then set the needle back
a quarter (1/4) turn counter clockwise.
3.
Turn the idle adjusting screw T (1) counter clockwise so
that the saw chain does not turn. If the idling speed is
too slow, turn the screw clockwise.
4
.
To verify the low speed you should be able to pull the
throttle in all the way and the engine should not die,
if it tries to die, open the L jet (2) slightly and re-adjust
idle if necessary.
5.
Set the engine to full throttle, the H jet (3) is turned clockwise to reduce fuel, as the fuel
mixture is leaned out, the saw will run faster until it sounds as if it is screaming, at this
point, turn the high speed screw counter clockwise by quarter (1/4) turn to allow more
fuel in. A 2-cycle engine relies on the fuel mixture to cool the engine; a lean engine will
run fast but can overheat and may cause severe damage to the engine.
The carb mixture adjustment needs special tools and should only be adjusted by a
dealer or professional as incorrect mixture adjustment can damage the engine and will
invalidate the warranty.
