STIHL Fs 50 C Manual

FS 40, FS 40 C, FS 50, FS 50 C
English
19 Block the drive shaft.
NTo block the shaft, insert a suitable 
tool (12) through the holes (13) in 
the deflector and thrust plate – turn 
the thrust plate back and forth if 
necessary.STIHL FixCut 5-2
NSlip the thrust plate (2) over the 
shaft.
NPlace the mowing head on the 
thrust plate (2).
Collar (see arrow) must engage the 
mowing head's mounting hole.
NPush the thrust washer (3) over the 
shaft (1) so it is seated on the base.
NBlock the shaft – see...

FS 40, FS 40 C, FS 50, FS 50 C
English
20
Adjusting Nylon Line
STIHL AutoCut
NHold the rotating mowing head 
above the ground – tap it on the 
ground once – about 1.2 in. (3 cm) 
fresh line is advanced.
NThe blade (1) on the deflector (2) 
trims surplus line to the correct 
length – avoid tapping the mowing 
head more than once at a time.
Line feed operates only if both lines still 
h a v e  a  m i n i m u m  l e n g t h  o f   1 in. (2.5 cm).
If the mowing line is shorter than 1 in. 
(2.5 cm):
To reduce...

FS 40, FS 40 C, FS 50, FS 50 C
English
21 The idle speed and maximum speed of 
the engine change if you switch from a 
fuel with a certain ethanol content to 
another fuel with a much higher or lower 
ethanol content.
This problem can be avoided by always 
using fuel with the same ethanol 
content.
Use only STIHL two-stroke engine oil or 
equivalent high-quality two-stroke 
engine oils that are designed for use 
only in air cooled two-cycle engines.
W e  r e c o m m e n d  S T I H L  H P  U l t r a  2 -...

FS 40, FS 40 C, FS 50, FS 50 C
English
22 Toolless filler cap (with folding grip)
Threaded filler cap
Opening the toolless filler cap
NRaise the grip into an upright 
position.NTurn the cap counterclockwise 
(approx. 1/4 turn).
NRemove fuel filler cap.Refueling
Take care not to spill fuel while fueling 
and do not overfill the tank. STIHL 
recommends use of the STIHL filling 
system (special accessory).
Closing the toolless filler cap
With grip in an upright position:NInsert the cap – positioning marks...

FS 40, FS 40 C, FS 50, FS 50 C
English
23
Checking for proper closure
NThe lug on the grip must engage 
entirely in the recess (arrow), and 
the grip must lie completely flush 
with the top of the cap.
NGrip the cap and check for 
tightness.
NIf the cap can be moved, it is not 
properly installed.
Misalignment of the cap parts
NIf the cap does not drop fully into the 
opening when the positioning marks 
line up and/or if the cap does not 
tighten properly when twisted, the 
base of the cap may be rotated...

FS 40, FS 40 C, FS 50, FS 50 C
English
24
Controls
Version with loop handle
1Throttle trigger lockout
2Throttle trigger
3Momentary stop switch with Run 
and 0= Stop positions.
Function of momentary stop switch and 
ignition system
The momentary stop switch is normally 
in the Run position: Ignition is on in this 
position – the engine is ready to start 
and may be started. If the momentary 
stop switch is moved to the 0 position, 
the ignition is off. It is automatically 
switched on again after the...

FS 40, FS 40 C, FS 50, FS 50 C
English
25 NHold the starter grip with your right 
hand.
Models without Easy2Start
NPull the starter grip slowly until you 
feel it engage and then give it a brisk 
strong pull.
Models with Easy2Start
NPull the starter grip steadily.
Do not pull out the starter rope all the 
way – it might otherwise break.
NDo not let the starter grip snap back. 
Guide it slowly back into the housing 
so that the starter rope can rewind 
properly.
NContinue cranking until the engine...

FS 40, FS 40 C, FS 50, FS 50 C
English
26
During break-in period
A factory-new machine should not be 
run at high revs (full throttle off load) for 
the first three tank fillings. This avoids 
unnecessary high loads during the 
break-in period. As all moving parts 
have to bed in during the break-in 
period, the frictional resistances in the 
engine are greater during this period. 
The engine develops its maximum 
power after about 5 to 15 tank fillings.
During Operation
After a long period of full...

FS 40, FS 40 C, FS 50, FS 50 C
English
27 Exhaust emissions are controlled by the 
design of the fundamental engine 
parameters and components (e.g. 
carburation, ignition, timing and valve or 
port timing) without the addition of any 
major hardware.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 
make corrections with the adjusting 
screws within fine limits....

FS 40, FS 40 C, FS 50, FS 50 C
English
28 Cutting attachment rotates when engine 
is idling
NTurn the idle speed screw (LA) 
counterclockwise until the tool stops 
moving and then turn the screw 
another full turn in the same 
direction.
If the cutting tool continues to rotate 
when the engine is idling, have your 
machine checked and repaired by your 
servicing dealer.
Erratic idling behavior, engine stops 
even though setting of LA-screw has 
been corrected, poor acceleration
Idle setting is too lean...