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13 Adjusting the Carburetor
13.1
General Information
The carburetor comes from the factory with a
standard setting.
This setting provides an optimum fuel-air mixture
under most operating conditions.
13.2
Preparations
► Shut off the engine.
► Mount the attachment.
► Check the air filter and replace if necessary.
► Check that the throttle cable is properly adjus‐
ted – readjust if necessary – see chapter on
"Adjusting the Throttle Cable".
13.3
Carry out the standard setting.
–
High speed screw (H) = 3/4
–
Low speed screw (L) = 3/4
255BA006 KN
H
L
► Turn high speed screw (H) counterclockwise
as far as stop (no more than 3/4 turn).
► Turn the low speed screw (L) carefully clock‐
wise as far as stop, then turn it back 3/4 turn.
13.4
Adjust idle speed
► Carry out the standard setting.
► Start and warm up the engine.
255BA007 KN
LA
13.4.1
Engine stops while idling
► Turn the idle speed screw (LA) clockwise until
the engine runs smoothly – the attachment
must not run.
13.4.2
Attachment runs when engine is idling
► Turn the idle speed screw (LA) counterclock‐
wise until the attachment stops moving and
then turn the screw another 1/2 to 1 full turn in
the same direction.
WARNING
If the attachment continues to run when the
engine is idling, have your machine checked and
repaired by your servicing dealer.
13.4.3
Erratic idling behavior, poor accelera‐
tion (despite correction to setting of LA
screw).
Idle setting is too lean
► Turn the low speed screw (L) counterclock‐
wise, no further than stop, until the engine
runs and accelerates smoothly.
13.4.4
Erratic idling behavior
Idle setting is too rich
► Turn the low speed screw (L) clockwise, no
further than stop, until the engine runs and
accelerates smoothly.
It is usually necessary to change the setting of
the idle speed screw (LA) after every correction
to the low speed screw (L).
13.5
Fine Tuning for Operation at
High Altitude
A slight correction of the setting may be neces‐
sary if engine does not run satisfactorily:
► Carry out the standard setting.
► Warm up the engine.
► Turn high speed screw (H) slightly clockwise
(leaner) – no further than stop.
NOTICE
After returning from high altitude, reset the car‐
buretor to the standard setting.
If the setting is too lean there is a risk of engine
damage due to insufficient lubrication and over‐
heating.
14 Spark Plug
► If the engine is down on power, difficult to start
or runs poorly at idle speed, first check the
spark plug.
13 Adjusting the Carburetor
English
0458-516-0121-B
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