Adjusting The Carburetor - Stihl HS 81 Instruction Manual

English
Position filter cover against the left
N
side of the filter housing and swing it
to the right – the two lugs (arrows)
must engage the filter cover
openings.
Insert the screw and tighten it down
N
firmly.
14

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.
Preparations
Shut off the engine.
N
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.
Inspect cutting blades and clean if
N
necessary (clean, move freely, not
warped).
Different Standard Settings
Different carburetors are installed at the
factory. A different standard setting is
necessary for each of these carburetors.
Standard setting A
High speed screw (H) = 3/4
–
Low speed screw (L) = 1
–
Standard setting B
High speed screw (H) = 3/4
–
Low speed screw (L) = 3/4
–
Determine the required standard
N
setting as follows: Turn the low
speed screw (L) carefully clockwise
as far as stop, then turn it
counterclockwise.
Is range of adjustment more than 1 turn?
Continue with "Standard setting A"
N
Is range of adjustment less than 1 turn?
Continue with "Standard setting B"
N
Standard setting A
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 until it is against
its seat, then turn it back 1 full turn
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC