Shroud; Checking Chain Tension; Fuel - Stihl MS 271 Instruction Manual

English
► Check chain tension frequently – see chapter
on "Operating Instructions".

10 Shroud

10.1 Remove shroud
► Move the Master Control Lever to the stop
position 0
► Push the front hand guard forwards – the saw
chain is blocked
1
► Loosen screws (1)
► Remove the shroud (2)
10.2 Refitting the shroud
► Refit the shroud and tighten the screws

11 Checking Chain Tension

► Shut off the engine.
► Wear work gloves to protect your hands.
► The chain must fit snugly against the under‐
side of the bar and it must still be possible to
pull the chain along the bar by hand.
► If necessary, retension the chain.
A new chain has to be retensioned more often
than one that has been in use for some time.
► Check chain tension frequently – see chapter
on "Operating Instructions".

12 Fuel

This engine is certified to operate on unleaded
gasoline and with the mix ratio 50:1.
20
1
2
1
Your engine requires a mixture of high-quality
premium gasoline and high-quality two-stroke
air-cooled engine oil.
Use premium branded unleaded gasoline with a
minimum octane rating of 89 (R+M)/2.
Note: Models equipped with a catalytic converter
require unleaded gasoline. A few tankfuls of lea‐
ded gasoline can reduce the efficiency of the cat‐
alytic converter by more than 50%.
Fuel with a lower octane rating may result in pre‐
ignition (causing "pinging") which is accompa‐
nied by an increase in engine temperature. This,
in turn, increases the risk of the piston seizure
and damage to the engine.
The chemical composition of the fuel is also
important. Some fuel additives not only detrimen‐
tally affect elastomers (carburetor diaphragms,
oil seals, fuel lines etc.), but magnesium castings
as well. This could cause running problems or
even damage the engine. For this reason it is
essential that you use only high-quality fuels!
Fuels with different percentages of ethanol are
being offered. Ethanol can affect the running
behaviour of the engine and increase the risk of
lean seizure.
Gasoline with an ethanol content of more than
10% can cause running problems and major
damage in engines with a manually adjustable
carburetor and should not be used in such
engines.
Engines equipped with M-Tronic can be run on
gasoline with an ethanol content of up to 25%
(E25).
Use only STIHL two-stroke engine oil or equiva‐
lent high-quality two-stroke air-cooled engine oils
for mixing.
We recommend STIHL 50:1 two-stroke engine
oil since it is specially formulated for use in
STIHL engines.
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.
Do not use BIA or TCW (two-stroke water
cooled) mix oils!
10 Shroud
0458-574-8221-D