Jonsered CS 2141 Workshop Manual

English – 43
Repair instructions
Fine adjustment of idling speed T
• The idling speed is adjusted using the screw
marked T.
• If adjustment is necessary, screw in the idling
screw T until the chain starts to turn. Then screw it
out until the chain stops moving.
• The idling speed is correctly set when the engine
runs smoothly in all positions and there is a clear
margin to the speed at which the chain starts to
move.
High speed jet H
• The high speed jet H infl uences the saw power
output and engine speed. If the H jet is set too
weak the saw will over-rev, which could cause
engine damage.
• Run the saw at full throttle for about 10 seconds.
H=1.
• Then screw out the H screw 1/4 turn. H=1 1/4.
• Run the saw again at full throttle for about 10
seconds and listen to the difference in the engine
note. Repeat this procedure again with the H
screw screwed out another 1/4 turn. H=1 1/2.
• You have now run the saw at settings H ± 0, H =
+1/4 and H = +1/2 from the factory setting. At full
throttle the engine will sound different at each set-
ting.
• The H screw is correctly adjusted when the saw
“burbles” a little at full throttle without any load.
• If there is a lot of smoke from the silencer and the
saw does not run smoothly then the setting is too
rich.
• Screw in the H screw to the setting that sounds
right.
NOTE!
For optimum adjustment, a tachometer
should be used. The recommended maxi-
mum speed should not be exceeded.
Carburettor – correct adjustment
• When the carburettor is correctly adjusted the
saw should accelerate without hesitation and the
engine will burble a little at full throttle without any
load.
• The chain must not turn when idling.
• If the L screw is set too weak this can make the
saw diffi cult to start and cause poor acceleration.
• If the H screw is set too weak the saw will produce
less power, poor acceleration and there is a risk of
engine damage.
• If either the L or H screws are set too rich it will
cause acceleration problems or too low working
speed.
Fine adjustment
Once the chainsaw is “run in” the carburettor
should be readjusted. First adjust the L jet screw,
then the idling screw T and fi nally the H jet screw.
The recommended engine speeds are as follows:
Model Max revs Idle revs
CS 2141 12,500 rpm 2,700 rpm
CS 2145 12,500 rpm 2,700 rpm
CS 2147 14,200 rpm 2,700 rpm
CS 2149 13,000 rpm 2,700 rpm
CS 2150 13,000 rpm 2,700 rpm
CS 2152 13,000 rpm 2,700 rpm
CS 2156 14,000 rpm 2,700 rpm
CS 2159 13,500 rpm 2,700 rpm
NOTE!
If the chain turns at idling speed, the T
screw should be turned anti-clockwise
until the chain stops.
Basic requirements
• Before making any adjustments the air fi lter
should be clean and the cylinder cover should
be in place. If the carburettor is adjusted with a
dirty air fi lter, the mixture will be too weak next
time the air fi lter is cleaned. This can cause seri-
ous engine damage.
• Carefully screw in the L and H jets fully, then
back them off 1 turn. The carburettor now has
the settings H = 1 and L = 1.
• Start the chainsaw and allow it to warm up for
10 minutes.
• Place the saw on a fl at surface so that the guide
bar is pointing away from you and the guide bar
and chain are not touching the surface.
Low speed jet L
• Find the highest idling speed by slowly screwing
the L screw in and then out again.
• When the highest speed has been found, screw
out the L screw 1/8 - 1/4 turn.
If it is not possible to check the maximum speed
with a tachometer then the H jet should not be set
to a weaker mixture than the basic factory setting.
The recommended maximum speed must not
be exceeded.

Jonsered CS 2141 Specifications

General

Brand	Jonsered
Model	CS 2141
Category	Chainsaw
Language	English