Husqvarna 525HE3 Instruction manual

Workshop manual
525HE3, 525HE4
English
1371 - 001 - 02.07.2020

Contents
1 Introduction
1.1 Document description............................................ 3
1.2 Target group...........................................................3
1.3 Revisions................................................................3
1.4 Safety..................................................................... 3
1.5 Servicing tools........................................................3
2 Safety
2.1 Safety definitions....................................................4
2.2 General safety instructions.....................................4
2.3 Special safety instructions......................................4
2.4 Symbols on the product......................................... 4
3 Prepare and do servicing on the product
3.1 Maintenance schedule........................................... 6
4 Servicing data
4.1 Servicing data ....................................................... 7
5 Servicing tools
5.1 Servicing tools .....................................................11
6 Repair instructions
6.1 Product overview for repair instructions .............. 13
6.2 To clean and examine the product parts..............14
6.3 Covers..................................................................14
6.4 Starter.................................................................. 14
6.5 Muffler.................................................................. 17
6.6 Air filter................................................................. 17
6.7 Carburetor............................................................ 18
6.8 Shaft.....................................................................23
6.9 Clutch and clutch drum........................................ 23
6.10 Flywheel............................................................. 25
6.11 Ignition system................................................... 26
6.12 Cylinder and piston............................................ 28
6.13 Crankshaft and crankcase................................. 30
6.14 Fuel tank............................................................ 33
6.15 Handle and throttle trigger..................................35
6.16 Bevel gear.......................................................... 37
6.17 Gearbox............................................................. 38
6.18 Cutting unit......................................................... 39
7 Troubleshooting
7.1 Troubleshooting................................................... 40
8 Technical data
8.1 Technical data......................................................44
21371 - 001 - 02.07.2020

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 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.
1.3 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.
1.4 Safety
WARNING: All personnel that repair or do
servicing on the product must read and
understand the safety instructions in this
workshop manual.
1.5 Servicing tools
The manual gives information about necessary servicing
tools. Always use original tools from Husqvarna.
1371 - 001 - 02.07.2020 Introduction - 3

2 Safety
2.1 Safety definitions
Warnings, cautions and notes are used to point out
specially important parts of the manual.
WARNING: Used if there is a risk of injury or
death for the operator or bystanders if the
instructions in the manual are not obeyed.
CAUTION: Used if there is a risk of damage to
the product, other materials or the adjacent area
if the instructions in the manual are not obeyed.
Note: Used to give more information that is necessary in
a given situation.
2.2 General safety instructions
WARNING: Read the warning instructions that
follow before you use the product.
The service center that repairs the product must have
safety devices that obey local regulations. Warnings and
cautions are used to point out specially important parts
of the workshop manual.
2.3 Special safety instructions
• When you use compressed air, do not point the
airflow in the direction of your body. Air can go into
the blood circulation and kill you.
• Use eye protection when you do work on springs
that have tension.
• Do not use accessories that are not approved by the
manufacturer. Do not do changes that are not
approved by the manufacturer. This can cause injury
or death to the operator or other persons.
• Always use original spare parts and accessories.
• Use approved hearing protection. Noise from the
product can result in permanent hearing loss.
2.4 Symbols on the product
Stop.
This product can be dangerous and cause
serious injury or death to the operator or
others. Be careful and use the product
correctly.
Read the operator's manual carefully and
make sure that you understand the
instructions before you use this product.
Use a protective helmet in locations where
objects can fall on you. Use approved
hearing protection. Use approved eye
protection.
Always wear approved protective gloves.
Use stable boots with non-slip soles.
Stop the product fully before you touch the
cutting tool.
Keep all parts of your body away from the
hot surfaces.
Fuel.
Choke.
Air purge bulb.
Idle adjustment screw.
High speed needle.
Low speed needle.
There is no electrical insulation in this
product. If the product touches or comes
near high voltage power lines, it can
cause serious injury or death to the
operator. Electricity can move between
different objects by a curve. The higher
the voltage, the longer the electricity can
move. Electricity can also move through
branches and other objects, especially if
the object is wet. Always keep a distance
at a minimum of 10 m/33 ft between the
product and high voltage power lines.
Make sure that the power is off before you
start the work near the power lines. Keep
a distance at a minimum of 15 m/50 ft to
other persons or animals during the
operation.
4 - Safety 1371 - 001 - 02.07.2020

This product applies with the applicable
EC Directives.
Noise emissions to the environment
according to European Directive
2000/14/EC and New South Wales
legislation “Protection of the Environment
Operations (Noise Control) Regulation
2017”. Noise emission data can be found
on the machine label and in the Technical
data chapter.
yyyywwxxxxx The rating plate shows the serial number. yyyy is the production year and ww is the
production week.
Note: Other symbols/decals on the product refer to
special certification requirements for some markets.
1371 - 001 - 02.07.2020 Safety - 5

3 Prepare and do servicing on the product
3.1 Maintenance schedule
Maintenance Daily Weekly Monthly
Clean the external surface. After each operation.
Clean the muffler, exhaust pipe and engine from leaves, dirt and unwanted lubri-
cant. After each operation.
Make sure that the cutting unit does not move at idle speed. X
Do a check of the stop switch. X
Examine the cutting unit for damages and cracks. Replace if it is damaged. X
Do a check of the throttle trigger lockout and the throttle trigger. X
Examine the engine, the fuel tank and the fuel lines for leaks. X
Tighten nuts and screws. X
Examine the fuel filter for contamination and the fuel hose for cracks and other
defects. Replace if necessary. X
Examine the starter and the starter rope for damages. X
Clean the air filter. Replace if it is necessary. X
Examine the vibration damping units for damages and cracks. X
Examine the spark plug, refer to To examine the spark plug on page 26 . X
Clean the cooling system. X
Clean the external surface of the carburetor and the area around it. X
Clean or replace the spark arrester mesh. X
Clean the inner surface of the fuel tank. X
Make sure that the gearbox is filled with grease. X
6 - Prepare and do servicing on the
product
1371 - 001 - 02.07.2020

4 Servicing data
4.1 Servicing data
▲ Lubricate with chain oil.
● Lubricate with grease.
T27
6 - 8 Nm
T276 - 8 Nm
T27
3 - 4 Nm
T271.6 - 2.5 Nm
1.6 - 2.5 Nm
15 - 20 Nm
T27
4 - 5 Nm
T273 - 4 Nm
T274 - 5 Nm
T27
9 - 10 Nm
T275 - 7 Nm
T277 - 8 Nm
T27
5 - 7 Nm
T27
7 Nm
5 - 7 Nm
T276 - 8 Nm
2 - 3 Nm
1371 - 001 - 02.07.2020 Servicing data - 7

T27
6 - 8 Nm
T27
5 - 6 Nm
T272 - 2.5 Nm
T277 - 8 Nm
T272 - 2.5 Nm
T270.5 - 1.5 Nm
T274 - 6 Nm
T277 Nm
T276 - 7 Nm
2 - 3 Nm
2.5 - 4.5 Nm
8 - Servicing data 1371 - 001 - 02.07.2020

T276 - 9 Nm
6 - 8 Nm
1371 - 001 - 02.07.2020 Servicing data - 9

T271.5 - 2.5 Nm
T273 - 4 Nm
10 - Servicing data 1371 - 001 - 02.07.2020

5 Servicing tools
5.1 Servicing tools
0.3
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15
17 18 19
16
20
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21
Item Description Use to Article number
1 Piston stop Lock the piston 522 43 18-01
2 Carburetor adjustment tool Adjust the carburetor 597 10 85-01
3 Torx T27 Remove and attach torx screws 502 71 27-03
4 Piston assembly kit Assemble the piston 502 50 70-01
5 Starter pawl puller Remove the starter pawl assembly 581 96 55-01
6 Crankshaft assembly sleeve Protection for the seal ring 577 90 21-01
7 Snap ring pliers Remove snap rings N/A
8 Combination wrench N/A 575 73 82-01
9 Grease Lubricate the parts in the bevel gear
and the gearbox
587 29 99-01
10 Ignition tester Spark strength check 501 97 64-01
11 Pressure gauge Test pressure 531 03 06-23
12 Ignition cable pliers Repair the ignition cable 502 50 06-01
13 Removal tool for piston pin Remove the pin from the piston 502 02 61-02
14 Assembly fixture Hold the product in position during
maintenance
502 51 03-01
15 Mandrel Remove the bearing from the crank-
case
505 38 17-09
16 Fuel filter hook Remove fuel filter 502 50 83-01
17 Air gap gauge Measure the distance between the fly-
wheel and the ignition module
502 51 34-02
18 Air filter oil Clean the air filter 531 00 60-76
19 Grease Lubricate the parts in the bevel gear
and the gearbox
588 81 48-01
20 Tachometer To measure RPM 502 71 14-01
21 Flywheel puller Remove the flywheel rotor 510 13 89-01
12 - Servicing tools 1371 - 001 - 02.07.2020

6 Repair instructions
6.1 Product overview for repair instructions
9
1
11
6
10
8
3
2
5
7
4
12
13
15
14
16
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1. Starter housing
2. Muffler
3. Flywheel
4. Ignition module
5. Clutch assembly
6. Fuel tank
7. Carburetor
8. Clutch cover
9. Cylinder cover
10. Air filter cover
11. Bumper
12. Clutch drum
13. Blades
14. Gearbox
15. Bevel gear
16. Throttle handle
6.2 To clean and examine the product parts
• Clean and examine all parts fully. You find more
instructions in the chapter for each part if special
tools or procedures are necessary.
• Replace damaged or defective parts.
• Always use original spare parts.
6.3 Covers
6.3.1 To remove and install the air filter cover, the
muffler cover and the cylinder cover
1. Turn the knob (A) counterclockwise and remove the
air filter cover (B).
A
B
C
2. Remove the screw (C).
3. Remove the 2 screws (D) and the muffler cover (E).
E
D
4. Remove the screw (F) and the cylinder cover (G).
F
G
5. Install in the opposite sequence.
6.4 Starter
6.4.1 To remove and install the starter unit
1. Remove the 3 screws that hold the starter unit.
2. Remove the starter unit.
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3. Install in the opposite sequence.
6.4.2 To install the recoil spring in the starter pulley
WARNING: Use protective glasses. The recoil
spring can eject and cause injury.
1. Put the outer flange of the recoil spring into the slot
in the starter pulley.
2. Push the recoil spring into the starter pulley and turn
the starter pulley to wind the recoil spring. Continue
until the recoil spring is fully installed in the starter
pulley.
6.4.3 To clean and examine the starter unit
• Clean all components.
• Examine the starter rope. Replace the starter rope if
it is damaged.
• Examine the starter pulley. Replace damaged parts.
• Make sure that the start pawls on the starter pawl
assembly are not damaged. Make sure that the
starter pawl springs on the starter pawl assembly
are attached correctly and move freely.
• Lubricate the starter pawls on the starter unit.
• Lubricate the starter spring.
6.4.4 To disassemble and assemble the starter unit
1. Remove the inner cover in the starter housing. Use
a flat screwdriver.
2. Turn the starter pulley to decrease the spring
tension. Lift up the starter rope on the starter pulley
and let it rotate clockwise. Slow the rotation with
your thumb. Remove the screw in the center of the
starter pulley. Carefully lift the starter pulley up from
the starter housing.
3. Clean parts before assembly. Replace the return
spring, starter pulley and started rope if necessary.
1371 - 001 - 02.07.2020 Repair instructions - 15

4. Lubricate the spindle with Husqvarna grease and
install the starter pulley. Tighten the screw.
Assemble a new starter rope. Move it into the starter
pulley slot and out through the notch in the starter
housing. Make sure that the knot on the end of the
rope is as small as possible.
5. Put the starter rope handle on the starter rope.
6. Adjust the tension of the return spring. Pull the
starter rope out fully and slow the starter pulley with
your thumb. Lift the rope into the notch on the starter
pulley. Turn the starter pulley counterclockwise, 6
turns. Examine the spring tension. The starter pulley
must be possible to move a half turn while the
starter rope is fully extended.
6.4.5 To replace the starter pawl assembly
1. Remove the starter unit.
2. Remove the spark plug cap and the spark plug. Put
a piston stop in the spark plug hole to lock the axle.
3. Use the removal tool to remove the starter pawl
assembly. Refer to Servicing tools on page 11 .
4. Examine the starter pawl assembly.
a) Clean the starter pawl assembly if it is dirty.
16 - Repair instructions 1371 - 001 - 02.07.2020

b) Remove the snap ring that holds the starter
pawl. Remove the starter pawls and springs.
c) Replace the parts in the starter pawl assembly if
they are damaged.
5. Assemble the starter pawl assembly in the opposite
sequence to how it was disassembled.
6. Attach the starter pawl assembly to the crankshaft.
7. Remove the piston stop and install the spark plug
and spark plug cap.
8. Attach the cylinder cover.
9. Attach the starter unit.
6.5 Muffler
6.5.1 To remove and install the muffler
1. Remove the muffler cover. Refer to To remove and
install the air filter cover, the muffler cover and the
cylinder cover on page 14 .
2. Remove the 2 screws (A), the muffler (B), and the
muffler gasket (C).
A
B
C
3. Remove the screw (D).
E
D
4. Push the spark arrester (E) to the side to remove it
from the muffler.
5. Install in the opposite sequence.
6.5.2 To clean and examine the muffler
1. Clean all components. Clean the contact surfaces of
the gasket, the heat deflector and the cylinder.
2. Examine the spark arrester for damage.
3. Examine the muffler for damage.
4. Examine the gasket for damage.
5. Replace all damaged parts.
6.6 Air filter
6.6.1 To remove and install the air filters
1. Remove the air filter cover. Refer to
To remove and
install the air filter cover, the muffler cover and the
cylinder cover on page 14 .
2. Remove the 2 air filters.
3. Install in the opposite sequence.
6.6.2 To clean and examine the foam air filter
CAUTION: Do not use compressed air to clean
the foam air filter.
1371 - 001 - 02.07.2020 Repair instructions - 17

WARNING: Use protective gloves.
1. Remove the foam air filter. Refer to To remove and
install the air filters on page 17
.
2. Clean the foam air filter with warm soap water.
Note: Use Husqvarna cleaning agent. Refer to
Servicing tools on page 11 .
Note: Replace the foam air filter if it cannot be fully
cleaned. Always replace a damaged foam air filter.
3. Dry the foam air filter.
4. Put the foam air filter in a plastic bag and put 1
tablespoon of air filter oil into the plastic bag.
Note: Use Husqvarna air filter oil. Refer to Servicing
tools on page 11 .
5. Rub the plastic bag to supply the oil equally across
the foam air filter.
6. Push the unwanted oil out of the foam air filter while
in the plastic bag.
7. Clean the inner surface of the air filter cover. Use
compressed air or a brush.
8. Install the foam air filter. Refer to To remove and
install the air filters on page 17 .
6.6.3 To clean and examine the felt air filter
1. Remove the felt air filter. Refer to To remove and
install the air filters on page 17 .
2. Clean the felt air filter with compressed air.
CAUTION: Replace the felt air filter if it
cannot be fully cleaned. Always replace a
damaged felt air filter.
3. Clean the inner surface of the air filter cover. Use
compressed air or a brush.
6.7 Carburetor
6.7.1 To disconnect and connect the throttle cable
1. Remove the air filter cover. Refer to To remove and
install the air filter cover, the muffler cover and the
cylinder cover on page 14 .
2. Push out the throttle cable stop (A) from the slot in
the throttle cable swivel (B).
A
B
3. Install in the opposite sequence.
6.7.2 To remove and install the carburetor
1. Remove the air filter. Refer to To remove and install
the air filter cover, the muffler cover and the cylinder
cover on page 14 .
2. Close the choke valve and use compressed air to
remove dirt around the carburetor.
3. Disconnect the throttle cable from the carburetor.
Refer to To disconnect and connect the throttle
cable on page 18 .
4. Remove the 2 screws (A).
A
D
C
E
B
5. Remove the air filter holder (B), the carburetor
gasket (C), the carburetor (D) and the insulator
gasket (E).
6. Disconnect the fuel hoses from the carburetor and
remove the carburetor.
7. Install in the opposite sequence.
18 - Repair instructions 1371 - 001 - 02.07.2020

6.7.3 Overview of the carburetor
1
2
3
4
5
6
7
24
25
26
27
28
29
30
32
33
35
34
31
8
9
10
11
16
17
20
12
13 14
15
18
19
21
22
23
36
37
1. Screw
2. Fuel pump cover
3. Spring
4. Idle speed adjustment screw
1371 - 001 - 02.07.2020 Repair instructions - 19

5. Fuel pump gasket
6. Fuel pump diaphragm
7. Fuel screen
8. Screw
9. Metering cover
10. Metering diaphragm
11. Metering gasket
12. Metering lever
13. Metering lever pin
14. Needle valve
15. Screw
16. Metering lever spring
17. Throttle cable swivel
18. Washer
19. Snap ring
20. Throttle shaft
21. Throttle valve plate
22. Screw
23. Return spring for throttle shaft
24. E-clip
25. Throttle lever
26. Screw
27. Choke shaft
28. Choke valve plate
29. Screw
30. Friction ball
31. Spring
32. Speed needle spring
33. High speed needle
34. Low speed needle
35. Needle cap
36. Piston
37. Spring
6.7.4 To disassemble and assemble the carburetor
Clean all parts and examine them for wear and damage.
Replace worn or damaged parts.
1. Remove the carburetor. Refer to To remove and
install the carburetor on page 18 .
2. Remove the screw (A).
A
B
E
C
D
3. Remove the fuel pump cover (B), the fuel pump
gasket (C), and the fuel pump diaphragm (D).
4. Remove the fuel screen (E).
20 - Repair instructions 1371 - 001 - 02.07.2020