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Technical Information · issue 32 of 2009

Carburetor; New Fanwheel; Blower Housing

IssueTI 32/2009

Part changes (1)

WasBecomesWhat the bulletin says
4241 704 3400 4241 704 3405 New Fanwheel BG 56, BG 86, SH 56, SH 86 The previous fanwheel 4241 704 3400 will be replaced by the new fanwheel 4241 704 3405.

Full text

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TI 32/2009 page 1
STIH)

Technical Information                                                                       32.2009

  STIHL BG 56, BG 66, BG 86 Blowers                                     – Series 4241
  STIHL SH 56, SH 86 Shredder Vacuums                                   – Series 4241

  Contents
  1. Carburetor
  2. New Fanwheel
  3. Blower Housing

  1.     Carburetor
  Changes to optimize carburetor function have been               The geometry of the tips of the high speed screw (H)
  implemented into the manufacturing process.                     and low speed screw (L) have also been changed.
  The new, modified carburetors can be identified by              The changes have no influence on the function or
  the index letter of the designation engraved on the             adjustment of the previous and new carburetors.
  carburetor body.

                     X XXX D

                                              D
                                                    298TI005 KN

  TI_32_2009_30_01_01.fm                                                                            englisch / English
)m~ge 2                                                                   Technical Information 32.2009

1.1      Overview of changes                          BG 86, SH 86 – Carburetor 4241 120 0600
                                                      The installation of high speed screw (H)
BG 56, SH 56 – Carburetor 4241 120 0601               4241 122 6702 and low speed screw (L)
                                                      4140 122 6800 with modified geometry coincides
The installation of high speed screw (H)              with the change in carburetor designation to C1M-
4241 122 6703 and low speed screw (L)                 S141D.
4241 122 6803 with modified geometry coincides
with the change in carburetor designation to          The new adjusting screws can also be used in older
C1M-S142D.                                            carburetors.

The new adjusting screws can also be used in older    The previous low speed screw (L) 4241 122 6800 is
carburetors.                                          no longer available as a replacement part.

BG 66 – Carburetor 4241 120 0602
Carburetors with the designation C1M-S144B are
technically the same as carburetors C1M-S141D for
BG 86, SH 86 and C1M-S142D for BG 56, SH 56.
The high speed screw (H) 4241 122 6702 and low
speed screw (L) 4241 122 6801 have been installed
since introduction and remain available as
replacements for this carburetor.

1.1.1    Overview
Part No.                   Installed in              Designation of previous   Designation
                                                     carburetor                of new carburetor
4241 120 0601              BG 56, SH 56              C1M-S142A                 C1M-S142D
                                                     C1M-S142C
4241 120 0602              BG 66                     C1M-S144                  C1M-S144B
                                                     C1M-S144A
4241 120 0600              BG 86, SH 86              C1M-S141A                 C1M-S141D
                                                     C1M-S141C

                                                                                   TI_32_2009_30_01_01.fm

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TI 32/2009 page 2
Technical Information 32.2009                                                                    Page 3

1.2     Starting after a long period of storage        3.     Blower Housing
Problems with starting may be experienced if the       Standardizing parts (SH 56)
machine is stored for several months at
temperatures below 41 °F (5 °C).                       The previous blower housing 4241 701 0700 is no
                                                       longer available for the SH 56.
In such a case, press the manual fuel pump several
times to prime the carburetor. Then wait several       The blower housing 4241 700 4102 installed in the
minutes before attempting to start the engine.         SH 86 is now used as a replacement part for the
                                                       SH 56.
Recommendation: Before storing the machine for
a prolonged period, always run the engine until the    Blower housing 4241 700 4102 can also be used for
carburetor is dry. This helps prevent the carburetor   older SH 56 machines.
diaphragms from sticking together – see also
chapter on "Storing the Machine" in the instruction
manual.

2.     New Fanwheel
BG 56, BG 86, SH 56, SH 86
The previous fanwheel 4241 704 3400 will be
replaced by the new fanwheel 4241 704 3405. The
difference between the new fanwheel and previous
fanwheel is the material used.
The new fanwheel can also be used for older
machines.
The previous fanwheel is no longer available as a
replacement part.

TI_32_2009_30_01_01.fm
)m~ge 4                                                                     Technical Information 32.2009

Summary

Item     Part Name                                             Previous        New             Rem.
 1       C1M-S142A, C1M-S142C carburetors;                     4241 120 0601   ---             1)
         including items 3 and 4:
 2       C1M-S142D carburetor;                                 ---             4241 120 0601   2)
         including items 3 and 4:
 3       High speed screw (H)                                  4241 122 6700   4241 122 6703   2)
 4       Low speed screw (L)                                   4241 122 6801   4241 122 6803   2)

 5       C1M-S144A carburetor;                                 4241 120 0602   ---             1)
 6       C1M-S144B carburetor;                                 ---             4241 120 0602   2)

 7       C1M-S141A, C1M-S141C carburetors;                     4241 120 0600   ---             1)
         including items 9 and 10:
 8       C1M-S141D carburetor;                                 ---             4241 120 0600   2)
         including items 9 and 10:
 9       High speed screw (H)                                  4241 122 6700   4241 122 6702   2)
10       Low speed screw (L)                                   4241 122 6800   4140 122 6800   1), 2)

11       Fanwheel                                              4241 704 3400   4241 704 3405   1), 2)
12       Blower housing (SH 56)                                4241 701 0700   4241 700 4102   2)

Remarks
1) Previous version of part no longer available from factory
2) New version of part can also be used for older machines

© ANDREAS STIHL AG & Co. KG, 2009                         Technical Documentation
                                                          D1/MTK-ni

                                                                                      TI_32_2009_30_01_01.fm

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TI 32/2009 page 3

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TI 32/2009 page 4

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