Technical Information · issue 35 of 1996
New chainsaw
IssueTI 35/1996
Engine family 1124
Full text
Page 1 of 8
Technical Information
35.96
New STIHL 088 Chainsaws - Series 1124
The STIHL 088 is a new heavy-duty production The new lightweight flywheel with polymer fan and
saw for big timber and hardwood. It has been small, low weight high-power magnets increases
developed on the basis of the STIHL 084 and cooling air throughput by 20%. Its lower weight
extends the line of high-performance professional also improves engine acceleration from idle to
saws. maximum speed.
The engine delivers high power and plenty of It also enhances handling and control of the saw,
torque at relatively low revs. reduces the load on the main bearings.
A new longlife air filter system with easily changed The decompression valve releases the compres-
filter elements and optimized sealing helps reduce sion in the combustion chamber during starts and
the time required for maintenance and increase thus reduces the effort required to pull the starter
operational reliability. rope.
)Technical Information 35.96 - Page 2
&RQWHQWV
1. Technical Description
2. Specifications
3. Special Accessories for User
4. Service Accessories
5. Repairs
6. Spare Parts
1.======Technical Description
Comparisons made in this chapter describe the
differences between the STIHL 088 and STIHL
084.
1.1=====Air Filter System
The new air filter system is characterized by
excellent filtering efficiency, long periods between
cleanings and ease of use. Cleaning is necessary
only when there is a noticeable drop in engine
power. No tools are required to remove the filter
element.
Carburetor box cover, filter element and filter base
are clamped together when the carburetor box
cover’s mounting screw is tightened.
The peripheral sealing lips on the filter element
(arrows) help to provide an optimum seal.
The STIHL 088 can be adapted to suit different
operating conditions by installing different filter
elements. Conversions are simple and require
145TI002 SC
no tools:
• Remove the carburetor box cover.
• Change the filter element.
• Refit the carburetor box cover.
The following filter elements are available
(they are color-coded for easier identification):
1.1.1=Winter Filter
Green, with wire mesh for winter operation.
1
1.1.2=HD Filter===============================================================================O
Black, for dry and very dusty operating sites.
The filter element (2) is protected from coarse dirt
by a dry felt prefilter (1).
145TI003 SC
Left: Standard filter
Right: HD filter
)Technical Information 35.96 - Page 3
STIHL filters (Winter and HD) should be used in a
dry condition.
Do not impregnate with oil!
To reduce the risk of icing up, the HD filter should
be replaced by a winter filter in snow operating
conditions.
1.2===Compensator
The compensator keeps the fuel content in the
mixture constant at all times, irrespective of how
dirty the air filter is.
The mixture cannot become over-rich and it is no
longer necessary to change the setting of the high
speed screw as contamination of the air filter
builds up.
For detailed description of compensator see
TI 07.91 (STIHL 066).
1.3===Intake Air Flow======================================fo
The flow of intake air has been optimized by the
new flange (1).
This results in improved air flow and higher torque.
171TI002 KN
1 New flange
1.4===Engine
The crankshaft has been uprated with a wider
big-end bearing.
The crankshaft and crankcase have been
strengthened for this purpose.
1.5===Cooling
Cylinder cooling surface area has been increased.
The volume of cooling air has been upped approx.
20% as a result of the new lightweight flywheel.
)Technical Information 35.96 - Page 4
1.6===Decompression Valve
1.6.1=Construction
3
The main components of the decompression valve 1
are the body (1) and plunger (2).
The plunger (2) moves axially in the valve body.
The bottom end of the plunger is cone-shaped.
2
137TI006 KN
Three spring-loaded balls (3), each offset 120°,
hold the plunger (2) in its upper or lower position.
The complete valve is screwed into the cylinder.
1.6.2=Function
Before starting, the plunger (2) is pushed into its
lower position. The cone moves away from the 3
body (1), the decompression valve is open. 1
The crankshaft is rotated via the rewind starter.
The upward stroke of the piston causes the
2
mixture in the cylinder to be compressed. A small
137TI007 KN
amount of the pressure in the cylinder is pushed
out through the bore in the valve body (see arrow).
The remaining air in the cylinder is compressed
but the resulting pressure is lower than the
decompression valve’s closing pressure.
Only after the combustible mixture is ignited does
the pressure in the cylinder exceed the
decompression valve’s closing pressure.
The plunger (2) is then pushed upwards and the
cone closes the bore.
The shroud now has an opening to accommodate
the decompression valve.
The area around the opening is raised (see
arrow) to protect the decompression valve from
accidental contact.
A cover 1122 084 1405 is fitted between the
cylinder and shroud to help prevent the ingress
of dust and dirt.
171TI003 KN
)Technical Information 35.96 - Page 5
1.7====Exhaust Muffler
A large baffled cast lightmetal muffler is installed in
the STIHL 088 for more efficient silencing.
The muffler (1) is secured to the cylinder (4) with
two wedges (2) and a spring (3).
2 1 2
3
171TI004 KN
Two straps (5) are used to secure the muffler to
the crankcase (6).
5
5
171TI005 KN
6
1.8====Tank Vent
The STIHL 088 is equipped with an optimized fuel
tank vent valve.
The tank vent is designed so that the valve opens
as soon as the saw runs (fuel is drawn from tank).
Vacuum in the fuel tank is equalized via the cap
(3), sintered filter (2) and the valve (1). 3 2
The cap protects the sintered filter from surface
icing and ensures good air circulation (see arrow)
in a low-dust zone of the carburetor box. The
sintered filter helps prevent contamination entering
171TI006 KN
the valve. 1
)Technical Information 35.96 - Page 6
1.9=====Antivibration System
The rubber buffers of the STIHL 046 have been tu-
ned to reduce vibrations.
1.10=Cutting Attachments
The STIHL 088 can be equipped with the same
cutting attachments as the STIHL 084.
2.======Specifications
Comparisons made in this chapter describe the
differences between the STIHL 084 and STIHL 088.
084=====================088
Engine speed at max. power: 9,300 rpm 8,500 rpm
Max. torque: 7.5 Nm (5.5 lb.ft) 8.0 Nm (5.9 lb.ft)
at 6,000 rpm at 6,000 rpm
Weight: 9.4 kg (20.7 lb) 9.9 kg (21.8 lb)
Power-to-weight ratio:
Fuel tank capacity:
1.5 kg/kW
1250 cm3 (2.64 US pt)
1.6 kg/kW
1300 cm3 (2.75 US pt)
Oil tank capacity: 630 cm3 (1.33 US pt) 700 cm3 (1.48 US pt)
Max. permissible engine speed
with Rollomatic bar and chain: 12,500 rpm 12,000 rpm
Mean idle speed: 2,000 rpm 2,500 rpm
Air filter; HD filter w/oil Filter element wire mesh (winter option)
(cotton fabric) Filter element - Dry
Sound pressure levelLpeq
to ISO 71821) 102 dB(A) 101 dB(A)
Sound power level Lweq
to ISO 92071) 111 db(A) 112 dB(A)
3.======Special Accessories for User
0.404", 8-tooth rim sprocket kit 1124 007 1027
0.404", 7-tooth rim sprocket kit 1124 007 1024
3/8", 8-tooth rim sprocket kit 1124 007 1025
3/8", 8-tooth spur sprocket 1124 640 2004
0.404", 7-tooth spur sprocket 1124 640 2005
Chain scabbard extension 0000 792 9133
)Technical Information 35.96 - Page 7
4.====Service Accessories
4.1===Special Servicing Tools
New part required for model 088
Part Name=========================Part No.================Application
Flange 1124 850 4205 Sealing muffler opening for
leakage test
Other special servicing tools required are listed in the STIHL 088 service manual.
4.2===Servicing Aids
New servicing aids
Part Name=========================Part No.
Gasket set 088 1124 007 1051
Carburetor parts kit 1124 007 1060
Gasket panel 088 0457 281 2204 fo
Other servicing aids required are listed in the STIHL 088 service manual.
5.====Repairs
If the saw is started up in the course of repairs or
maintenance work, always observe all local
regulations and the safety precautions outlined in
the owner’s manual.
5.1===Service Notes
5.1.1=Use locking strip only when
======decompression valve is closed
Locking strip 0000 893 5903 (for blocking crank-
shaft) must not be inserted in the spark plug hole
until the decompression valve is closed. If the
decompression valve is open, it may be bent by
the force of the piston and locking strip.
5.1.2=Removing the Cylinder
In order to avoid the risk of damage to the piston
(i.e. piston snagging on edge of gasket), use a
knife to separate the gasket from the base of the
cylinder before taking the cylinder off the piston.
137TI002
)Technical Information 35.96 - Page 8
5.2=====Test Data
5.2.1=Leakage Test
Plug 1122 025 2200 must be installed in place of
the decompression valve before carrying out the
leakage test (see service manual).
The decompression valve can be removed and
installed with a standard commercial deep well
13-mm socket.
Tightening torque 14 Nm (10.3 lbf.ft).
(QJLQH
Pressure test 0.6 bar (8.7 psi)
Vacuum test 0.6 bar (8.7 psi)
&DUEXUHWRU
Pressure test 0.4 bar (5.8 psi)
5.3=====Tightening Torques
Refer to STIHL 088 service manual for tightening
torques.
5.4=====Repair Times
All repair times are the same as for the STIHL 084.
6.======Spare Parts
A separate illustrated parts list is available for the
STIHL 088.
Andreas Stihl D1/MTK-na
© 1996 Andreas Stihl Technical Documentation 5872 Page 2 of 8
Page 3 of 8
Page 4 of 8
Page 5 of 8
Page 6 of 8
Page 7 of 8
Page 8 of 8
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.