18 – English
MAINTENANCE
Fine adjustment of the idle speed T
Adjust the idle speed with the idle adjustment screw T, if
adjustment is necessary. First turn the idle adjustment screw
T clockwise until the blades start to move. Then turn the idle
adjustment screw T anticlockwise until the blades stop. The
idle speed is correctly adjusted when the engine runs
smoothly in every position. There should also be a clear
margin to the speed at which the blades start to move.
The blades must also remain stationary when the choke
control is in the start throttle position.
IMPORTANT! 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.
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.
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.
Note that the engine should not be under load when you
adjust the high speed jet H. You should therefore remove the
cutting attachment, nut, support flange and drive disc before
adjusting the high speed jet H. The high speed jet H is
adjusted correctly when the machine burbles a little. If the
machine races then the setting is too lean. If the engine
produces a lot of smoke and burbles a lot then the setting is
too rich.
CAUTION! For optimum adjustment of the carburettor,
contact a qualified dealer/service workshop that has a
revolution counter at their disposal.
Correctly adjusted carburettor
When the carburettor is correctly adjusted the machine
accelerates without hesitation and burbles a little at maximum
speed. It is also important that the blades do not move when
the engine is idling or when the choke control is in the start
position. 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.
Muffler
CAUTION! Some mufflers are fitted with a catalytic
converter. See chapter on Technical data to see whether your
machine is fitted with a catalytic converter.
The muffler is designed to reduce the noise level and to direct
the exhaust gases away from the operator. The exhaust
gases are hot and can contain sparks, which may cause fire
if directed against dry and combustible material.
Some mufflers are equipped with a special spark arrestor
mesh. If your machine has this type of muffler, you should
clean the mesh at least once a week. This is best done with a
wire brush.
On mufflers without a catalytic converter the mesh should be
cleaned weekly, or replaced if necessary. On mufflers fitted
with a catalytic converter the mesh should be checked, and if
necessary cleaned, monthly. If the mesh is damaged it
should be replaced. If the mesh is frequently blocked, this
can be a sign that the performance of the catalytic converter
is impaired. Contact your dealer to inspect the muffler. A
blocked mesh will cause the machine to overheat and result
in damage to the cylinder and piston. See also instructions
under the heading Maintenance.
CAUTION! Never use a machine with a defective muffler.
H
!
WARNING! Mufflers fitted with catalytic
converters get very hot during use and
remain so for some time after stopping. This
also applies at idle speed. Contact can result
in burns to the skin. Remember the risk of
fire!
