Adjusting The Carburetor - Stihl HS 46 Instruction Manual

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Adjusting the Carburetor

General Information
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
Standard Setting
Shut off the engine.
N
Inspect cutting blades and clean if
N
necessary (clean, move freely, not
warped).
Check the air filter and clean or
N
replace if necessary.
Check the spark arresting screen
N
(not in all models, country-specific)
in the muffler and clean or replace if
necessary.
L H
LA
Turn high speed screw (H)
N
counterclockwise as far as stop (no
more than 3/4 turn).
Turn the low speed screw (L)
N
carefully clockwise as far as stop,
then turn it back 3/4 turn.
18
Adjusting Idle Speed
Carry out the standard setting.
N
Start and warm up the engine.
N
Engine stops while idling
Turn the idle speed screw (LA)
N
clockwise until the cutting blades
begin to run – then back it off
about 1 full turn.
Cutting blades run when engine is idling
Turn the idle speed screw (LA)
N
counterclockwise until the cutting
blades stop moving – then turn it
another 1 full turn in the same
direction.
WARNING
If the cutting blades continue moving
when the engine is idling, have your
hedge trimmer checked and repaired by
your servicing dealer.
Erratic idling behavior, poor acceleration
(despite correction to setting of LA
screw).
Idle setting is too lean
Rotate the low speed screw (L)
N
about 1/4 turn counterclockwise, no
further than stop, until the engine
runs and accelerates smoothly.
Machine stops when it is swung at idle
speed
Idle setting is too rich
Rotate the low speed screw (L)
N
about 1/4 turn clockwise until the
engine idles smoothly.
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
Fine Tuning for Operation at High
Altitude
A slight correction of the setting may be
necessary if engine does not run
satisfactorily:
Carry out the standard setting.
N
Warm up the engine.
N
Turn high speed screw (H) slightly
N
clockwise (leaner) – no further than
stop.
NOTICE
After returning from high altitude, reset
the carburetor to the standard setting.
If the setting is too lean there is a risk of
engine damage due to insufficient
lubrication and overheating.
HS 46, HS 46 C, HS 56 C