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Technical Information · issue 5 of 1997

New version with catalytic converter 046C; Crankca

Model 046 Chainsaws

IssueTI 5/1997

Full text

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TI 5/1997 page 1
Technical Information

                                                                                              05.97

Model 046 Chainsaws

Contents

1.   046 C: New version with catalytic converter

2.   Crankcase/muffler mounting
3.   Servicing aid (Loctite 272)
4.   Tank housing, tank vent (modified valve)

1. 046 C: New version with catalytic converter

The catalytic converter reduces the amount of        • Metal carrier catalyst, rapid response time
unburnt hydrocarbons in the exhaust gas by about         (20 - 30 seconds), low gas flow resistance
70%. This means the unpleasant smell is reduced,     •   Platinum coating, temperature resistant
as is irritation of the eyes and mucous                  to 1300°C (2375°F)
membranes. It is a further contribution to
protection of the operator and the environment.      A detailed description of the catalytic converter and
                                                     its operation was published in TI 11.93
The catalytic converter installed in the 046 C is    (model 026 C).
exactly the same the one already used in the
044 C:

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Technical Information 05.97 - Page 2

With the exception of 026-specific data (speeds, engine power, etc.), this description also applies to
the 046 C.

1.1 Specifications

Except for its 300 g (10.6 oz) higher weight, the specifications are exactly the same as for other series
046 machines.

Engine power (no change)          4.1 kW (5.6 bhp)
Weight of powerhead
w/out bar and chain               6.8 kg (15 lbs)

1.2 Carburetor adjustment

Corrections to the setting of the high speed screw (H) may be carried out only if an accurate tachometer is
used to check that the maximum permissible engine speed of 13,500 rpm is not exceeded (with properly

tensioned chain). Furthermore, the minimum full-throttle engine speed must not be less than 13,000 rpm.

1.3 Fuel

STIHL 046 C chainsaws with a catalytic converter may only be operated with a mixture of unleaded
brand-name gasoline and STIHL 50:1 high-performance two-stroke engine oil or STIHL HT plus 50:1
synthetic engine oil.
See also TI 11.93, chapter 1.5.

1.4 Crankcase/muffler mounting

Mufflers with a catalytic converter reach higher
operating temperatures than non-catalyst mufflers.

The tapped holes in the 046 C crankcase have
                                                                   a) M6x18
been made deeper and counterbored in order to
optimize the screwed joint for this purpose.

                                                                                  1                      2
Longer screws (M6 x 30) are used to mount the

muffler to the crankcase.
The tightening torque remains unchanged at                        b) M6x30
15 Nm (11.0 lbf.ft).

                                                                                                              145TI015 KN

                                                           a = Original version
                                                           b = New version

                                                           1 = Muffler
                                                           2 = Crankcase

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Technical Information 05.97 - Page 3

2. Crankcase

In the interests of standardizing parts, the original
crankcase 1128 020 2114 (without counterbored
holes, see 1.4) will be replaced by crankcase
1128 020 2116 (with counterbored holes).
The new crankcase is supplied with two M6 x 30
screws to ensure full interchangeability.

2.1 Service note for 046 without catalytic

converter

If the new crankcase 1128 020 2116 (with
counterbored holes) is installed in the course of

a repair, it is essential to use the M6 x 30 screws
supplied to mount the muffler.

• Secure the screws with Loctite 272
Loctite 272 remains secure at temperatures up to
200°C (390°F). Do not use any other threadlocking
adhesive for this particular application.
An instruction sheet will be included in the scope
of supply up to the end of 1998. It points out the

need to use the longer screws.

2.2 Summary

Item      Part Name                                      Original          Neue               Rem.
                                                         version           version

  1       Crankcase;                                    1128 020 2114    1128 020 2116   1)

          including item 3
  2       Screw IS-M6 x 18                              9022 341 1310    ---             2)
  3       Screw IS-M6 x 30 (2x)                         ---              9022 341 1370

Modification to be introduced: in progress
Remarks

1) Original version of part no longer available from factory
2) Original version of part remains available for older machines

3. Servicing aid

Required for model 046 C
Loctite 272 (50 ml bottle)            0786 111 1110

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4. Tank housing, tank vent

In future, air will enter the tank through valve
1110 353 1600.
Tank housing 1128 350 0806 was modified to
accommodate this valve and its part number
changed to 1128 350 0809.

                                                                                                             145TI016 KN
                                                            Left:    Original tank housing
                                                            Right: New version with valve 1110 353 1600

Air enters the tank via the new valve

1110 353 1600 (arrows) as the volume of fuel in
the tank reduces.
However, air cannot flow from the inside outwards:
Pressure can therefore build up in the tank while
the engine is stopped if the fuel is heated by
sunlight or other influences.

Important

                                                                                                            145TI017 KN
Always open the fuel filler cap slowly so that any
excess pressure that has built up is released
gradually and fuel does not spurt out unexpectedly.

Summary

Item      Part Name                                   Original                Neue                  Rem.

                                                      version                 version

  1       Tank housing;                               1128 350 0806           1128 350 0809         1)
          including item 2:

  2       Valve                                       1128 353 1600           1110 353 1600         2) 3)

Modification to be introduced: in progress

Remarks
1) Original version of part no longer available from factory.
2) Original version of part remains available as spare for older machines.
3) New version of part is already in inventory.

Last Technical Information on model 046: 43.96

 1997 Andreas Stihl                                        Andreas Stihl - D1/MTK-st
                                                            Technical Documentation                       5947

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