Instruction Manual

MS 271, MS 271 C, MS 291, MS 291 C
English
54
Maintenance Requirements
The maintenance instructions in this
manual are based on the application of
the recommended 2-stroke fuel-oil
mixture (see also instruction "Fuel").
Deviations from this recommendation
regarding quality and mixing ratio of fuel
and oil may require shorter maintenance
intervals.
Limitations
This Emission Control Systems
Warranty shall not cover any of the
following:
1. repair or replacement required
because of misuse, neglect or lack
of required maintenance
2. repairs improperly performed or
replacements not conforming to
STIHL Limited specifications that
adversely affect performance
and/or durability, and alterations or
modifications not recommended or
approved in writing by STIHL
Limited
3. replacement of parts and other
services and adjustments
necessary for required maintenance
at and after the first scheduled
replacement point
CSA-Standard Z62.3-11 sets certain
performance and design criteria related
to chain saw kickback. To comply with
CSA Z62.3-11:
a. saws of class A and C shall not
exceed 45° computed kickback
angle (CKA). Operation of the chain
brake may be taken into
consideration for compliance with
this requirement (CKA
wb
). If the
chain has stopped before the bar
has reached the maximum
deflection, the requirement also is
complied with if this lower computed
kickback chain stopping angle
(CKA
cs
) does not exceed the limit of
45°
b. saws of class B shall not exceed 25°
CKA under the conditions as
mentioned above and have a guide
bar with a nose radius no greater
than 25 mm. An automatic chain
brake activated upon kickback is
mandatory, so is a low kickback saw
chain
The computed kickback angles are
measured by applying a computer
program to test results from a kickback
test machine.
WARNING
In order to comply with the computed
kickback angle requirements of
CSA Z62.3-11, use only the following
cutting attachments:
N a bar and chain combination as
listed in this instruction manual
N other replacement saw chains for
use on specific powerheads or
N a low-kickback saw chain
STIHL offers a variety of bars and
chains. STIHL reduced-kickback bars
and low-kickback chains are designed to
reduce the risk of kickback injury. Other
chains are designed to obtain higher
productivity or sharpening ease but may
result in a higher kickback tendency.
Please ask your STIHL dealer to
properly match your powerhead with the
appropriate bar/chain combinations to
reduce the risk of kickback injury. Low-
kickback saw chains are recommended
for all powerheads. See the charts of the
STIHL Bar and Chain Information for
details.
WARNING
Use of other, non listed bar/chain
combinations may increase kickback
forces and increase the risk of kickback
injury. New bar/chain combinations may
be developed after publication of this
literature, which will, in combination with
certain powerheads, comply with
CSA Z62.3-11. Check with your STIHL
dealer for such new combination
updates.
CSA Standard