Stihl 181 C Manual

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
29 NGuide the drive link into the bar 
groove (see arrow) and turn the 
tensioning gear to the left as far as 
possible
NFit chain sprocket cover, sliding the 
guide lugs into the engine housing 
openings
When fitting the chain sprocket cover, 
the teeth of the adjusting wheel and the 
tensioning gear must mesh; if 
necessary,Nturn the adjusting wheel (4) a little 
until the chain sprocket cover can 
be slid completely against the 
engine housing
NSwing grip (5) into position (until it 
engages)
NFit wing nut and tighten lightly
NNext step: see "Tensioning the Saw 
Chain"
Retensioning during cutting work:
NSwitch off the engine.
NLoosen the nut.
NHold the bar nose up.
NUse a screwdriver to turn the 
tensioning screw (1) clockwise until 
the chain fits snugly against the 
underside of the bar.
NWhile still holding the bar nose up, 
tighten down the nut firmly.
NGo to "Checking Chain Tension".
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
NCheck chain tension frequently – 
see chapter on "Operating 
Instructions".
135BA011 KN
4
5
2310BA018 KN
7HQVLRQLQJWKH6DZ&KDLQ
VLGHFKDLQWHQVLRQHU
1
142BA063 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
30 Retensioning during cutting work:
NShut off the engine.
NPull out the hinged clip and loosen 
the wingnut.
NTurn the adjusting wheel (1) 
clockwise as far as stop.
NTighten down the wingnut (2) firmly 
by hand.
NFold down the hinged clip.
NGo to "Checking Chain Tension"
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
NCheck chain tension frequently – 
see chapter on "Operating 
Instructions".NShut off the engine.
NWear work gloves to protect your 
hands.
NThe chain must fit snugly against 
the underside of the bar and it must 
still be possible to pull the chain 
along the bar by hand when the 
chain brake is released.
NIf necessary, retension the chain.
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
NCheck chain tension frequently – 
see chapter on "Operating 
Instructions".This engine is certified to operate on 
unleaded gasoline and the STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of high-
quality gasoline and two-stroke air 
cooled engine oil.
Use mid-grade unleaded gasoline with a 
minimum octane rating of 89 ((R+M)/2) 
and no more than 10% ethanol content.
NOTICE
Fuel with an octane rating below 89 may 
increase engine temperatures. This, in 
turn, increases the risk of piston seizure 
and damage to the engine.
The chemical composition of the fuel is 
also important. Some fuel additives not 
only detrimentally affect elastomers 
(carburetor diaphragms, oil seals, fuel 
lines, etc.), but magnesium castings and 
catalytic converters as well. This could 
cause running problems or damage the 
engine. For this reason STIHL 
recommends that you use only quality 
unleaded gasoline!
NOTICE
Gasoline with an ethanol content of 
more than 10% can cause running 
problems and major damage in engines 
and should not be used.
For further details, see 
www.STIHLusa.com/ethanol
The ethanol content in gasoline affects 
engine speed – it may be necessary to 
readjust the carburetor if you use fuels 
with various ethanol contents.
Tensioning the Saw Chain 
(quick chain tensioner)
1
2
001BA112 KN
&KHFNLQJ&KDLQ7HQVLRQ
142BA064 KN
)XHO 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
31
WARNING
To reduce the risk of personal injury 
from loss of control and/or contact with 
the running cutting tool, do not use your 
unit with an incorrect idle adjustment. At 
correct idle speed, the cutting tool 
should not move.
If your machine’s idle speed is 
incorrectly adjusted, have your 
authorized STIHL servicing dealer 
check your machine and make the 
proper adjustments and repairs.
The idle speed and maximum speed of 
the engine change if you switch from a 
fuel with a certain ethanol content to a 
fuel with a much higher or lower ethanol 
content.
This problem can be avoided by always 
using fuel with the same ethanol 
content.
To ensure the maximum performance of 
your STIHL engine, use a high quality 2-
cycle engine oil. To help your engine run 
cleaner and reduce harmful carbon 
deposits, STIHL recommends using 
STIHL HP Ultra 2-cycle engine oil or ask 
your dealer for an equivalent fully 
synthetic 2-cycle engine oil. 
To meet the requirements of EPA and 
CARB we recommend to use STIHL HP 
Ultra oil.
STIHL MotoMix
STIHL recommends the use of STIHL 
MotoMix. STIHL MotoMix has a high 
octane rating and ensures that you 
always use the right gasoline/oil mix 
ratio.STIHL MotoMix uses STIHL HP Ultra 
two-stroke engine oil suited for high 
performance engines.
For further details, see 
www.STIHLusa.com/ethanol
If not using MotoMix, use only STIHL 
two-stroke engine oil or equivalent high-
quality two-stroke engine oils that are 
designed for use in air cooled two-cycle 
engines.
The use of non-seasonal gasoline 
blends may increase the potential for 
pressure to build in the fuel tank during 
operation. For example, using a winder 
blend during the summer will increase 
pressure in the fuel tank. Always use 
gasoline blends appropriate to the 
season, altitude and other 
environmental factors.
Do not use BIA or TCW rated (two-
stroke water cooled) mix oils or other 
mix oils that state they are for use in both 
water cooled and air cooled engines 
(e.g., outboard motors, snowmobiles, 
chain saws, mopeds, etc.).
WARNING
Take care when handling gasoline. 
Avoid direct contact with the skin and 
avoid inhaling fuel vapor. When filling at 
the pump, first remove the container 
from your vehicle and place the 
container on the ground before filling. To 
reduce the risk of sparks from static 
discharge and resulting fire and/or 
explosion, do not fill fuel containers that 
are sitting in or on a vehicle or trailer.
The container should be kept tightly 
closed in order to limit the amount of 
moisture that gets into the mixture.The machine‘s fuel tank should be 
cleaned as necessary.
Fuel mix ages
If not using MotoMix, only mix sufficient 
fuel for a few days of work, not to exceed 
30 days of storage. Store in approved 
fuel-containers only. When mixing, pour 
oil into the container first, and then add 
gasoline. Close the container and shake 
it vigorously by hand to ensure proper 
mix of oil and gasoline.
Dispose of empty mixing-oil containers 
only at authorized disposal locations. Gaso-
lineOil (STIHL 50:1 or equiva-
lent high-quality oils)
US gal. US fl.oz.
12.6
2 1/2 6.4
5 12.8 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
32
Preparations
NBefore fueling, clean the filler cap 
and the area around it to ensure that 
no dirt falls into the tank.
Always thoroughly shake the mixture in 
the canister before fueling your 
machine.
NPosition the machine so that the 
filler cap is facing up.
WARNING
In order to reduce the risk of fire and 
other personal injury from escaping gas 
vapor and fumes, remove the fuel filler 
cap carefully so as to allow any pressure 
build-up in the tank to release slowly
Filler cap markings
Filler caps and fuel tanks may be 
marked in different ways.Depending on the version, your unit may 
be equipped with a filler cap and fuel 
tank with or without symbols.
Filler cap without symbols
Opening
NRaise handle.
NTwist filler cap counterclockwise 
(approx. 1/4 turn).NRemove the filler cap.
Refueling
Take care not to spill fuel while fueling 
and do not overfill the tank – leave 
approx. 1/2" (13 mm) air space.
Closing
Handle is in an upright position:
NInsert the cap – positioning marks 
on the cap and the fuel tank opening 
must line up.
NThe cap should drop fully into the 
opening in this position.
Fueling
001BA229 KN
/HIW )LOOHUFDSZLWKRXWV\PEROV
5LJKW )LOOHUFDSZLWKPDUNLQJVDQG
V\PEROVRQFDSDQGWDQN
001BA240 KN
001BA218 KN
001BA219 KN
001BA224 KN
001BA220 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
33 NPush the filler cap down and twist it 
clockwise until it engages.
NFlip the handle down.
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 out 
of position vis-à-vis the top.
NSuch misalignment can result from 
handling, cleaning or an improper 
attempt at tightening.NTo correct a misalignment, turn the 
cap (with the grip up) until it drops 
fully into the tank opening.
NTwist the cap counterclockwise as 
far as it will go (approx. 1/4 turn) – 
this will twist the base of the cap into 
the correct position.
NTwist the cap clockwise, closing it 
normally – see the sections 
"Closing" and "Checking for proper 
closure."
NIf your cap still does not tighten 
properly, it may be damaged or 
broken; immediately stop use of the 
unit and take it to your authorized 
STIHL dealer for repair.
Filler cap with markings and symbols
Opening
NRaise handle.
001BA221 KN
001BA222 KN
001BA223 KN
/HIW %DVHRILPSURSHUO\DOLJQHG
FDSZLWKRSHQVSDFH
5LJKW %DVHRIFDSFRUUHFWO\SRVL-
tioned for installation
001BA225 KN
001BA227 KN
001BA226 KN
001BA236 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
34 NTwist filler cap counterclockwise 
(approx. 1/4 turn).
Markings on filler cap and housing must 
align.
NRemove the filler cap.
Refueling
Take care not to spill fuel while fueling 
and do not overfill the tank – leave 
approx. 1/2" (13 mm) air space.Closing
Handle is in an upright position:
NPosition filler cap – markings on filler 
cap and housing must align.
NPush the filler cap down as far as it 
will go.
NPush the filler cap down and twist it 
clockwise until it engages.
Then the markings on filler cap and 
housing will align.NFlip the handle down.
Filler cap is now closed.
If the filler cap will not engage into the 
tank housing
The base of the filler cap is rotated in 
relation to the upper part.
NLook at the black alignment marks 
on the top of the filler cap.
001BA232 KN
001BA234 KN
001BA237 KN
001BA234 KN
001BA233 KN
001BA231 KN
001BA235 KN
001BA241 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
35 NWith the filler cap in the filling neck, 
twist it counterclockwise until it 
drops into its seat.
NContinue to twist the filler cap 
counterclockwise (approx. 1/4 turn) 
– this will twist the base of the cap 
into the correct position.
NWhile pushing down on the cap, 
twist the filler cap clockwise and 
close it – see section "Closing."For automatic and reliable lubrication of 
the chain and guide bar – use only an 
environmentally compatible quality 
chain and bar lubricant. Rapidly 
biodegradable STIHL BioPlus is 
recommended.
NOTICE
Biological chain oil must be resistant to 
aging (e.g. STIHL BioPlus),  since it will 
otherwise quickly turn to resin. This 
results in hard deposits that are difficult 
to remove, especially in the area of the 
chain drive and chain. It may even cause 
the oil pump to seize.
The service life of the chain and guide 
bar depends on the quality of the 
lubricant. It is therefore essential to use 
only a specially formulated chain 
lubricant.
WARNING
Do not use waste oil. Renewed contact 
with waste oil can cause skin cancer. 
Moreover, waste oil is environmentally 
harmful.
NOTICE
Waste oil does not have the necessary 
lubricating properties and is unsuitable 
for chain lubrication.
Preparations
NThoroughly clean the oil filler cap 
and the area around it to ensure that 
no dirt falls into the tank.
NPosition the machine so that the 
filler cap is facing up.
NOpen the filler cap.
Filling chain oil tank
NRefill the chain oil tank every time 
you refuel.
Take care not to spill chain oil while 
refilling and do not overfill the tank.
NClose the filler cap.
There must still be a small amount of oil 
in the oil tank when the fuel tank is 
empty.
If the oil level in the tank does not go 
down, the reason may be a fault in the oil 
supply system: Check chain lubrication, 
clean the oilways, contact your dealer  Left: Base of filler cap is rotated – 
interior marking (1) is aligned 
with the exterior marking.
Right: Base of filler cap is in the cor-
rect position – interior 
marking is below the clip. It 
does not align with the exte-
rior marking.
1
001BA238 KN
001BA239 KN
&KDLQ/XEULFDQW)LOOLQJ&KDLQ2LO7DQN
001BA158 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
36 for assistance if necessary STIHL 
recommends that you have servicing 
and repair work carried out exclusively 
by an authorized STIHL servicing 
dealer.
The saw chain must always throw off a 
small amount of oil.
NOTICE
Never operate your saw without chain 
lubrication. If the chain runs dry, the 
whole cutting attachment will be 
irretrievably damaged within a very short 
time. Always check chain lubrication and 
the oil level in the tank before starting 
work.
Every new chain has to be broken in for 
about 2 to 3 minutes.
After breaking in the chain, check chain 
tension and adjust if necessary – see 
"Checking Chain Tension".
Locking chain with chain brake
–in an emergency
–when starting
–at idling speed
The chain is stopped and locked when 
the hand guard is pushed toward the bar 
nose by the left hand – or when brake is 
activated by inertia in certain kickback 
situations.
Checking Chain Lubrication
143BA024 KN
&KDLQ%UDNH
143BA011 KN 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
37
Releasing the chain brake
NPull the hand guard back toward the 
front handle.
NOTICE
Always disengage chain brake before 
accelerating engine and before starting 
cutting work. The only exception to this 
rule is when you check operation of the 
chain brake.
High revs with the chain brake engaged 
(chain locked) will quickly damage the 
powerhead and chain drive (clutch, 
chain brake).
The chain brake is designed to be 
activated also by the inertia of the front 
hand guard
if the forces are sufficiently high. The 
hand guard is accelerated toward the 
bar nose - even if your left hand is not 
behind the hand guard, e.g. during a felling cut. The chain brake will operate 
only if it has been properly maintained 
and the hand guard has not been 
modified in any way.
Check operation of chain brake
Before starting work: Run engine at idle 
speed, engage the chain brake (push 
hand guard toward bar nose). 
Accelerate up to full throttle for no more 
than 3 seconds – the chain must not 
rotate. The hand guard must be free 
from dirt and move freely.
Chain brake maintenance
The chain brake is subject to normal 
wear. It is necessary to have it serviced 
and maintained regularly by trained 
personnel, such as your STIHL servicing 
dealer, at the following intervals:
Winter shutter (MS 211 only)
At temperatures below +50°F (+10°C):
NRemove the shroud – see "Shroud".
NUse the combination wrench to turn 
the shutter, next to the spark plug, 
45° counterclockwise.
NInstall the shroud – see "Shroud".
Heated air is now drawn in from around 
the cylinder to warm the carburetor – this 
helps prevent carburetor icing.
143BA012 KN
)XOOWLPHXVDJH HYHU\
PRQWKV
3DUWWLPHXVDJH HYHU\
PRQWKV
2FFDVLRQDOXVDJH HYHU\
PRQWKV
:LQWHU2SHUDWLRQ
:LQWHURSHUDWLRQ
6XPPHURSHUDWLRQ
1
533BA003 KN
2 
						

							MS 171, MS 181, MS 181 C, MS 211, MS 211 C
English
38
NOTICE
At temperatures above +68°F (+20°C), 
return the shutter to the summer 
position. This is necessary to avoid 
engine running problems and 
overheating.
Fitting the cover plate
(Special accessory, not for Easy2Start 
models)
NPlace the cover plate (1) in position 
and secure it with the screws (2).
NIf your saw is very cold, start the 
engine and run it until it reaches 
normal operating temperature.
MS 211 only: When the cover plate is 
fitted, the winter shutter may be in either 
the winter or summer positions. Move it 
to the winter position when temperatures 
drop below +50°F (+10°C).
Versions with Easy2Start
WARNING
This machine is extremely simple and 
easy to start, even for children.
To reduce the risk of serious or fatal 
injury:
–do not allow children or other 
unauthorized persons to attempt to 
start or otherwise use the machine
–never allow children or 
unauthorized persons access to the 
machine
–never leave the machine 
unattended while working or during 
work breaks
–after work, store in a safe, secure 
location out of the reach of children 
and other unauthorized persons
Positions of Master Control lever
Stop 0 – engine off – the ignition is 
switched off.
Normal run positionF – engine runs or 
can fire.
Starting throttle?n – this position is 
used to start a warm engine. The Master 
Control lever moves to the normal run 
position as soon as the throttle trigger is 
squeezed.
Choke shutter closedl – this position 
is used to start a cold engine.
Setting the Master Control lever
To move the Master Control lever from 
the normal run position (F) to choke 
closed (l), press down the throttle 
lockout and squeeze the throttle trigger 
22
1
533BA014 KN
6WDUWLQJ6WRSSLQJWKH
(QJLQH
STOP
0
001BA140 KN