Jonsered FC 2255 - Manual (Page 29)

MAINTENANCE
English – 29
Low speed jet L
Try to find the highest idling speed, turning the low speed
needle L clockwise respectively counter-clockwise. When
the highest speed has been found, turn the low speed
needle L 1/4 turn counter-clockwise.
CAUTION! If the cutting attachment rotates when the
engine is idling the idle adjustment screw T should be
turned anti-clockwise until the cutting attachment 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.
High speed jet H
The high speed jet H affects the engine power, speed,
temperature and fuel consumption. If the high speed jet H
is set too lean (screwed in too far) the engine speed will
be too high and cause engine damage. Do not let the
engine run at full speed for more than 10 seconds.
Setting procedure with a load (Trimmer head should
be used)
Ensure the length of the trimmer cord is correct, i.e.
exactly reaches the knife on the trimmer guard. Use either
3 mm or 3.3 mm diameter trimmer cord.
Apply full throttle and turn the high speed jet H very slowly
clockwise until the engine slows down. Then turn the high
speed jet H very slowly anticlockwise until the engine
starts to run unevenly. Now turn the high speed jet H
slowly clockwise a little way until the engine runs
smoothly.
CAUTION! For optimum adjustment of the carburettor,
contact a qualified dealer/service workshop that has a
revolution counter at their disposal.
Correctly adjusted carburetor
When the carburetor is correctly adjusted the machine will
accelerate without hesitation and burble a little at
maximum speed. It is also important that the cutting
attachment does not rotate at idle. If the low speed jet L is
set too lean it may cause starting difficulties and poor
acceleration. If the high speed jet H is set too lean it will
result in less power, less performance, poor acceleration
and/or 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.
Adjusting the start throttle speed
(BC2255)
The correct start throttle speed is set by means of an
adjuster on the rear of the handle next to the cable. Use
this screw (5 mm Allen screw) to increase or decrease the
start throttle speed.
!
WARNING! If the idle speed cannot be
adjusted so that the cutting attachment
stops, contact your dealer/service
workshop. Do not use the machine until
it has been correctly adjusted or
repaired.
H
4 mm