STIHL Fs 50 C Manual

FS 40, FS 40 C, FS 50, FS 50 C
English
29
Installing the Spark Plug
NScrew the spark plug into the 
cylinder.
NPress the spark plug boot with cap 
firmly on to the spark plug.
If the cap has become detached from 
the spark plug boot:NPush the cap on to the spark plug 
boot as far as stop.
If engine running behavior is 
unsatisfactory even though the air filter 
is clean and the carburetor is properly 
adjusted, the cause may be the muffler.
Have the muffler checked for 
contamination (carbonization) by...

FS 40, FS 40 C, FS 50, FS 50 C
English
30 To help prolong the wear life of the 
starter rope, observe the following 
points:
NPull the starter rope only in the 
direction specified.
NDo not pull the rope over the edge of 
the guide bushing.
NDo not pull out the rope more than 
specified.
NDo not allow the starter grip to snap 
back, guide it back into the housing 
slowly – see chapter on "Starting / 
Stopping the Engine."
Have a damaged starter rope replaced 
by your dealer before it breaks...

FS 40, FS 40 C, FS 50, FS 50 C
English
31 NHold the mowing head steady and 
rotate the cap (1) counterclockwise 
until it can be removed.
NPull the spool (2) out of the mowing 
head (3) and remove the remaining 
line.Assembling the mowing head
NFit the empty spool in the mowing 
head.
If the spring (4) has popped out,
Npush it into the spool (2) until it 
engages in position with an audible 
click.
NMount the mowing head – see 
"Mounting the Mowing Head".Winding line onto spool
NUse green-coded...

FS 40, FS 40 C, FS 50, FS 50 C
English
32 NHold the mowing head steady.
NRotate the spool counterclockwise 
until the shortest line is about 4 in 
(10 cm).
NIf necessary, cut the longer line to a 
length of about 4 in (10 cm).
The mowing head is now full.
STIHL AutoCut 5-2
Always check the mowing head for signs 
of wear before replacing the nylon line.
If there are signs of serious wear, 
replace the parts concerned or install a 
new mowing head.Preparations
NShut off the engine.
NPut the machine on the...

FS 40, FS 40 C, FS 50, FS 50 C
English
33 NStraighten out the nylon lines and 
wind them tightly on to the spool – 
one nylon line in each chamber.
NEngage the ends of the lines in the 
notches (2).
Assembling the mowing head
Check that the compression spring is 
installed (see "Mounting the Mowing 
Head").NThread the ends of the lines (6) 
through the sleeves (7) and push 
the spool (2) into the head so that it 
snaps into position.
The nylon lines must disengage from the 
notches (5) as the...

FS 40, FS 40 C, FS 50, FS 50 C
English
34
Maintenance and Care
The following intervals apply to normal operating conditions only. If your daily work-
ing time is longer or operating conditions are difficult (very dusty work area, etc.), 
shorten the specified intervals accordingly.
before starting work
after finishing work or daily
after each refueling stop
weekly
monthly
every 12 months
if problem
if damaged
if required
Complete machineVisual inspection (condition, leaks)XX
CleanX
Control handle Check...

FS 40, FS 40 C, FS 50, FS 50 C
English
35
Cutting attachmentVisual inspectionXX
ReplaceX
Check tightnessXX
Safety labels ReplaceX
1)STIHL recommends a STIHL servicing dealer.2)not in all versions, market-specific The following intervals apply to normal operating conditions only. If your daily work-
ing time is longer or operating conditions are difficult (very dusty work area, etc.), 
shorten the specified intervals accordingly.
before starting work
after finishing work or daily
after each refueling...

FS 40, FS 40 C, FS 50, FS 50 C
English
361Loop Handle
2Carrying Ring
3Momentary Stop Switch
4Throttle Trigger Lockout
5Throttle Trigger
6Carburetor Adjusting Screws
7Choke Lever
8Air Filter Cover
9Cap with Spark Plug Boot
10Machine Support
11Fuel Pump
12Fuel Filler Cap
13Fuel Tank
14Starter Grip
15Muffler with Spark Arresting Screen
16Mowing Head
17Line Lmiting Blade
18Deflector
19Drive Tube
#Serial Number
Main Parts
11
546BA009 KN
32
5
4
#
1
7
6
8
9
10
12
13
14
15
17
18
19
16 

FS 40, FS 40 C, FS 50, FS 50 C
English
37
Definitions
1 Loop Handle
For easy control of machine during 
cutting work.
2 Carrying Ring
Connects the unit to the harness.
3 Momentary Stop Switch
Switches the engine's ignition off 
and stops the engine. 
4 Throttle Trigger Lockout
Must be depressed before the 
throttle trigger can be activated.
5 Throttle Trigger
Controls the speed of the engine.
6 Carburetor Adjusting Screws
For tuning the carburetor.
7 Choke Lever
Eases engine starting by enriching...

FS 40, FS 40 C, FS 50, FS 50 C
English
38 FS 40, FS 40 C
FS 50, FS 50 C
Ignition System
Electronic magneto ignition
Fuel System
All position diaphragm carburetor with 
integral fuel pump
Weight
dry, without cutting attachment and 
deflector
Overall length
without cutting attachmentContact your STIHL dealer for 
information regarding special 
accessories that may be available for 
your product. Displacement: 1.66 cu. in. 
(27.2 cm
3)
Bore: 1.34 in (34 mm)
Stroke: 1.18 in. (30 mm)
Engine power to 
ISO...