Stihl FS 100 RX Product Instruction Manual - Page 28

Adjusting the Carburetor - air filter

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English Adjusting the Carburetor The carburetor comes from the factory with a standard setting. This setting provides an optimum fuel-air mixture under most operating conditions. With this carburetor it is only possible to adjust the high speed and low speed screws within fine limits. Standard Setting N Shut off the engine. N Mount approved cutting tool or attachment. N Check the air filter and clean or replace as necessary. N Check that the throttle cable is properly adjusted - readjust if necessary - see chapter on "Adjusting the Throttle Cable". N Check the spark arresting screen and clean or replace as necessary. N Carefully turn both adjusting screws counterclockwise as far as stop: - The high speed screw (H) is 3/4 turn open. - The low speed screw (H) is 3/4 turn open. N Start and warm up the engine. N Adjust idle speed with the idle speed screw (LA) so that the cutting attachment does not move. Fine Tuning 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, sea level or after changing the working tool. 249BA051 KN Rule of thumb: Turn the high speed screw (H) about one quarter of a turn for every 3300 ft (1000 m) change in altitude. Conditions for adjustment N Carry out the standard setting without disturbing the high speed screw (H). N Warm up the engine for about 3 minutes. N Open the throttle wide. At high altitude N Turn the high speed screw (H) clockwise (leaner), no further than stop, until there is no further noticeable increase in engine speed. At sea level N Turn the high speed screw (H) counterclockwise (richer), no further than stop, until there is no further noticeable increase in engine speed. It is possible that maximum engine speed may be reached with the standard setting in each case. Readjust idle It is usually necessary to change the setting of the idle speed screw (LA) after every correction to the low speed screw (L). N Warm up the engine for about 3 minutes. 26 FS 100 RX

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FS 100 RX
English
26
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
adjust the high speed and low speed
screws within fine limits.
Standard Setting
N
Shut off the engine.
N
Mount approved cutting tool or
attachment.
N
Check the air filter and clean or
replace as necessary.
N
Check that the throttle cable is
properly adjusted – readjust if
necessary – see chapter on
"Adjusting the Throttle Cable".
N
Check the spark arresting screen
and clean or replace as necessary.
N
Carefully turn both adjusting screws
counterclockwise as far as stop:
–
The high speed screw
(H) is 3/4 turn
open.
–
The low speed screw (H) is 3/4 turn
open.
N
Start and warm up the engine.
N
Adjust idle speed with the idle speed
screw (LA) so that the cutting
attachment does not move.
Fine Tuning
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, sea level or
after changing the working tool.
Rule of thumb:
Turn the high speed screw (H) about
one quarter of a turn for every 3300 ft
(1000 m) change in altitude.
Conditions for adjustment
N
Carry out the standard setting
without disturbing the high speed
screw (H).
N
Warm up the engine for about 3
minutes.
N
Open the throttle wide.
At high altitude
N
Turn the high speed screw (H)
clockwise (leaner), no further than
stop, until there is no further
noticeable increase in engine
speed.
At sea level
N
Turn the high speed screw (H)
counterclockwise (richer), no further
than stop, until there is no further
noticeable increase in engine
speed.
It is possible that maximum engine
speed may be reached with the standard
setting in each case.
Readjust idle
It is usually necessary to change the
setting of the idle speed screw
(LA) after
every correction to the low speed
screw (L).
N
Warm up the engine for about 3
minutes.
Adjusting the Carburetor
249BA051 KN