Husqvarna K 770 OilGuard Instruction manual

Workshop manual
K770 Vac & Dry Cut
English
701 - 002 -

Contents
1 Introduction
1.1 Document description............................................ 3
1.2 Outline....................................................................3
1.3 Target group...........................................................3
1.4 Revisions................................................................3
1.5 Safety..................................................................... 3
1.6 Servicing tools........................................................3
2 Safety
2.1 Safety definitions....................................................4
2.2 General safety instructions.....................................4
2.3 Symbols on the product......................................... 4
3 Servicing data
3.1 Symbols in the diagrams........................................5
3.2 Tightening torques K770 Vac/Dry Cut....................6
3.3 Tightening torques K770 Vac/Dry Cut....................7
3.4 Tightening torques K770 Dry Cut...........................8
3.5 Tightening torques K770 Vac.................................9
3.6 Tightening torques K770 Dry Cut.........................10
3.7 Tightening torques K770 Vac...............................11
4 Servicing tools
4.1 Servicing tools overview.......................................12
4.2 Servicing tools overview.......................................13
4.3 Servicing tools overview.......................................14
5 Product overview for repair and servicing
5.1 Product overview Dry Cut.................................... 15
5.2 Product overview Vac.......................................... 16
5.3 To disassemble into basic modules..................... 17
6 Repair and servicing
6.1 Starter.................................................................. 24
6.2 Ignition system..................................................... 27
6.3 Flywheel............................................................... 31
6.4 Air filter................................................................. 32
6.5 Fuel system..........................................................34
6.6 Carburetor............................................................ 36
6.7 Decompression valve...........................................44
6.8 Cylinder and piston.............................................. 46
6.9 Piston wear.......................................................... 49
6.10 To assemble the piston...................................... 50
6.11 To assemble the cylinder................................... 51
6.12 Crankcase.......................................................... 51
6.13 Clutch................................................................. 57
6.14 Cutting head.......................................................60
6.15 Gearbox............................................................. 62
6.16 Fan - Dry Cut .....................................................65
6.17 Dust bag - Dry Cut............................................. 70
6.18 Throttle trigger and throttle lock......................... 72
6.19 OilGuard - Dry Cut............................................. 73
7 Troubleshooting
7.1 Engine does not start........................................... 75
7.2 Engine stops during operation - no sparks...........76
7.3 Engine stops during operation............................. 76
7.4 Weak output or change of speed......................... 77
7.5 Other engine problems.........................................77
7.6 Dust......................................................................78
8 Wiring diagram - Dry Cut
8.1 Wiring diagram OilGuard......................................79
2701 - 002 -

1 Introduction
1.1 Document description
This manual gives a full description of how to do
maintenance and repair on the product. It also gives
safety instructions that the personnel must obey.
1.2 Outline
This manual is for K770 Vac and Dry Cut. Most chapters
are applicable to the two models. The chapters that are
applicable for only one model has that model name
included in the title.
1.3 Target group
This manual is for personnel with a general knowledge
of how to do repair and do servicing. All personnel that
do repair or do servicing on the product must read and
understand the manual.
1.4 Revisions
Changes to the product can cause changes to the
maintenance work and spare parts. Separate
information is sent out for each change.
Read the manual together with all received information
about changes to maintenance and spare parts for the
product.
1.5 Safety
WARNING: All personnel that repair or do
servicing on the product must read and
understand the safety instructions in this
workshop manual.
1.6 Servicing tools
The manual gives information about necessary servicing
tools. Always use original tools from Husqvarna.
701 - 002 - Introduction - 3

2 Safety
2.1 Safety definitions
The definitions below give the level of severity for each
signal word.
WARNING: Injury to persons.
CAUTION: Damage to the product.
Note: This information makes the product easier to use.
2.2 General safety instructions
• Do not repair the product unless you have read and
understood this workshop manual.
• The service center where the product is repaired
must have safety equipment approved by local
bylaws.
• The product is examined and approved only with the
equipment given or recommended by the
manufacturer.
• Prevent health and safety risks. All personnel must
obey laws and requirements when they do the
procedures given in this manual.
• Obey the local waste regulations.
• Always make sure that all nuts and bolts are
correctly tightened.
• Use protective gloves and eye protection. Goggles
must obey the ANSI Z87.1 for US or EN166 for EU
countries.
• When using compressed air, do not point it to your
body. Air can go into the bloodstream.
• Use hearing protection when the engine is started.
• The product can make sparks and cause ignition of
flammable materials.
• Replace all damaged or missing warning symbol
decals.
• Gasoline and its fumes are poisonous.
• Gasoline can cause damage to the eyes and the
skin.
• Gasoline can cause breathing problems.
• Gasoline is flammable.
2.3 Symbols on the product
WARNING: Careless or incorrect use can
result in injury or death to the operator or
others.
Read the manual carefully and make sure
you understand the instructions before
using the product.
Always put on personal protective
equipment:
• Hearing protection
• Protective goggles or a visor
• Breathing mask.
This product in compliance with applicable
EC directives.
WARNING! Dust from cutting can cause
breathing problems. Use breathing
protection. Do not breathe exhaust fumes.
Always make sure there is good airflow.
WARNING! Sparks from the cutting blade
can cause a fire in materials such as,
gasoline, wood, fabric and dry grass.
WARNING! Kickbacks can be sudden,
fast and can cause injuries. Read and
understand the instructions in the manual
before using the product.
Make sure the cutting disc is not
damaged.
WARNING! Do not use circular saw
blades.
Note: Other symbols/decals on the product refer to
special certification requirements for some markets.
4 - Safety 701 - 002 -

3 Servicing data
3.1 Symbols in the diagrams
Tightening torque, Nm
701 - 002 - Servicing data - 5

3.2 Tightening torques K770 Vac/Dry Cut
3-5
4-6
4-6
4-6
2,0
7-9
3-5
4-6
6 - Servicing data 701 - 002 -

3.3 Tightening torques K770 Vac/Dry Cut
11-12
10-12
5-7
11-13
11-13
11-13
7-9
17-23
701 - 002 - Servicing data - 7

3.4 Tightening torques K770 Dry Cut
30
8-22
4
4-6
8-10
25
25-30
8-10
1-2
9-11
2-4
1
6-8
4-6
10-12
8-10
8-10
8-10
4-6
6-8
8 - Servicing data 701 - 002 -

3.5 Tightening torques K770 Vac
25
25
8-10
4-6
1-2
8-10
8-10
18-22
4
4
4-6
6-8
701 - 002 - Servicing data - 9

3.6 Tightening torques K770 Dry Cut
13
5
5-6
10-12
6
6
4
3
5-7
5
6-8 25-30
9-11
10-12
10 - Servicing data 701 - 002 -

3.7 Tightening torques K770 Vac
13
6-8
20-25
5
5-6
10-12
6
6
4
3
5-7
5
6-8 25-30
9-11
701 - 002 - Servicing data - 11

4 Servicing tools
4.1 Servicing tools overview
0,3 mm
1 2 3
4 5 6
7 8 9
Po-
si-
tion
Designation Used for Order No./
Source
1 Air clearance gauge To adjust the air clearance between the ignition module and the fly-
wheel.
502 51 34-02
2 Assembly punch To assemble the sealing rings of the crankshaft in the crankcase. 502 50 82-01
3 Bearing press To disassemble the primary bearing and assemble the crankshaft. 544 10 36-02
4 Bearing press To assemble the primary bearing. 506 37 61-02
5 Bearing puller Remove the primary bearing from the crankshaft. 531 00 48-67
6 Combination wrench General. 506 38 26-01
7 Compression tester To examine the compression in the cylinder. 531 03 16-86
8 Bearing press To disassemble and assemble the clutch drum ball bearing, blade
shaft bearing and the fan bearings.
504 56 79-01
9 Cylinder seal To examine the crankcase for leaks. 544 10 33-01
12 - Servicing tools 701 - 002 -

4.2 Servicing tools overview
10 11 12
13 14 15
16 17 18
Po-
si-
tion
Designation Used for Order No./Source
10 Flywheel puller To disassemble the flywheel. 502 51 49-02
11 Grip plate To divide the crankcase. 544 06 00-02
12 Gudgeon pin punch To disassemble and assemble the gudgeon pin. 505 38 17-05
13 Hose catcher To catch the fuel filter in the tank. 502 50 83-01
14 Kit for piston service To do service on the piston. 502 50 70-01
15 Piston stop To disassemble the clutch. 504 91 06-05
16 Pressing device To disassemble and assemble the blade shaft bearings and axle. 575 96 20-01
17 Pressure tester To examine the carburetor, fuel lines and check valve. 501 56 27-01
18 Pressure tester To examine the crankcase for leaks. 531 03 06-23
701 - 002 - Servicing tools - 13

4.3 Servicing tools overview
19 20 21
22 23 24
26 27
25
Po-
si-
tion
Designation Used for Order No./
Source
19 Puller To disassemble the sealing rings of the crankcase in the crankcase. 504 91 40-01
20 Sealing plug To examine the crankcase for leaks. 503 55 22-01
21 Special screwdriver To adjust the idle speed. 501 60 02-03
22 Tachometer To adjust the idle and maximum speed. 502 71 14-01
23 Test spark plug To do service on the ignition unit. 502 71 13-01
24 Universal puller To disassemble the support washer of the clutch on the crankshaft.
To divide the crankcase.
504 90 90-02
25 Key Torx T27 General. 502 71 27-02
26 Grease To lubricate the gearbox and the fan bearings. 588 81 48-01
27 Internal bearing ex-
tractor
To remove bearings from the gearbox. SKF TMIC 7-28
14 - Servicing tools 701 - 002 -

5 Product overview for repair and servicing
5.1 Product overview Dry Cut
9
17
20
19
13
14
15
18
8
5
4
3
2
76
23 22 21
16
11
10
24
12
25
1
1. Cutting blade
2. Blade guard
3. Front handle
4. Air filter cover
5. Cylinder cover
6. Starter rope handle
7. Starter
8. Belt adjustment screw
9. Lock screws for belt adjustment
10. Rear belt guard
11. Fuel tank
12. Throttle trigger
13. Rear handle
14. Throttle trigger lock
15. Air purge bulb
16. Decompression valve
17. Fan
18. Connection bend
19. Bracket
20. Choke lever
21. Viewing glass for fuel
22. Oil guard button
23. Stop switch
24. Blade guard extender
25. Dust Shield
701 - 002 - Product overview for repair and servicing - 15

5.2 Product overview Vac
5
4
3
2
76
20 12
9
10
11
13
14
15
16
17
18
19
8
22
21
1
1. Cutting blade
2. Blade guard
3. Front handle
4. Air filter cover
5. Cylinder cover
6. Starter rope handle
7. Starter
8. Belt adjustment screw
9. Lock screws for belt adjustment
10. Rear belt guard
11. Fuel tank
12. Throttle trigger
13. Rear handle
14. Throttle trigger lock
15. Air purge bulb
16. Decompression valve
17. Bracket
18. Choke lever
19. Viewing glass for fuel
20. Stop switch
21. Blade guard extender
22. Dust Shield
16 - Product overview for repair and servicing 701 - 002 -

5.3 To disassemble into basic modules
This chapter shows how you can disassemble and
assemble the product in its basic modules.
Dry Cut
Vac
701 - 002 - Product overview for repair and servicing - 17

5.3.1 To remove the starter
1. Loosen the 4 screws on the guard.
2. Remove the starter.
5.3.2 To remove the cutting head Dry Cut
1. Remove the connection bend.
2. Loosen the belt tensioner with the combination
wrench
3. Loosen the nuts and remove the front belt cover .
4. Remove the belt from the pulley and remove the
cutting head.
5. Remove the 3 screws on the rear belt guard.
Remove the guard.
18 - Product overview for repair and servicing 701 - 002 -

5.3.3 To remove the cutting head Vac
1. Loosen the nuts on the cutting head. Loosen the belt
tension with the combination wrench. To loosen the
belt tension, turn the nut to the 0 mark.
2. Loosen the nuts and remove the belt cover.
3. Remove the belt from the pulley and remove the
cutting head.
4. Remove the 2 screws on the rear belt guard.
Remove the guard.
Note: Tightening torque when you assemble: 9–11
Nm.
5.3.4 To remove the fan Dry Cut
1. Remove the cover.
2. Before you remove the fan, make a note of how the
fan belt is put. This is to make it easier to assemble
the fan.
701 - 002 - Product overview for repair and servicing - 19

3. Loosen the 2 screws. Remove the fan.
5.3.5 To remove the air filter
CAUTION: Be careful when the air filter is
removed. Dust particles must not fall down in
the carburetor inlet. Removal of waste is best
done with a vacuum cleaner.
1. Remove the 3 screws and remove the cover.
2. Remove the 2 screws and remove the air filter
holder and the air filter.
20 - Product overview for repair and servicing 701 - 002 -