Stihl 051 AV Electronic Service Manual
What's Included?
Lifetime Access
Fast Download Speeds
Online & Offline Access
Access PDF Contents & Bookmarks
Full Search Facility
Print one or all pages of your manual
STIHL Dli7, D7S
SERVICE MANUAL
050 AV, 051 AV, 051 AV electronic,
075 AV electronic,
076 AV electronic
FOREWORD
This Service Manual covers model
050, 051 and 075 chain saws up to
machine number 5 277 720 as well as
later machines unless technical infor-
mation bulletins have been issued in
the meantime with updated repair
procedures.
With the exception of the rewind starter
and the ignition system, the new 076
and the 075 are identical. The relevant
engineering changes are outlined in
technical information bulletin number
27.80.
In the event of faults it is quite possible
that a single fault may have several
causes. It is therefore advisable to
contsult the " Troubleshooting Chart"
in each chapter when tracing faults.
We also recommend that you make
use of the exploded views in the
illustrated parts lists when carrying out
repair work.
This service manual and all technical
information bulletins are intended ex-
clusively for the use of STIHLservicing
dealers and staff and must not be
passed on to third parties.
Repair work is made considerably
easier if the chain saw is mounted on
assembly stand 591 0 850 3100. The
saw is easily attached to the stand by
means of the two bar mounting studs
and collar nuts.
ST/HJ.:
While on the assembly stand the chain
saw can be swivelled into any required
position within a cartain range to suit
the repair in question. This not only has
the advantage of keeping the compo-
nent in the best position for the repair
but also leaves both hands free for the
work and thus effects a considerable
time saving.
1
SPECIAL TOOL MANUAL
Our special tool manual illustrates
and lists the part numbers of all avai-
lable machine-related tools as well
as general purpose tools for all
machines.
The special tool manual is available
in various languages and can be or-
dered by quoting the appropriate part
number listed hereunder.
German 0455 901 0023
English 0455 901 0123
French 0455 901 0223
Spanish 0455 901 0323
Yugoslav 0455 901 0423
Swedish 0455 901 0523
Italian 0455 901 0723
Portuguese 0455 901 1223
3
8.4 P1ckup Hose/P1ckup Boay 58
8.5 Cover Plate/Worm 58
8.6 Disassembly and Repa1r
of 011 Pump 58
8.7 Manual 011 Pump 60
8. 7.1 Construction and OperatiOn
ot Manual 011 Pump 60
8.7.2 D1sassemb1y ana Repa1r 60
9. Decompression Valve 61
9.1 Construction ana
Operat1on 61
10. Fuel System 62
10.1 ConstructiOn ana Operat1on
of Carburetor 62
1 0.1.1 Operation of Fuel Pump 62
1 0.1 2 Operation ot Carburetor 62
10.2 Troubleshooting Chart 64
10.3 Leakage 1 est (Pressure
Test) on Carburetor 66
1 0.4 Disassembly ot Carburetor 66
1 0.5 Repair of Carburetor 67
10.6 Carburetor AOJUStment 70
1 0 7 Fuel Lme ana lank Vent 70
1 0 8 A1r F1lter 71
4
1. SPECIFICATIONS
051 AV (050 AV), 075 AV,
076AV
1.1 Engine
1.2 Fuel System
STIHL single cylinder two-stroke engine with specially processed cylinder bore
Displacement:
Cylinder bore:
Stroke:
Compression ratio.
Power output:
Max. torque:
Max. permissible engine speed:
Mean idle speed:
Crankshaft:
Crankshaft bearings:
Crankpin:
Big-end bearing:
Piston pin:
Small-end bearing:
Rewind starter:
Starter rope:
Clutch:
051:89 cm
3
075; 076: 111 cm
3
051:52 mm
075; 076: 58 mm
42mm
9.5:1
051: 4.3 kW (5.8 DIN HP) at 7000 rpm
075; 076: 5.15 kW (7.0 DIN HP)
at 7000 rpm
051: 5.9 Nm (0.6 kpm) at 5000 rpm
075; 076: 6.8 Nm (0.7 kpm)
at 5000 rpm
10000 rpm
2000 rpm
two-part drop forging
2 deep-groove ball bearings
18.0 mm dia.
Needle cage
13.0 mm dia.
Needle cage
Friction shoe system with automatic
starter rope rewind mechanism
4.5 mm dia., 1000 mm long
Centrifugal clutch with press-fitted linings, 86 mm dia.
Clutch engages at: approx. 2700 rpm
Crankcase leakage test:
with overpressure:
with vacuum:
Carburetor:
Adjustment:
High speed adjustment screw H:
Low-speed adjustment screw L:
Carburetor leakage test with
overpressure:
Fuel capacity:
0.6 bar (8.7 lbf/in
2
)
0.4 bar (5.8 lbf/in
2
)
All position diaphragm carburetor with
integral fuel pump
Open 1 turn
Open 1
1
/4 turns
(basic setting with
screws initially hard against their seats)
0.4 bar
051: 0.91itre
1.3 Ignition System
Fuel mixture:
Air filter
5
Regular grade gasoline and two-cycle
engine oil. Mix ratio 1:40 with STIHL
two-cycle engine oil; 1:25 with other
branded two-cycle engine oils
Flocked wire mesh element
051 AV (050 AV) up to machine No. 3 001 400
Type : Breaker-controlled magneto ignition
Magneto edge gap : 12 -16 mm
Air gap:
Ignition timing :
Ignition advance angle:
Breaker point gap :
Condenser :
Ignition armature :
051 AVE, 075 AVE; 076 AVE
Type:
Air gap:
Ignition timmg :
Ignition advance angle:
Ignition armature :
Spark plug (suppressed):
051 :
075; 076:
(9- 13mmuptomachineNo.2981245)
0.15- 0.3 mm
1.9-2.1 mm before T.D.C.
(2.3 - 2.7 mm up to machine
No. 2 981 245)
22° -23° before T.D.C.
(24°- 26° before T.D.C. up to machine
No. 2 981 245)
0.35 - 0.4mm
Capacitance 0.6 - 0.9 ,_,F
Coil winding resistance
Primary Secondary
approx. 1!1 approx. 8.7k0
Transistor-controlled (breakerless)
magneto igniton
0.15-0.25 mm
2.5 mm before T.D.C.
25° before T.D.C.
as 050/051
Bosch WSR 6 F (formerly WKA 200
TR 6) , Champion RCJ 6 Y or NGK
BPM- 7, Heat range 175
Bosch WSR 6 F (formerly WKA 200
TR 6) , Champion RCJ 6 Y, Heat
range 225, Electrode gap 0.5 mm,
Spark plug thread M 14 x 1.25;
9.5 mm long
6
1.4 Tightening Torques Crankshaft nut-Ignition side M 8x1:
Sprocket side M 12x1.51eft-hand:
Clutch spider:
Hub:
Decompression valve or plug:
M 6 hex. nuts :
M 5 hex. nuts:
M 5 socket head screws:
M 5 pan head screws:
M 4 pan head screws:
Spark plug :
Collar nuts:
1.5 Cutting Attachment Guide bars :
Bar lengths:
Oilomatic chain :
Chain sprocket:
Chain speed :
Chain lubrication:
Max. oil delivery rate:
Min. oil delivery rate :
Oil tank capacity:
35 Nm (3.5 kpm)
60 Nm (6.0 kpm)
40 Nm (4.0 kpm)
75 Nm (7.5 kpm)
12 Nm (1 .2 kpm)
8 Nm {0.8 kpm)
4 Nm (0.4 kpm)
8 Nm (0.8 kpm)
5 Nm (0.5 kpm)
2.5 Nm (0.25 kpm)
25 Nm (2.5 kpm)
25 Nm (2.5 kpm)
STIHL Duromatic guide bars with
stellite-tipped nose.
STIHL Rollomatic guide bars with
sprocket nose.
Both types with corrosion-resistant
finish and induction hardened rails.
051 : 43, 53, 63 and 75 em
075 : 43, 53, 63, 75 and 90 em
9.32 mm ( 3/ a" ) pitch
10.26 mm (0.404 " ) pitch
12 .7 mm ('12'' ) pitch
a-tooth for 9.32 mm (3 /a") pitch
7-tooth for 10.26 mm (0.404" ) pitch
6-tooth for 12.7 mm (
1
12 '') pitch
16.8 m/s at 8500 rpm with 0.404" chain
Speed-controlled oil pump with pump
plunger; operative only when chain is
running. Additional flow quantity con-
trol by means of adjusting screw. 075;
076 also equipped with unit-mounted
manual oil pump.
19 cm
3
/min at 6000 rpm
7 cm
3
/min at 6000 rpm
0.551itre
1.6 Weights
1. 7 Special Accessories
7
Model Model
Dry weight with 53 em bar and chain : 051 AVE
11 .2 kg
075 AVE; 076 AVE
11.7 kg
STIHL repair kit 051 (050); 075:
STIHL repair kit 051 ; 075; 076:
Gasket set 051 (050):
Gasket set 075; 076:
Decompression valve for 051 :
Rewind starter:
1111 900 5000 (With friction shoe)
1111 900 5001 (With pawl)
1111 007 1 050
1111 007 1 051
1111 020 9400
8
2. CLUTCH, CHAIN DRIVE AND
CHAIN BRAKE
2.1 Construction and Operation
2.1 1 Clutch and Chain Sprocket
The transmission of power from the
engine to the saw chain is effected via
a centrifugal clutch. On models equip-
ped w1th a chain brake (Quickstep) the
centrifugal clutch incorporates an iso-
lating clutch which is actuated by the
cham brake.
On Ouickstop machines the hub
screwed to the crankshaft is the clutch
element which absorbs the torque and
acceleration of the crankshaft It is
essential that the hub is always tigh-
tened down to the specified torque.
The clutch spider is supported on the
hub by a needle cage but not connected
to it in any other way. The driving plate
is located on the three lugs of the clutch
spider and can move axially while re-
maining in constant mesh with the
spider. The flat spring between the
spider and driving plate presses the
driving plate against the release plate·
this means that the intemal teeth of the
driving plate are always in mesh with
the teeth of the hub when the cha1n
brake is disengaged, and thus insures
positive transmission of engine torque
to the clutch spider. When the chain
brake is actuated, the release plate
disengages the driving plate from the
hub. The clutch spider and hub can
then rotate independently.
On standard machines the clutch
spider takes over the function of the
hub and must therefore always be
tightened to the specified torque. The
centrifugal clutch has three clutch
Component parts of cha1n brake
1 Cha1n sprocket
2 Clutch
3 Spider
4 Flatspnng
5 Driving plate
6 Needle cage
7 Hub
shoes with pressed-f1tted lin1ngs. The
clutch drum and chain sprocket form a
single unit
When the engine is running at idle
speed the clutch shoes are also in the
idle position because the tension of
the clutch springs is greater than the
centrifugal force. As engine speed
increases centrifugal force presses
the clutch shoes outward against the
clutch drum until positive frictional
contact is made and engine torque
is then transmitted via the chain
sprocket to the saw chain.
The preload and strength of the clutch
springs are designed so that the clutch
shoes begin to make contact with the
clutch drum at an engine speed of
approx. 2700 rpm (engagement
speed). The clutch engages fully
above this speed It is therefore very
important to set the carburetor to the
8 Brake band
9 Tens1on spnng
10 Cam
11 Release plate
12 Lever
13 Hand guard
correct idle speed in order to 1nsure
that the clutch engagement speed 1s
not reached when the engme is
idling
You're Reading a Preview
What's Included?
Lifetime Access
Fast Download Speeds
Online & Offline Access
Access PDF Contents & Bookmarks
Full Search Facility
Print one or all pages of your manual
$31.99
$41.99
Viewed 15 Times Today
Secure transaction
What's Included?
Lifetime Access
Fast Download Speeds
Online & Offline Access
Access PDF Contents & Bookmarks
Full Search Facility
Print one or all pages of your manual
$31.99
$41.99
You are purchasing a comprehensive Service & Shop manual for a Stihl 051 AV Electronic. This manual contains valuable technical information for both professional mechanics and DIY enthusiasts. With a file size of 179MB and 76 pages, this English manual provides detailed guidance on every aspect of your vehicle.
With hundreds of pages, this service manual covers a wide range of topics, including but not limited to:
- Body and exterior
- Electrical and electronic systems
- Audio/Video devices
- Charging system
- Electrical supply system
- Gauges and meters
- Ignition system
- Lighting and signaling systems
- Sensors
- Starting system
- Switches
- Wiring harnesses
- Miscellaneous systems
- Powertrain and chassis
- Engine components and parts
- Engine cooling system
- Engine oil system
- Exhaust system
- Fuel supply system
- Suspension and steering systems
- Transmission system
- Wheels and tire parts
This manual is equipped with numerous illustrations and easy-to-read text to assist you in your repair and maintenance tasks. It also includes a search function for easy navigation and the option to print specific pages as needed.
Rest assured, our service manuals are of excellent quality and are backed by great customer service. Whether you are a professional mechanic or a DIY enthusiast, this manual is an invaluable resource for maintaining and repairing your Stihl 051 AV Electronic.
