Stihl FS 50 - 8.5 Adjusting the Carburetor; 8.5.1 Basic Setting

54 Series 4144 Components FC, FS, KM
High speed screw (H)
Always use a new limiter cap and
position it so that the long part of the
cap butts against the top of the stop
(arrow).
: Push the limiter cap (1) on to the
low speed screw as far as the first
detent – the limiter cap is thus
prepared for final installation.
– Carry out basic setting, b 8.5.1
8.5 Adjusting the Carburetor
8.5.1 Basic Setting
The basic setting is necessary only
if the high speed screw (H) or low
speed screw (L) has to be replaced,
the limiter caps have been removed
or after cleaning and adjusting the
carburetor from scratch.
– Pre-install the new limiter caps on
the high speed and low speed
screws, b 8.4.5
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High speed and low speed screws
can now be adjusted through the
pre-installed limiter caps.
Starting with the low speed and high
speed screws against their seats,
turn them counterclockwise.
: Turn the high speed screw H (1)
one and one half turns Turn the
low speed screw L (2) one full
turn.
This completes the basic setting of
the high speed screw (H) and the
low speed screw (L).
– Mount the deflector and cutting
tool (mowing head), see
instruction manual
– the cutting tool must turn freely,
clean it if necessary.
– Inspect the spark arresting
screen (if fitted) and clean or
replace if necessary. b 5.8
The carburetor must be installed.
– Check the air filter and clean or
replace if necessary, b 8.1
– Allow engine to warm up.
Setting disk 5910 893 6600 may
be fitted on the screwdriver
5910 890 2305 to simplify
adjustments.
0
14
12
10
8
6
4
2
0
14
12
10
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: Push screwdriver (1)
5910 890 2305 into the adjusting
screws (arrow).
Adjust idle speed with a tachometer.
Adjust specified engine speeds
within tolerance of ± 200 rpm.
1. Adjust engine speed with
idle speed screw (LA)
to 3,000 rpm.
2. Turn the low speed screw (L)
clockwise or counterclockwise
to obtain the maximum engine
speed.
If this speed is higher than
3,700 rpm, abort the procedure and
start again with step 1.
3. Use the idle speed screw (LA)
to set the engine speed again to
3,000 rpm.
4. Set the engine speed to
2,800 rpm with the low speed
screw (L)
.
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