MAINTENANCE

Fine adjustment

When the machine has been ”run-in” the carburettor should be finely adjusted. The fine adjustment should be carried out by a qualified person. First adjust the L-jet, then the idling screw T and then the H-jet.

The recommended engine speeds are as follows:

 

Max. fast idle speed, rpm

Idle speed, rpm

CS 2165

12500

2700

CS 2171

13500

2700

Conditions

Before any adjustments are made the air filter should be clean and the cylinder cover fitted. Adjusting the carburettor while a dirty air filter is in use will result in a leaner mixture next time the filter is cleaned. This can give rise to serious engine damage.

Carefully turn the L and H-jets clockwise as far as they will go. Now turn the jets one turn anti-clockwise. The carburettor is now set to H = 1 and L = 1.

Now start the machine according to the starting instructions and let it warm up for 10 minutes. CAUTION!

If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Place the machine on a flat surface so that the bar points away from you and so that the bar and chain do not come into contact with the surface or other objects.

Low speed jet L

Try to find the highest idle speed by turning the low speed jet L clockwise then anti-clockwise. When the highest speed has been found, turn the low speed jet L 1/4 turn anti-clockwise.

+ 1/4

L

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Fine adjustment of the idle speed T

Adjust the idle speed using the idle adjustment screw T, if it is necessary to readjust. First turn the idle adjustment screw T clockwise until the cutting attachment starts to rotate. Then turn the screw anticlockwise until the cutting attachment stops. The idle speed is correctly adjusted when the engine will run smoothly in every position. The idle speed should also be well below the speed at which the cutting attachment starts to rotate.

WARNING! Contact your servicing dealer, if

!the idle speed setting cannot be adjusted so that the chain stops. Do not use the chain saw until it has been properly adjusted or repaired.

High speed jet H

The high speed jet H influences the power and engine speed of the machine. If the high speed jet is set too rich (H-jet screwed in too far) the machine will over-rev and this will damage the engine. Run the machine at full throttle for about 10 seconds. Then turn the H-jet 1/4 turn anti-clockwise. Run the machine at full throttle for another 10 seconds or so and listen to the difference in the fast idle speed. Repeat this procedure with the H-jet turned a further 1/4 turn anti-clockwise.

H

You have now run the machine at settings of H =±0, H=+1/ 4, H=+1/2 relative to the basic settings. At full throttle the engine has sounded different for each setting. The H-jet is correctly adjusted when the machine burbles a little. If the machine ”screams” then the machine is set too lean. If the muffler emits a lot of smoke and the machine burbles a lot then the setting is too rich. Turn the H-jet clockwise until the setting sounds right

CAUTION! To ensure correct adjustment you should enlist a qualified mechanic who has access to a tachometer. The recommended maximum fast idle speed must not be exceeded.

Correctly adjusted carburettor

When the carburettor is correctly adjusted the machine accelerates without hesitation and 4-cycles a little at full throttle. It is also important that the chain does not rotate at idle. If the L-jet is set too lean it may cause starting difficulties and poor acceleration. If the H-jet is set too lean the machine will have less power, poor acceleration and could suffer damage to the engine.

If both the L and H jets are set too rich it will results in acceleration problems or too low a working speed.

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Jonsered CS 2171WH manual Recommended engine speeds are as follows, Idle speed, rpm