Husqvarna K 760 OilGuard Instruction manual

HUSQVARNA CONSTRUCTION PRODUCTS
Workshop manual
K 760 & K 760 Cut-n-Break

2
1. LITERATURE 3
2. SPECIAL FUNCTIONAL COMPONENTS 4
3. COMPONENTS – ORIENTATION 5
4. DISMANTLING INTO BASIC MODULES 6
5. STARTER 10
6. IGNITION SYSTEM 13
7. FLYWHEEL 16
8. AIR FILTER 18
9. FUEL SYSTEM 19
10. CARBURETTOR 22
11. DECOMPRESSION VALVE 29
12. CYLINDER/PISTON 30
13. CRANKCASE 36
14. CLUTCH 41
15. CUTTING HEAD 44
16. WET SYSTEM 51
17. HANDLE 52
18. OILGUARD (OPTIONAL) 53
19. K 760 CUT-N-BREAK 54
20. TOOLS 59
CONTENTS Page
HUSQVARNA
K 760
K 760 Cut-n-Break
115 32 40-26

3
LITERATURE1
Workshop Manual
The workshop manual covers virtually all work
in the workshop that involves the K760 and
K760 Cut-n-Break. Some very simple and rather
obvious repair work has been omitted.
Outline
An introductory section with the title
“Dismantling into Basic Modules” shows how
the machine is dismantled into large component
units, for example, the starter, cutting arm, air
filter, etc.
The manual goes on to describes in detail
through the different chapter how work on the
basic modules should be carried out.
This arrangement means that as a mechanic,
at least until you have learnt the basic composi-
tion of the machine, you need to start with the
chapter “Dismantling into Basic Modules” to
then move on to the chapter covering the speci-
fic service work.
Layout – pictures and text
Besides the pictures and illustrations there is
generally two columns of text. The left-hand text
column is a concise and is suitable for experienced
mechanics, the right-hand column gives a more
detailed description and is targeted at mechanics
with less experience of repair work on the power
cutter.
Contents
The manual is divided into numbered chapters
together with chapter headings that are stated in
bold at the top of each page.
The list of contents also has page references to
the start of each chapter.
Spare parts
K760 and K760 Cut-n-Break
The folders include all spares for Husqvarna
K760 and K760 Cut-n-Break.
The folders contain complete exploded
drawings for the whole machine where the
location, spares number and appearance of
each component is easy to identify.
HUSQVARNA CONSTRUCTION PRODUCTS
Workshop manual
K 760 & K 760 Cut-n-Break
“Dismantling into Basic Modules”
“Cutting head” (Example)
115 32 40-26
IPL, K760 Cut-n-Break, 2009-11, 575 66 02-01
K760 Cut-n-Break
Reservdelar
Spare parts
Ersatzteile
Pieces de rechange
Piezas de repuesto
Ricambi
Peças sobresselente
HUSQVARNA CONSTRUCTION PRODUCTS
575 66 02-01
IPL, K760, 2009-12, 574 48 01-02
K760
Reservdelar
Spare parts
Ersatzteile
Pieces de rechange
Piezas de repuesto
Ricambi
Peças sobresselente
HUSQVARNA CONSTRUCTION PRODUCTS
574 48 01-02

SPECIAL FUNCTIONAL COMPONENTS
4
X-Torq®
This engine technology was introduced with
its predecessor K750 under the name Dual
Charge, now renamed to X-Torq.
In addition to the intake from the carbu-
rettor with fuel/air mix there are two chan-
nels for intake of fresh air; the upper chan-
nels as shown in the illustration. By directing
the fuel/air mix and the clean air in separate
flushing ducts in the cylinder, the ratios of
fuel mixed air and clean air can be controlled
to ensure that they vary in different phases of
the engine's work cycle.
Cleaner exhaust and better perfor-
mance
The amount of unburned hydrocarbons (HC)
is reduced by approximately 75 % compared
with a traditional design. The emission values
are now clearly under the provisions of
EPAII.
The effect is higher across the whole rev
range, and the torque in the lower rev range
is now considerably higher.
Carburettor
The carburettor has undergone many detail
improvements and a connection to the fuel
chamber has been added for air purge.
Air purge
The pump has a suction function and is con-
nected to the carburettor's fuel chamber. Air
purge empties the fuel chamber of any air
and tops up the fuel chamber with fuel.
With continued pumping any excess fuel is
returned to the tank.
Lower vibration levels
The air filter system and the carburettor are
mounted in the anti-vibration handle device,
which means lower handle vibrations due to
the larger mass (weight) in the handle device.
The carburettor's position in the anti-vibra-
tion section means the carburettor function is
more stable and there is less wear on the car-
burettor's moving parts.
New filter system
The centrifugal cleaning has been significantly
improved with a new flywheel and modified
design of the air intake. The plastic foam fil-
ter from the previous generation is now dis-
continued.
Friction Retarder
The front belt pulley has an inhibiting
mechanism which comes into effect at low
speeds on the cutting blade.
Torx – T27
Torx screw, with the dimension T27, is used
virtually throughout to simplify the service
process.
Note that the screws may have a smooth or
grooved underside.
2
Torx T27

COMPONENTS – ORIENTATION3
5
Components
1. Cutting blade
2. Blade guard
3. Handle for the blade guard
4. Front handle
5. Air filter cover
6. Cylinder cover
7. Starter handle
8. Starter
9. Combination spanner
10. Belt adjustment screw
11. Lock screws for belt adjustment
12. Rear belt guard
13. Fuel tank
14. Throttle control
15. Rear handle
16. Throttle trigger lock
17. Air purge
18. Decompression valve
19. Water valve with tool attachment
20. Water connector
21. Choke lever
22. Sight glass for fuel
23. Start throttle lock
24. Stop switch
5
4
1
23
6
78
9
10
11
13 12 14
19
20
21
15
16
17
18
24
23
22

Basic modules
This chapter shows how the machine is
built up of basic modules, for example,
the starter, carburettor, air filter system,
etc.
The purpose is to illustrate how you
can easily and effectively dismantle and
assemble the machine in its basic modules.
Service work on a component level, for
example, replacing the starter cord, is
described in detail in respective chapters.
Cutting head
1. Loosen the screws to the cutting head.
(Tightening torque when mounting
18–22 lbf·ft/25–30 Nm.)
2. Loosen the tension of the belt with the
adjuster screw.
3. Detach the hose clip.
4. Remove the screws to the cutting head.
Remove the front belt guard by pushing
it forward.
5. Detach the hose at the water valve.
Lift off the belt from the belt pulley and
remove the cutting head.
6. Loosen the rear belt guard's two screws.
(Tightening torque when mounting
6.6–8.1 lbf·ft/9–11 Nm.)
7. Remove the guard.
DISMANTLING INTO BASIC MODULES 4
6
Starter
1. Loosen the starter's 4 screws.
2. Remove the starter.
12
5
67
12 3
4

1
DISMANTLING INTO BASIC MODULES
4
7
Air filter
1. Loosen the guard's three screws and
remove the guard.
2. Loosen the two screws that hold
the filter bottom.
3. Lift up the filter bottom together with
the filter.
4. Press the filter out of the filter bottom.
Cylinder cover
1. Loosen the four screws on the cylinder
cover.
Press together the rubber seal's collar
so that the cylinder cover can be lifted
off.
2. NOTE! When reassembling the rubber
seal must be drawn up through the cover
and the collar then adjusted to fit
correctly against the cover.
Carburettor
1. The carburettor unit is attached to the
cylinder by a single screw. Loosen the
screw.
2. Lift out the carburettor unit. Detach
the petrol hose and the hose to the “air
purge” from the carburettor.
Tip: Tape the throttle control in the
full throttle position to improve access
to the throttle rod's attachment on the
throttle control.
3. Pull the throttle rod out of the con-
trol.
4. The entire carburettor unit can now be
lifted out.
12
34
2!
34
12

DISMANTLING INTO BASIC MODULES 4
8
Assembly
5. Hook the throttle rod into the valve
arm as illustrated. Lift the carburettor
unit into position and fit the fuel hose.
Press down the throttle rod into throttle
control with the help of a pair of pliers.
6. Align the carburettor's choke arm in
the blue choke control.
7. Fit the carburettor unit. Align the lug
on the flange with the cut-out on the
cylinder. Tighten the screw at the top.
Carburettor compartment
1. Tank venting
This is dismantled by angling the unit
backwards and then pulling it out the
tank.
2. Stop switch
This is secured by a screw in the carburet-
tor compartment.
3. Controls
The controls in the rear handle become
accessible for service once the carburettor
unit has been dismantled.
Air duct
Start by removing the starter, air filter
cover and cylinder cover.
1. Lower air duct
In order for reassembly to be correct,
note how the cable to the stop switch is
mounted in the air duct. Lift the cable
out of its attachment.
2. Engine's earth point
The engine's earth point to the stop
button is placed here.
3. Upper air duct
3.1 Detach the ignition cable at the spark
plug and lift the cable out of its attach-
ment in the cover.
5
1
3
2
6
7!
1
2
3.1

DISMANTLING INTO BASIC MODULES4
9
3.2. Dismantle the three screws on the air
duct cover.
3.3. Lift off the air duct cover.
Muffler
Dismantle the cutting head and the
starter.
1. Dismantle the four screws on the
muffler.
2. Dismantle the muffler.
Fit the gaskets correctly!
3. The insulated fibre gasket should lie
closest to the muffler.
4. Fit the heat shield.
5. The aluminium gasket should lie
against the cylinder.
The screws should be tightened to a
torque of 8.0–9.5 lbf·ft/11–13 Nm.
Vibration dampening
Some service work can be aided by split-
ting the machine by the vibration dampe-
ning element.
Dismantle the air filter unit, cylinder
cover and upper the air duct cover.
Dismantle the screw holding the carbu-
rettor. Dismantle the starter and the air
duct cover. Loosen the cable lug by the
ignition module and unscrew the cable
to the earth point. Pull off the water hose
by the valve.
The engine unit is attached to the
handle unit at three points with the vib-
ration dampening element in the form of
springs. Dismantle the screws located by:
1. The lower section on the flywheel side.
2. The base on the clutch side.
3. The handle loop next to the water
valve.
To gain access to the spring's inner
screw, Torx T27, the tool diameter must
be max. 5 mm. The combination spanner
fits.
1 2
345
123
3.2 3.3

STARTER 5
10
Replacing the starter cord
Dismantle the starter.
Eliminate the spring force from
the return spring
1. Pull out the starter cord approximately
12 in./30 cm. Hold the starter pulley
with your thumb and place the cord in
the cut-out on the starter pulley.
2. Let the starter pulley rotate slowly and
wind up the cord on the metal sleeve.
3. Lift off the cord from the starter
pulley.
Attach the new starter cord
The starter cord should be 45 in./
115 cm long and have a diameter of
.16 in./4 mm.
1. Insert one end of the cord from the
top through the hole in the starter pulley
and then out through the notch for the
cord. Pull out virtually the whole cord
length until sufficient cord remains to tie
a knot as illustrated.
2. Insert the other end through the cover
and on through the handle. Tie a double
knot as illustrated.
Loading the return spring
1. Fit the starter cord in the cut-out.
2. Wind the start cord 4 turns around the
hub and pull out the starter handle and
release so that the cord is wound into the
starter pulley. Repeat the procedure with
3 turns of cord around the hub.
Important check!
Check that the return spring does not act
as an end stop by extending the cord
fully. In this position it should be possible
to turn the starter pulley a least a further
half turn before the spring stops the
movement.
1
1
23
2
12