filter is in use will result in a leaner mixture when the filter is finally
cleaned. This can give rise to serious engine damage.
Functioning, Basic setting, Final settingY Carefully turn the L and H-jets clockwise to the bottom. Now turn the
jets one turn anti-clockwise. The carburettor is now set to H = 1 and
WARNING! Do not start the saw without the bar,L = 1.
chain and clutch cover (chain brake) assembled. IfY Now start the saw according to the starting instructions and run it
!you do, the clutch might come loose and causewarm for 10 minutes.
severe injuries.NOTE! If the chain rotates the T screw should be turned anti-
clockwise until the chain stops.
Y Place the saw 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
Y The carburettor governs the engine speed via the throttle. Air/fuel
surface or other objects.
are mixed in the carburettor. The air/fuel mixture is adjustable. To
take advantage of the sawOs maximum output the setting must be
Low speed needle L
Y Adjusting the carburettor means the engine is adapted to localTry to find the highest idling
operating conditions, e.g. climate, altitude, petrol and the type of 2-speed, turning the low speed
stroke oil used.needle L clockwise respectively
counter-clockwise. When the
highest speed has been found,
turn the low speed needle L 1/4
Y The carburettor has three
NOTE! If the chain rotates in the
L = Low speed jet.
H = High speed jet.idling position, turn the idlingL
T = Adjustment screw for idling.speed screw counter-clockwise
until the chain stops.
Y The fuel quantity required in relation to the air flow, provided byFinal setting of the idling speed T
opening the throttle, is adjusted by the L and H-jets. If they areAdjust the idling speed with the screw T. If it is necessary to re-adjust,
screwed clockwise the air/fuel ratio becomes leaner (less fuel) and iffirst turn the idle speed adjusting screw T clockwise, until the chain
they are turned anti-clockwise the ratio becomes richer (more fuel).starts to rotate. Then turn, counter-clockwise until the chain stops. A
A leaner mixture gives a higher engine speed and a richer mixturecorrectly adjusted idle speed setting occurs when the engine runs
give a lower engine speed.smoothly in every position. It should also be good margin to the rpm
Y The T screw regulates the idling speed. If the screw T is turnedwhen the chain starts to rotate.
clockwise this gives a higher idling speed; anti-clockwise a lower
idling speed.Contact your servicing dealer, if the idle speed
setting cannot be adjusted so that the chain stops.
!Do not use the saw until it has been properly
Basic setting and running in
adjusted or repaired.
The carburettor is adjusted to a basic setting when the saw is tested at
254XP:The basic setting is: H = 1 / turns respectiveHigh speed needle H
L = 1 /4 turns.The high speed needle H
257:The basic setting is: H = 1 turn respective L = 1 turn.
influences the power of the saw.
262XP:The basic setting is: H = 1 turn respective L = 1 turn.
A too lean adjusted high speed
To provide the engineOs components with a good level of
needle H (high speed needle H
lubrication (running in) the carburettor should be set for a richer
closed too much) gives overrevs
fuel mixture for the first 3-4 hours of operating. To obtain thisand damages the engine. Let the
adjust the overspeed 600-700 rpm under the recommended max.
saw run at full speed for about 10
seconds. Thereafter, turn the high
If you do not have the possibility to check the overspeed using a
speed needle H 1/4 turn counter-H
tachometer the H-jet should not be set for a leaner mixture than that
stated for the basic setting.
Let the saw run again at full
The recommended overspeed should not be exceeded.
speed for about 10 seconds and note the difference of the engine-
NOTE! If the chain rotates while idling the T screw should be adjusted
sound. Repeat this procedure with the high speed needle H turned 1/4
anti-clockwise until it stops.
turn more counter-clockwise. The saw has now been tested with the
following settings: H=0, H=+1/4, H=+1/2 from basic adjustment. At full
Fine adjustmentspeed the engine has produced a different sound for each setting. The
Y When the saw has been Ãôrun-inÃô the carburettor should be finelyhigh speed needle H is correctly set when the saw Ãô4-cyclesÃô a little. If
adjusted. The fine adjustment should be carried out by qualifiedthe saw ÃôwhistlesÃô the setting is too lean. If there is too much exhaust
person. First adjust the L-jet, then the idling screw T and then the H-gas at the same time as the saw Ãô4-cyclesÃô much, the setting is too
jet. The following engine speed applies:rich. Turn the high speed needle H until the setting sounds correct.
Max. overspeedIdling speedNOTE! For optimum setting of the carburettor, contact a qualified
254XP:13 800 rpm2 500 rpmservicing dealer who has a revolution counter at his disposal. The
257:13 500 rpm2 500 rpmmaximum speed recommended must not be exceeded.
262XP:13 500 rpm2 500 rpm
Correctly adjusted carburettor
Changing the type of fuelA correctly adjusted carburettor means that the saw accelerates
Fine tuning may be required if the chain saw, after changing the type ofwithout hesitation and the saw 4-cycles a little at max speed.
fuel, performs differently with regard to starting, acceleration, max.Furthermore, the chain must not rotate at idling. A too lean adjusted
speed, etc.low speed needle L may cause starting difficulties and bad accelera-
tion. A too lean adjusted high speed needle H gives lower power=less
capacity, bad acceleration and/or damage to the engine.
A too rich adjustment of the two speed needles L and H gives accele-
Y Before any adjustments are made the air filter should be clean and
ration problems or too low working speed.
the cylinder cowling fitted. Adjusting the carburettor while a dirty air
English ÄÉ 29