Husqvarna Cut-n-Break K 760 Workshop 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, cut ting 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 refe rences 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

2

3

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

3

4

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 be come

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

23

2

12

STARTER5

11

Spring cassette

WARNING!

Handling springs of this type con stitutes

a major risk for eye injuries, especially

when you dismantle a cas sette with a

broken spring!

Always wear protective glasses when

handling the spring cassette!

Dismantling

Dismantle both screws on the spring

cassette.

Press out both catches on the spring

cassette with a screwdriver.

Cleaning

Never take out the spring from the

cassette. If the spring is dirty it can be

blown sufficiently clean with compressed

air. Now apply a light oil on the spring.

Starter pulley

First eliminate the spring force as per the

previous page. Remove the centre screw

and lift off the starter pulley.

Clean the surfaces between the starter

pulley and the spring cassette.

Assembly

Lubricate the hub with grease (arrows).

Preferably also apply some grease around

the starter pulley hub so that the grease

seals against the spring cassette.

Align the starter pulley cut-out with the

end of the spring when assembling. Fit

the centre bolt.

The centre of the starter pulley

The spring in the starter pulley dampens

vibrations. The dust seal above has an O-

ring. The spacer sleeve around the centre

screw is the upper bearing point for the

starter pulley. Check that the spacer sleeve

has not fallen off during reassembly.

12

STARTER 5

Starter pawls

Function

In principle the starter pawls have two positions that are determined by the

centrifugal force generated by the rotation of the flywheel.

When the engine is at a standstill the springs push the starter pawls towards

the centre, which when starting then grip the starter pulley's metal sleeve.

As soon as the engine starts, the starter pawls are thrown out of the starter

pulley's centre to their outer positions.

Consequently it is important for the function that the springs are in full

working order and that the starter pawls do not jam. The starter pawls must

not be lubricated!

Inspection

Check that the springs are in full wor-

king order and that the starter pawls do

not jam. Dismantle and clean if necessary.

Dismantling/assembling

The starter pawls are fitted using a shoul-

der screw. Note the position of the

springs in relation to the flanges on the

flywheel so that they are fitted correctly.

NOTE! Do not forget the washer (A) that

should lie under the starter pawls against

the flywheel.

Assembly

It is important that the spring does not

get caught between the starter pawls and

the flywheel. The follow ing method is

recommended when assembling:

1. Press the spring into position in the

flywheel.

2. Fit the washer.

3. Screw on the starter pawls.

4. Make the simplest of “special tools”:

Bend the end of a thin steel wire and use

this to pull the spring under the starter

pawls to the mount ing on the opposite

side.

Fitting the starter

Do as follows so that the starter pawls

come into the right position against the

starter pulley sleeve: First pull out the

cord about a half meter. Keep this posi-

tion when the starter is set against the

machine and slowly release and the starter

pawls will take on the correct position.

Tighten the four screws on the starter to a

torque of 5–6.5 lbf·ft/7–9 Nm.

A

12

34

IGNITION SYSTEM6

13

Function

The ignition system is fully enclosed and has no moving

parts. It is insensitive to moisture and dirt. The design is

such that the ignition point does not need to readjustment.

Husqvarna K760 has integrated overspeed protection in the

electronic unit that limits the engine's speed to 9,300 rpm.

The ignition system consists of the primary coil (A) and

secondary coil (B) which are both surround ed by the iron

core (C). An electronic digital unit (D) manages the switch

function.

Current is generated in the primary coil when the fly -

wheel's permanent magnet passes the coil and has the voltage

sequence illustrated in the diagram below. (The dashed line

indicates the voltage that should be generated if the current

is not broken.)

The ignition point is determined by the electronic unit,

which sense the voltage variation in the primary coil and

breaks the current at the right level, at the same time the

engine piston is just below the upper turning point. At the

breaking instant the voltage in the primary coil rises from

5 V (volt) to approximately 200 V through induction. At the

same time a high voltage, approximately 20,000 volt, is

transformed in the secondary coil to the spark plug.

Electronic

circuit

breaker

STOP

control

Volts

+

-

0

Ignition

point

SN

1�

�

1�

�

A�

�

D�

�

B�

�

C�

�

2�

�

2�

�

3�

�

3�

�

Spark plug

The spark plug's electrode gap should be

.02 in./0.5 mm.

The electrodes should be free of soot

deposits and oil. Brush clean with a wire

brush.

A convex centre electrode and a worn

side electrode impair the ignition charac-

teristics. Replace the spark plug.

Spark plug

The electrode gap scale should

be .02 in./0.5 mm.

Ignition module

The ignition module components are fully enclosed to withstand external

effects. Individual components cannot be replaced.

The ignition cable, the contact unit to the spark plug and the seal on the

ignition module can be replaced.

The ignition module requires no routine service measures. (However, the

distance to the flywheel magnet can be adjusted where necessary.)

Besides the connection to the spark plug there are two connections on the

ignition module. The arrow-marked flat pin connector connects to the stop

switch. The other is the power outlet for machines with OilGuard.

0.5 mm

.02 in.

IGNITION SYSTEM 6

14

Trouble shooting

Examine the ignition system first when

the engine does not start.

Check the ignition spark

Earth the spark plug against the cylinder

by using the spark plug socket to extend

the earth cable as the air duct prevents

direct earthing.

Move the stop button to the operating

position. Pull the starter handle as with

starting.

Do the following if no spark occurs.

Faulty spark plug

Replace the spark plug with the test spark

plug 502 71 13-01. If there is spark now

the spark plug is defective. Replace the

spark plug.

If there is no spark the next step is to

check the ignition lead.

Faulty ignition lead

1, 2. Pull up the rubber seal by the igni-

tion module and unscrew the ignition

lead from this.

3. Insert a pair of pointed pliers in spark

plug connection and pull out the spring

and cable end.

4. If the connection is defective, the igni-

tion lead can be shortened slightly. Make

a new hole in the cable with a awl and fit

the connection spring.

5. The adjoining simple connection can

be used to check that the ignition lead is

not broken. The battery is connected in

series with a test lamp.

Alternatively, a resistance measurement

can be made using a Ohm meter.

Damaged short-circuit cable

Check that the short-circuit cable is in

position. Examine the cable for signs of

wear or damage where it may have

reached the engine body and in doing so

create a short circuit.

Test the stop switch and the cable to

this from the ignition module with one

of the following methods.

502 71 13-01

1

45

23

IGNITION SYSTEM6

15

Replacing the ignition module

The ignition module is secured by two

screws to the engine body.

When assembling the new module, the

flywheel with magnets is turned towards

the ignition module.

Place air gap gauge (.01 in./0.3 mm)

502 51 34-02 against the magnets and fit

the new module in position.

The screws should be tightened to a

torque of 6.6–8.1 lbf·ft/9–11 Nm.

502 51 34-02

Removing the stop switch

1. Remove the cable lug and the screw.

2–4. Bend the control to the left with a

large screwdriver and pull the switch to

the right side first.

Mounting the stop switch

1. Press the switch to the snap lock.

2. Press in the right side.

3. Press in the left side to ensure the snap

fastener locks the switch. Fit the screw

and cable lug.

Test of short circuit cable and

stop switch

Try using a measuring instrument or the

following simple solution: Connect a

battery in series with a test lamp to the

short-circuit cable and engine body.

Observe the test lamp while testing the

function of the stop switch. With the

stop switch in operating position the

lamp must be out.

If the lamp is on – check first that the

short circuit cable insulation is not

damaged and is providing contact to the

engine body. Now check the stop switch.

1

3

1

2

4

2 3

16

FLYWHEEL 7

Removal

Unhook the springs and place

the start hooks in their outer

positions.

The arrows mark the place for

the tool below.

Tool 502 51 49-02

A special tool from Husqvarna is

required to dismantle and assemble the

flywheel. The tool fits virtual all fly -

wheels on Husqvarna power cutters.

Tool 502 51 49-02

The special tool is used to

dismantle and assemble the

flywheel.

Centre with socket

Place a 13 mm socket on the flywheel's

centre screw. Push aside the start hook's

springs so that they are not squeezed

between the socket and flywheel.

Centre with socket

Place a 13 mm socket on the

centre screw. Make sure the

springs do not get caught up.

Centre the tool

Choose a suitable screw, supplied with

the tool, and mount the plate.

Centre the tool

Fit the plate.

Remove the centre nut

Use the special tool's handle to lock the

flywheel rotation and remove the nut

and washer.

Remove the nut

Removal

Remove the starter and lower air duct.

The start hooks must be in “running

mode” to be able to mount the screws to

the tool below, marked by arrows.

Unhook the springs and place the start

hooks in their outer positions.

502 51 49-02

17

FLYWHEEL7

Check the keyway and key

Note that the key in the flywheel

is cast and can not be replaced.

If the key is damaged the fly-

wheel must be replaced.

Check the keyway and key

Note that the key in the flywheel is cast

and can not be replaced. If the key is

damaged the flywheel must be replaced.

As the ignition point is determined by

the position of the flywheel on the crank-

shaft, components must have exactly the

right placement in relation to each other.

Only the force of the centre nut is not

sufficient to hold the flywheel in the

right position.

Fit the flywheel

The crankshaft and the centre of the fly-

wheel must be free from grease when

assembling.

Align the key in the fly wheel with the

keyway on the crankshaft. Fit the washer

and nut.

Tightening torque

18–22 lbf·ft/25–30 Nm

Use a torque wrench to tighten the nut.

Remove the tool and hook up the

springs on the start hooks.

Fit the flywheel

The crankshaft and the centre of

the flywheel must be free from

grease when assembling.

Align the key in the fly wheel

with the keyway on the crank-

shaft. Fit the washer and nut.

Tightening torque

18–22 lbf·ft/25–30 Nm

Use a torque wrench to tighten

the nut.

Mount the screw press

Mount the screw press in the centre and

screw it down far enough to ensure it is

secure in the plate.

Mount the screw press

Press off the flywheel

Lock the outer socket with a wrench and

screw in the centre screw until the fly-

wheel releases.

Hint: If the flywheel is sitting very firm-

ly, you can knock lightly with a hammer

on the screw to the flywheel to release. At

the same time lift the machine slightly

from the base by the tool handle.

Press off the flywheel

Lock the socket and screw in the

centre screw.

18–22 lbf·ft/25–30 Nm

AIR FILTER 8

18

Function

Husqvarna Active Air Filtration is a filter system that sig-

nificantly improves the K760 model. The improved centrifugal

cleaning has now made the previous plastic foam filter obsolete.

1. The centrifugal cleaning is the first step in the air clea-

ning of the inlet air. The fins and inlet nozzle are newly designed

and the amount of dust per volume of air has been halved com-

pared to previous models.

The fins on the flywheel supply the cylinder with cooling air

while they are also the active part in the centrifugal cleaning of

the engine's inlet air. An inlet nozzle is fitted next to the fins on

the flywheel. The centrifugal force means that large particles do

not follow the curved air currents to the nozzle, but are thrown

to the outside of the nozzle. Only very small dust particles manage

to curve with the air currents to the inlet.

2. The paper filter now has a more dust absorbing surface

area compared to its predecessor K750. The distribution chamber

in front of the paper filter spreads the air flow evenly over the

filter surface.

3. Service filter's sole task is to prevent foreign objects from

entering the engine during service work. The service filter should

only be replaced if it is damaged.

Filter service

1. Centrifugal cleaning

The inlet duct should be inspected and any deposits removed in

connection with filter replacement. Dust from dry cutting is

blown clean using compressed air. Material from wet cutting nor-

mally needs to be scraped off mechanically.

Make sure the rubber seal on the upper air duct cover is intact

and that it is correctly fitted in the cylinder cover!

2. Paper filter

The paper filter must not be cleaned but replaced, whenever

necessary, with a new filter. The replacement frequency is highly

dependent on the material to be cut and if the cutting is to be

wet or dry. Change the filter when the machine starts to lose

power.

Observe extreme caution when the filter is removed to ensure

that no dust particles fall down through the service filter.

Removal of waste and cleaning of the gasket around the service

filter is best done using a vacuum cleaner.

Also blow out the dust collected in the distribution chamber.

3. Service filter

The service filter only needs replacing if damaged.

2

3

115 32 40-26

1

19

115 32 40-26

FUEL SYSTEM9

Fuel filter

Dismantle the filler cap.

Catch the fuel hose with the

help of tool 502 50 83-01.

Fuel filter

Dismantle the filler cap and pull out the

section holding the filler cap in position

when fuelling.

Catch the fuel hose with the help of tool

502 50 83-01.

Pull out the hose a little through the

tank fill hole and pull out the fuel filter.

Check that the filter is not cracked or in

any other way defective. Fouled filters

must not be cleaned but replaced with

new ones. First lift up the metal ring

whereupon the hose can be pulled off the

filter.

If the filter is heavily fouled, this may be

due to the machine being filled with a

contaminated fuel. Drain the fuel and

filter when refilling.

Pull out the fuel filter. Check

that the filter is not cracked or

in any other way defective.

Fouled filters are replaced with

new ones.

Heavily fouled filters can be due

to fuelling with contaminated

fuel. Check and filter the fuel if

necessary.

Fuel hose

Pressure tester 501 56 27-01

Use the pressure tester 501 56 27-01 to

test the tightness of the fuel hose.

The pressure tester is supplied with an

adapter for small hose sizes, this should

be used on the fuel hose. Make the hose

between the adapter and the pressure

tester as short as possible.

Fuel hose

Pressure tester

Use the pressure tester to test

the tightness of the fuel hose.

Connect the adapter to the

pressure tester with a short hose.

Pressure test the fuel hose

Pump up the pressure to approxi mately

7 psi/50 kPa. A falling pres sure indicates

that the fuel hose leaks, the connection

to the carburettor leaks or the carburet-

tor is defective.

Pressure test the fuel hose

Pump up the pressure to

approximately 7 psi/50 kPa.

Move to the next test if the

pressure drops.

501 56 27-01

502 50 83-01

Exclude the fuel hose as the

cause of leakage

Remove the carburettor unit. Plug the

hose by the carburettor and redo the

pressure test. If the hose is in tact, the

carburettor must be checked.

Exclude the fuel hose as

the cause of leakage

Remove the carburettor unit.

Plug the hose by the carburettor

and redo the pressure test.

20

Filter – functional test

Pull off the rubber hose with the sintered

filter. Blow through the hose and note

whether the air can pass through slowly.

Filter replacement

A clogged filter should not be blown

clean but replaced. Use a pin punch to

push out the filter out of the hose.

Push in a new filter.

Filter - functional test

Observe whether the air can

slowly pass through the filter.

Filter replacement

Clogged filters should not be

blown clean but replaced.

FUEL SYSTEM 9

Tank venting

The tank vent has a non-return valve that permits air to enter the tank, but

prevents fuel from running out. The sintered metal filter permits air to pass

slowly.

Fault indication

Blocked tank vent is shown as follows: As the fuel tank is emptied during use

an underpressure is created in the tank, which reduces the fuel supply – the

machine lacks power. When filler cap is opened air suction is audible.

Changing the fuel hose

Loosen the cable lug to the stop switch to gain better access to the fuel hose.

Remove the hose from the tank at the same time as it is fed down through the

hole in the carburettor compartment

little by little.

The new hoses is fed down into the tank from the carburettor compartment.

Feed down the hose by hand or with the help of a pair of pliers. Greasing the

hoses facilitates assembly.

Note how the fuel hose is suspended on the tank unit when assembling.

The snap lock for the hose holder can be opened with a small screwdriver

from the outside of the tank unit.

Do not forget to refit the cable lug on the stop switch!

Dismantling

The carburettor unit must be dismantled

to gain access to the tank vent.

Remove the choke control.

Press the air vent unit backwards and

push it up with some pliers.

Dismantling

Dismantle the carburettor unit

and choke control.

Press up the air vent unit with a

pair of pliers.

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Husqvarna Cut-n-Break K 760 Workshop Manual

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Husqvarna Cut-n-Break K 760 Workshop Manual

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