Stihl HL 75 Assembling, Safety Precautions, Operating Instructions, Maintenance page 24

Standard Setting
H L
3 / 4 1
LA
: Shut off the engine.
:
Inspect the cutting blades and clean
if necessary (they must be clean,
move freely and not be warped).
:
Check the air filter and install a new
one if necessary.
:
Check spark arresting screen* and
clean or replace as necessary.
: Turn high speed screw (H)
counterclockwise (max.
far as stop.
:
Carefully screw the low speed
screw (L) clockwise down onto its
seat. Then open it one full turn
counterclockwise.
:
Start and warm up the engine.
:
Adjust idle speed with the idle speed
screw (LA) so that the cutting
blades do not run.
* see "Guide to Using this Manual"
HL 75, HL 75 K
Adjusting Idle Speed
Engine stops while idling
:
Turn idle speed screw (LA) slowly
clockwise until the engine runs
smoothly – the cutting blades must
not run.
Cutting blades run when engine is
idling
:
Turn idle speed screw (LA) slowly
counterclockwise until cutting
3
/ turn) as
4 blades stop running and then turn
the screw about another
turn in the same direction.
Erratic idling behavior, poor
acceleration
Idle setting too lean:
:
Turn low speed screw (L)
counterclockwise (about
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).
Fine Tuning for Operation at
High Altitude
H L
3 / 4 1
LA
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude:
:
:
:
1
/ to 1
2
It is usually necessary to change the
setting of the idle speed screw (LA)
after every correction to the low speed
1
/ turn)
screw (L).
4
English / USA
H L
3 / 4 1
LA
Check standard setting.
Allow the engine to warm up.
Turn high speed screw (H) and low
speed screw (L) clockwise (leaner).
To avoid the risk of engine damage,
do not make the mixture too lean as
this will otherwise cause the engine
to over-rev.
23