Technical Information · issue 44 of 1994
Uprated engine FS 74, FS 76
IssueTI 44/1994
From serial 29 034 635, 29 049 102
Full text
Page 1 of 3
Technical Information
44.94
Brushcutters STIHL FS 74 and 76 - Series 4133
Power increase
As from the machine numbers specified in the
summary, the brushcutters FS 74 and 76 will be
available with a more powerful engine unit. The
engine power has been increased by approx. 15%
to 0.8 kW (1.1 bhp).
This increase has been achieved by:
● changing the port timing
● increasing the compression
● enlarging the cross-section of the intake port
● changing the shape of the transfer ports
● changing the shape of the gasket and
spacer flange
The new cylinder, gasket and spacer flange
versions are generally used as replacement parts.
Cylinder
The new cylinder differs from the original version
in that the cylinder base flange is approx. 3 mm
thicker and the intake cross-section is larger.
The original cylinder version was secured with
10,5
spline screws of size M5 x 16 while the new
version is secured with spline screws of size
9
M5 x 20.
10
7
In order to ensure that they can be replaced, the
new versions of the cylinder and cylinder with
piston will be issued with size M5 x 20 screws for 15 19
replacement for a period of approx. three years.
356TI001
Original New
version version Page 2 of 3
Technical Information 44.94 - Page 2
Gasket
The window for the gas mixture is 19 mm wide in
the new gasket, as compared with only 16 mm in
the original version.
The new gasket can be installed in machines of
the old version.
356TI002
Original gasket New gasket
Spacer flange
The opening of the new spacer flange is
19 mm wide on the side facing the cylinder. The
service notes must be observed when installing
the new spacer flange in machines of the old
version.
Service notes
Only replacement parts of the new type may
be used when repairing machines of the new
version, otherwise a deterioration in power output
and malfunctions must be expected.
The power output of machines of the original
version can only be increased to approx. 0.8 kW
(1.1 bhp) if all new parts are installed.
The new cylinder must be mounted with the
3
M5 x 20 screws supplied in all cases; tightening 4
torque 10 Nm.
1
The screw connection filter base / carburetor / 2
flange / cylinder must be checked when installing
the new spacer flange in machines of the original
version:
356TI003
Size M 5 x 56 (1) screws and plugs 4133 122 6900
(2) must be used in conjunction with the new spa-
cer flange. The spacer flange must be secured to
the cylinder with size M 5 x 25 screws (3) and A
5.3 washers (4). Page 3 of 3
Technical Information 44.94 - Page 3
Summary
Part name Original New Key Rem. MOQ
version version H
Cylinder with piston; 4133 020 1200 4133 020 1201 1) 1
including items 1 and 2:
Cylinder; 4133 022 0500 4133 020 1250 1 1) 1
including item 2:
Spline screw
IS-M 5 x 16 (2x) 9022 341 0980 --- 2)
Spline screw
--- 9022 371 1020
IS-M 5 x 20 (2x) 2 10
Other parts as before
Gasket 4133 129 0900 4133 129 0902 3) 1
Spacer flange assy.; 4133 120 2202 --- 3)
including items 3 to 6:
Spacer flange -*- 4133 121 1602 3 4) 1
Spline screw
IS-M 5 x 56 (2x) 9007 319 1121 9007 319 1121 4
Hexagon nut M 5 (2x)
Plug (2x)
9210 261 0700
4133 122 6900
9210 261 0700
4133 122 6900
5
6
Modification to be introduced:
- FS 74 from machine No. X 29 049 102
- FS 76 from machine No. X 29 034 635
Remarks
1) Original version of part is no longer available from factory
2) Original version of part remains available
3) Original version of part will be supplied from factory only as long as existing stocks lasts
4) Original version of part is not available as seperate item
Last Technical Information on models FS 74 and 76: 01.94
Waiblingen, January 13 1995 Andreas Stihl
D1/MTK-na Technical Documentation Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.