STIHL Fs 40 C Owners Manual

							FS 40, FS 40 C, FS 50, FS 50 C
English
29 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 nylon line with a 
diameter of 2.0 mm (0.08 in).
NCut two 2 m (6ft 6in) lengths of 
nylon line from the reel (special 
accessory).
NRotate the spool (2) 
counterclockwise until the two arrow 
points are in alignment.
NPush the straight end of each line 
through one sleeve (5) in the 
mowing head (3) until you feel a 
noticeable resistance – and then 
continue pushing as far as stop.
Schnur/LINE  1
681BA021 KN
1
2
3
Schnur/LINE  1
681BA022 KN
24
Schnur/LINE  2
681BA023 KN
5
Schnur/LINE  13
32 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
30 NHold the mowing head steady.
NRotate the spool counterclockwise 
until the shortest line is about 10 cm 
(4 in).
NIf necessary, cut the longer line to a 
length of about 10 cm (4 in).
The mowing head is now full.
STIHL AutoCut 5-2
Removing remaining nylon line
NOpen the mowing head – hold it 
steady with one hand and turn the 
cap (1) counterclockwise.
NDisengage the spool (2), take it out 
of the mowing head and remove the 
remaining line.
Winding line onto spool
A prewound spool (special accessory) 
may be used as an alternative to the 
following procedure.NUse green-coded nylon line with a 
diameter of 2.0 mm (0.08 in).
NCut two 3 m (9ft 9in) lengths of 
nylon line from the reel (special 
accessory).
NInsert the ends of each line (3) in the 
holes (4) in the spool.
NBend the ends of the lines over the 
edge of the holes to form a hook.
681BA024 KN
Schnur/LINE  2
Schnur/LINE  1
681BA008 KN
1
2
681BA009 KN
4
3
3 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
31 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
NOTICE
Check that the 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 spool is pushed into 
position.
NPull out the ends of the lines as far 
as stop.
NMount the mowing head on the 
machine.
Replacing Cutting Blades
STIHL PolyCut
Always check the mowing head for signs 
of wear before installing new cutting 
blades.
WARNING
If there are signs of serious wear, 
replace the complete mowing head.
The thermoplastic cutting blades are 
referred to as "blades" in the following.
The mowing head is supplied with 
illustrated instructions for replacing the 
blades. Keep the instructions for the 
mowing head in a safe place.
WARNING
To reduce the risk of injury, always shut 
off the engine before installing the 
blades.
NRemove the mowing head.
NReplace blades as shown in the 
illustrated instructions.
NMount the mowing head on the 
machine.
681BA010 KN
5
5
7
681BA011 KN
2
6
6 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
32
Spark arresting screen in muffler
NIf the engine is down on power, 
check the spark arresting screen in 
the muffler.
STIHL recommends that you have 
servicing and repair work carried out 
exclusively by an authorized STIHL 
servicing dealer.
Inspections and Maintenance 
by Dealer 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
33
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
as required
Complete machineVisual inspection (condition, leaks)XX
CleanX
Control handle Check operationXX
Air filterCleanXX
ReplaceX
Manual fuel pump (if fitted)CheckX
Have repaired by servicing dealer
1)X
Pickup body in fuel tankCheckX
ReplaceXXX
Fuel tank CleanXX
CarburetorCheck idle adjustment – the cutting 
attachment must not rotateXX
Readjust idleX
Spark plugReadjust electrode gapX
Replace after every 100 operating hours
Cooling inletsVisual inspectionX
CleanX
Spark arresting screen in mufflerHave checked by servicing dealer
1)X
Have cleaned or replaced by servicing 
dealer
1)XX
All accessible screws and nuts (not adjust-
ing screws)RetightenX 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
34
Cutting attachmentVisual inspectionXX
ReplaceX
Check tightnessXX
Safety labels ReplaceX
1)STIHL recommends an authorized STIHL servicing dealer. 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
as required 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
35 1Loop Handle
2Carrying Ring
3Stop Switch
4Throttle Trigger Lockout
5Throttle Trigger
6Carburetor Adjusting Screws
7Choke Lever
8Air Filter Cover
9Spark Plug Boot
10Machine Support
11Manual Fuel 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
14
19
18
17
16
1513
12
11
87
6
1
234
510#
546BA015 KN
9 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
36
Definitions
1 Loop Handle
For easy control of machine during 
cutting work.
2 Carrying Ring
Connects the unit to the harness.
3 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 
mixture.
8 Air Filter Cover
Covers and protects the air filter 
element.
9 Spark Plug Boot
Connects the spark plug with the 
ignition lead.
10 Machine Support
For resting machine on the ground.
11 Manual Fuel Pump
Provides additional fuel feed for a 
cold start.
12 Fuel Filler Cap
For closing the fuel tank.
13 Fuel Tank
For fuel and oil mixture.14 Starter Grip
The grip of the pull starter, for 
starting the engine.
15 Muffler with Spark Arresting Screen
Muffler reduces exhaust noises and 
diverts exhaust gases away from 
operator.
Spark arresting screen is designed 
to reduce the risk of fire.
16 Mowing Head
The cutting attachment, i.e. mowing 
head, for different purposes.
17 Line Limiting Blade
Metal blade on the deflector which 
keeps the line of the mowing head 
at the proper length.
18 Deflector
Designed to reduce the risk of injury 
from foreign objects flung 
backwards toward the operator by 
the cutting attachment and from 
contact with the cutting attachment.
19 Drive Tube
Encloses and protects the drive 
shaft between the engine and 
bearing housing.
EPA / CEPA
The Emission Compliance Period 
referred to on the Emissions 
Compliance Label indicates the number 
of operating hours for which the engine 
has been shown to meet Federal 
emission requirements.
Category
CARB
The Emission Compliance Period used 
on the CARB-Air Index Label indicates 
the terms:
Engine
Single cylinder two-stroke engine
FS 40, FS 40 C
Specifications
A = 300 hours
B = 125 hours
C= 50hours
Extended = 300 hours
Intermediate = 125 hours
Moderate = 50 hours
Displacement: 1.66 cu. in 
(27.2 cc)
Bore: 1.34 in (34 mm)
Stroke: 1.18 in (30 mm)
Engine power to 
ISO 8893:0.9 HP (0.7 kW) 
at 8,500 rpm 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
37 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 attachmentUsers of this unit should carry out only 
the maintenance operations described 
in this manual. STIHL recommends that 
other repair work be performed only by 
authorized STIHL servicing dealers 
using genuine STIHL replacement parts.
Genuine STIHL parts can be identified 
by the STIHL part number, the 
{ logo and, in some cases, by 
the STIHL parts symbol K. The 
symbol may appear alone on small 
parts.
For repairs of any component of this 
unit’s air emissions control system, 
please refer to the air emissions 
systems warranty in this manual. Idle speed: 2,800 rpm
Cut-off speed (rated): 10,000 rpm
Max. output shaft 
speed (cutting 
attachment): 10,600 rpm
Displacement: 1.66 cu. in 
(27.2 cc)
Bore: 1.34 in (34 mm)
Stroke: 1.18 in (30 mm)
Engine power to 
ISO 88931.1 HP (0.8 kW) 
at 8,500 rpm
Idle speed: 2,800 rpm
Cut-off speed (rated): 10,000 rpm
Max. output shaft 
speed (cutting 
attachment): 10,600 rpm
Spark plug (resistor 
type): NGK CMR 6 H
Electrode gap: 0.02 in (0.5 mm)
Fuel tank capacity: 11.5 fl.oz (0.34 l)Standard version
FS 40: 9.7 lbs 
(4.4 kg)
FS 50: 9.7 lbs 
(4.4 kg)
FS 50: with long 
shaft9.9 lbs 
(4.5 kg)
Versions with Easy2Start
FS 40 C: 9.9 lbs 
(4.5 kg)
FS 50 C: 9.9 lbs 
(4.5 kg)
FS 50 C: with long 
shaft10.1 lbs 
(4.6 kg)
FS 40, 
FS 40 C: 57 in (1450 mm)
FS 50, 
FS 50 C: 57 in (1450 mm)
FS 50, 
FS 50 C:with long 
shaft 65 in (1650 mm)
Maintenance and Repairs 
						

							FS 40, FS 40 C, FS 50, FS 50 C
English
38 Observe all country-specific waste 
disposal rules and regulations.
STIHL products must not be thrown in 
the garbage can. Take the product, 
accessories and packaging to an 
approved disposal site for environment-
friendly recycling.
Contact your STIHL servicing dealer for 
the latest information on waste disposal.STIHL Incorporated Limited Warranty 
Policy
This product is sold subject to the STIHL 
Incorporated Limited Warranty Policy, 
available at 
http://www.stihlusa.com/warranty.html.
It can also be obtained from your 
authorized STIHL dealer or by calling 
1-800-GO-STIHL (1-800-467-8445).Not for California
Your Warranty Rights and Obligations
The U.S. Environmental Protection 
Agency (EPA) and STIHL Incorporated 
are pleased to explain the Emission 
Control System Warranty on your 
equipment type engine. In the U.S. new 
1997 and later model year small off-road 
equipment engines must be designed, 
built and equipped, at the time of sale, to 
meet the U.S. EPA regulations for small 
non road engines. The equipment 
engine must be free from defects in 
materials and workmanship which 
cause it to fail to conform with U.S. EPA 
standards for the first two years of 
engine use from the date of sale to the 
ultimate purchaser.
STIHL Incorporated must warrant the 
emission control system on your small 
off-road engine for the period of time 
listed below provided there has been no 
abuse, neglect or improper maintenance 
of your small off-road equipment engine.
Your emission control system includes 
parts such as the carburetor and the 
ignition system. Also included may be 
hoses, and connectors and other 
emission-related assemblies.
Where a warrantable condition exists, 
STIHL Incorporated will repair your 
small off-road equipment engine at no 
cost to you, including diagnosis (if the 
diagnostic work is performed at an 
authorized dealer), parts, and labor.
Disposal
000BA073 KN
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