Husqvarna 241R Instruction manual

Workshop manual
241R 241RJ
English

Starter 1
1
Workshop Manual
Brushcutter, Trimmer
Model 241R, 241RJ
Contents
General recommendations ______________________ 2
1. Starter ___________________________________ 3
2. Electrical system ___________________________ 7
3. Fuel system ______________________________ 13
4. Centrifugal clutch__________________________ 29
5. Angle gear _______________________________ 35
6. Cylinder and piston ________________________ 39
7. Crankshaft and crankcase___________________ 49
8. Tools ___________________________________ 55
9. Technical Data ____________________________ 59
© Husqvarna AB, Sweden 2008

Starter
1
2
General recommendations
Bear in mind:
Do not start the engine without the clutch drum and
driveline fitted as the clutch can become detached and
cause severe personal injury.
Do not touch hot components, e.g. the muffler and clutch
before they have cooled sufficiently to avoid burns.
Avoid getting fuel or oil on your skin or in your mouth.
Use a barrier cream on your hands. This reduces the risk
of infection and makes dirt easier to wash away.
Long term contact with engine oil can represent a health
hazard.
Never start the engine indoors. Exhaust fumes are poiso-
nous!
Wipe up oil spills from the floor immediately to avoid slip-
ping.
Do not use tools that are worn or fit badly, for example on
nuts and bolts.
+ Always work on a clean bench.
+ Always work logically to ensure all parts are fitted cor-
rectly and that nuts and bolts are tightened.
+ Use the special tools where recommended to be able to
carry out the work correctly and efficiently.
Special tools
Some of the work described in the Workshop Manual requires
special tools. In each section where this is necessary there is
a picture of the tool and an order number.
We recommend the use of special tools in order to avoid ex-
pensive damage to parts in question and personal injury and
to provide an efficient repair procedure.
Contact faces and gaskets
Ensure all surfaces are clean and free from gasket residue,
etc. When cleaning use a tool that will not damage the contact
face. Any scratches or unevenness should be removed using
a flat fine cut file.
Sealing rings
Always replace a sealing ring that has been dismantled. The
sensitive sealing lip can easily be damaged resulting in inferior
sealing capacity. Surfaces which the seal shall seal against
must also be completely undamaged. Lubricate the sealing lip
with grease before it is fitted and ensure that it is not damaged
e.g. by shoulders and splines on a shaft. Use tape or a conical
sleeve as protection. It is important that the sealing ring faces
in the right direction for it to act as it is intended.
The workshop used to carry out repairs must be equipped
with safety devices in accordance with local directives.
No one may carry out repairs without first having read and
understood the contents of this Workshop Manual.
The boxes below can be found in appropriate parts of this
manual.
WARNING!
The warning box warns of the risk for
personal injury if the instructions are not
followed.
NOTE!
This box warns of damage to material if the instruc-
tions are not followed.
The machine is type approved for safety in accordance with
applicable legislative demands with the equipment specified
in the Operator’s Manual. The assembly of other equipment
or accessories or spare parts not approved by Husqvarna can
result in the failure to meet these safety demands and that
the person carrying out assembly bears responsibility for this.
Poisonous fumes
When using cleaning agents read the instructions carefully.
Ensure there is good ventilation when handling petrol and
other volatile fluids.
The engine's exhaust fumes are poisonous. Test run the
engine outdoors.
Fire risk
Handle fuel with respect as it is extremely inflammable.
Do not smoke and ensure there are no open flames or sparks
in the vicinity.
Make sure there is a working fire extinguisher close at hand.
Do not try to extinguish a petrol fire with water.
502 51 03-01

Starter 1
3
1
Starter
Contents
Dismantling ___________________________________ 4
Assembly_____________________________________ 5
Replacing the drive dogs_________________________ 6

Starter
1
4
502 50 18-01
502 50 18-01
WARNING!
Protective glasses should be worn when working on the starter to avoid injury to the eyes if,
for some reason, the return spring should fly out.
!
!WARNING!
Wear protective glasses.
The return spring lies tensioned
in the starter and can fly out
and cause personal injury with
careless handling.
Demontering
Remove the 4 screws and carefully swing
down the protective plate so far that the
starter can be lifted out.
The cylinder cover does not need to be
loosened or detached.
NOTE!
Ensure the bushings that guide the starter towards the fuel tank are not lost.
Remove the bolt in the centre of the star-
ter pulley and remove the starter pulley.
Remove the bolt in the centre of the star-
ter pulley. Lift the starter pulley carefully
from the starter cover.
Loosen the spring tension. Loosen the spring tension.
Pull out the starter cord about 30 cm.
Brake the starter pulley with your thumb
and lift the cord as illustrated.
Let the starter pulley rotate backwards
slowly.
Dismantling
Remove the starter from the engine.

Starter 1
5
Assembly
Clean component parts before
assembling.
Replace the return spring/starter pulley
and starter cord, if necessary.
Assemble the starter pulley.
Assemble a new starter cord.
Lubricate the spindle with a little grease
and fit the starter pulley.
Position the washer and tighten the screw.
NOTE!
The return spring and starter pulley
are supplied pre-assembled and
are fitted in the starter housing as a
single unit.
Exercise care when opening the
packaging so that the spring does
not fly out.
NOTE!
New starter cord can be attached
without dismantling the starter!
Assemble the starter handle. Assemble the starter handle.
Tie a double knot on the starter cord and
fold under the free end.
Pull the knot fully into the handle.
Tension the return spring.
Check the spring tension.
Tension the return spring.
Pull out the starter cord completely and
slow the starter pulley with your thumb.
Lift the starter cord up out of the cut-out
on the starter pulley.
Now turn the starter pulley anticlockwise,
6 turns.
For starters with a start assistance spring,
the starter pulley must be turned anti-
clockwise 5 turns.
Check the spring tension. With the starter
cord fully extended it should still be pos-
sible to turn the starter pulley further, at
least a half turn.
Assembly
Clean the component parts and assemble
in the reverse order as set out for dismant-
ling.

Starter
1
6
502 51 49-01
Fit the starter on the engine body.
1. Check that the rubber bushings (A) are
in position in the starter housing.
2. Insert the small tab (B) on the periphe-
ry of the starter under the carburettor
cover and swing the starter in against
the engine body.
3. Press the starter in against the engine
body.
4. Pull the starter handle and check that
the drive dogs engage.
5. Screw on the starter with 4 screws.
Remove the circlip and replace any dama-
ged drive dogs or springs, if necessary.
Remove the circlip holdings the drive dog.
Lift out the drive dog and spring for repla-
cement.
Assemble in the reverse order as set out
for dismantling.
Check that the drive dogs move easily!
Replacing the drive dogs
Dismantle the drive body.
Replacing the drive dogs
Fit the puller 502 51 49-01 on the flywheel
(see chapter 2 ”Electrical system”) and
loosen the drive cup.
NOTE!
The nut is brazed onto the drive
cup.
Do not use, e.g. a pair of slip-joint
pliers to hold the drive cup. It can
easily be deformed so that the
drive dogs cannot move freely.
Note!
Make sure that the rubber support (C) is mounted on the starter. This prevents
vibrations in the tank and starter.

2
7
2
Electrical system
Electrical system
Contents
Checking the ignition spark ___________________10
Dismantling _______________________________12
Assembly_________________________________14

2
8
502 51 91-01
502 71 13-01
Electrical system
The engine is equipped with an electronic ignition system completely without moving parts. Conse-
quently, a faulty component cannot be repaired, but must be replaced by a new component.
The spark in an electronic ignition system has a very short burn time and can therefore be interpre-
ted as weak and can be difficult to see while troubleshooting.
Checking the ignition
spark
Clean the electrodes and check the elec-
trode gap.
Checking the ignition
spark
Remove the spark plug and clean it from
soot deposits with the help of a steel
brush.
Check the electrode gap. It should be 0.5
mm.
Adjust the gap as needed to the correct
value with the side electrode.
If the electrodes are worn more than 50%
the spark plug should be changed.
If the electrodes are worn more than 50%
the spark plug should be changed.
Too large a spark gap entails a great deal
of stress on the ignition module and risk
for short-circuiting.
Check if a spark occurs when attempting to
start.
Test with test spark plug no. 502 71 13-01 if
no spark is seen.
Also check that the stop switch is in the
start position.
Earth the spark plug on the cylinder and
pull sharply on the start handle.
A spark should be seen between the
electrodes.
If no spark is seen test with test spark plug
no. 502 71 13-01.
If a spark then occurs, the spark plug is
faulty.
Try a new spark plug.

2
9
502 50 06-01
Electrical system
When there is still no ignition spark,
dismantle the short-circuit cable from the
stop switch.
Remove the connector by prying it up out
of the throttle with a knife.
If the plug now sparks, the fault is either in
the stop switch or the short-circuit cable.
Still no spark?
Check the ignition cable’s connection to
the spark plug cover.
Still no spark?
Check the spark plug connection.
Remove the spark plug cover and make
sure the ignition cable is not damaged.
Remove a segment of cable if required
to get sufficient contact at the connection
coil.
Use pliers no. 502 50 06-01 to make a
hole in the ignition lead.
When a part of the ignition lead has been
cut off it helps to use the pliers no.
502 50 06-01 to make a hole in the igni-
tion lead to fit the contact coil.
NOTE!
It is important that the tip of the
contact coil hits the centre of the
ignition lead to prevent sparking.
Attach the ignition coil to the ignition
cable.
Attach the ignition coil to the ignition cable
and ensure that the wire is folded along
the cable.
Slide the contact coil into the spark plug
cover.
TIP!
Lubricate the hole in the spark plug cover
so that it is easier to slide in the contact
coil.
NOTE!
The stop switch and the ignition
module are adapted to each other.
If the switch is damaged, it shall be
replaced with one of the same type.

2
10
502 51 34-02
Electrical system
Still no spark?
Check the air gap.
See ”Dismantling” below.
Still no spark?
Check the air gap between the flywheel
magnet and the ignition module. The gap
should be 0.3 mm.
Use a 502 51 34-02 feeler gauge.
See ”Dismantling” below.
Still no spark?
Check other cables and connections.
Still no spark?
Check other cables and connections for
poor contacts (dirt, corrosion, cable brea-
kage and damaged insulation).
Make sure that the cables are correctly
drawn and lie in the cable grooves.
Do not forget to check the cables in the
throttle too.
See chapter 3 “Throttle”.
TIP!
Use an Ohmmeter in order to easily check
if cable breakage has occurred, due to
pinching, for example.
Adjust the air gap. Adjust the air gap as needed to the cor-
rect value.
• Loosen the bolts.
• Position the feeler gauge and press
the ignition module against the fly-
wheel.
• Tighten the bolts and check the air gap
again.
If the spark plug still does not fire, the
ignition system should be replaced.
Dismantling
Dismantle the air filter cowling, spark
plug, starter, cylinder cover and the guard
over the muffler.
Unhook the throttle cable from the carbu-
rettor.
Dismantling
The following components must be
dismantled for the ignition system to be
accessible.
The air filter cowling, spark plug, starter,
cylinder cover and the guard over the
muffler.
Unhook the throttle cable from the carbu-
rettor.
NOTE!
Do not lose the rubber bushings fitted between the starter and the fuel tank.

2
11
502 50 18-01
502 51 49-01
E
E
E
F
G
Electrical system
Dismantle the short-circuit cable from the
ignition module.
Dismantle the short-circuit cable from the
ignition module by removing the screw (F)
and prying off the flat pin connector (G).
Dismantle the guard plate under the en-
gine body (2 remaining screws).
Lift out the ignition lead and short-circuit
cables from their guides.
Remove the 3 screws (E) and swing the
engine body to one side so the clutch
becomes accessible.
Remove the nut holding the flywheel. Remove the nut holding the flywheel.
Fit the puller on the flywheel. Loosen and
remove the nut.
Dismantle the ignition module and the
centrifugal clutch.
Remove the remaining screws (A) holding
the ignition module and both screws (B)
that hold the centrifugal clutch.
Lift off the clutch, both support washers
and the ignition module.

2
12
502 51 49-01
502 51 34-02
Electrical system
Remove the flywheel. Dismantle the flywheel from the crankcase
using the puller
no. 502 51 49-01.
Gently knock the puller screw with a
hammer, if the flywheel sits tightly on the
crankshaft.
Assembly
Check that the cast key in the flywheel
and key way in the crankshaft are unda-
maged.
Fit the flywheel and centrifugal clutch. Do
not forget the washers (A).
Note the slots on the washer lie closest to
the flywheel. Align with the equivalent pins
on the flywheel.
Assemble the ignition module (part
number 501 31 98-01) and adjust the air
gap to 0.3 mm.
Assemble the ignition module (part
number 501 31 98-01).
Adjust the air gap. It should be 0.3 mm
between the permanent magnets in the
flywheel and the ignition module.
Tighten the screws and do not forget the
ring cable lug under the outer screw.
Assemble other parts in the reverse order
as set out for dismantling.
NOTE!
Do not forget the rubber bushings between the fuel tank and the crankcase/
clutch cover and the fuel tank and starter.
NOTE!
The completely flat side on the
clutch should rest against the
washer closest to the flywheel.
NOTE!
The stop switch and the ignition
module are adapted to each other.
An older version of an ignition
module may not be fitted, as the stop
switch function is then altered.
If the ignition module needs to be
replaced, the new one shall have
part number 501 31 98-01.

3
13
3
Fuel system
Fuel system
Contents
Air filter __________________________________14
Tank venting ______________________________15
Fuel filter _________________________________15
Fuel pump ________________________________16
Carburettor _______________________________16
Throttle handle model RJ ___________________ 23
Throttle handle model R ____________________ 24
Start throttle speed ________________________ 25
Carburettor settings________________________ 25

3
14
505 69 85-70
531 00 60-76
Fuel system
In addition to the fuel tank and carburettor, the fuel system consists of the air filter, fuel filter and
tank venting.
All these components interact so that the engine receives the optimal mixture of fuel and air to
make it as efficient as possible. Very small deviations in the carburettor setting or a blocked air
filter have a large effect on the running and efficiency of the engine.
The carburettor can come from several different manufacturers on our models, but the function
and repair methods are essentially the same.
NOTE!
Make sure that the air filter is free of cleaning agent before it is impregnated
with air filter oil.
Air filter
Dismantle the air filter cowling. Remove
the air filter and clean it in warm soapy
water.
A damaged filter should be replaced with
a new filter.
Air filter
Dismantle the air filter cowling by loose-
ning the quick clasps and lift off the air
filter.
The filter is manufactured of foamed
plastic and should be cleaned in tepid
soapy water.
A damaged filter should be replaced with
a new filter.
WARNING!
Do not clean not the filter with petrol. Hazardous!
TIP!
Use Husqvarna’s cleaning agent Active
Cleaning no. 505 69 85-70.
Impregnate the filter with air filter oil. Impregnate the filter with air filter oil.
TIP!
Place the filter in a plastic bag and pour
about a tablespoon of air filter oil no.
531 00 60-76 into the bag.
Massage the oil into the air filter.

3
15
502 50 83-01
531 03 06-23
Fuel system
Tank venting
Tank venting takes place through the fuel
cap and needs to be functional for the
engine to work.
• Remove the starter.
• Remove the air filter cover and
dismantle the cylinder cover.
• Remove the fuel hose from the
carburettor, remove the fuel tank and
empty the tank of fuel.
• Connect the fuel hose to pressure
tester part number 531 03 06-23 and
plug the return line shut.
• Make sure that the hose bushings in
the tank are leak tight.
• Pump up a pressure and vacuum of 50
kPa (0.5 bar) in the tank.
• The pressure should drop to 20 kPa
(0.2 bar) or revert to atmospheric
pressure within 45 seconds.
The fuel cap can be taken apart for clea-
ning.
Use a screwdriver and press off the hou-
sing (A) that contains a rubber diaphragm
(B) and a filter (C) and cover (D).
Blow the filter (C) clean, and the sintered
filter (E), with compressed air and mount
the fuel cap in the reverse order to how it
was disassembled.
Make sure that the flat surface on the co-
ver (D) is turned towards the diaphragm.
NOTE!
There is a small slit (F) in the
diaphragm (B) that becomes visible
when you carefully pull the edges
of the diaphragm. Check that the
edges of the slit are not damaged.
Replace diaphragm if necessary.
Tank venting
Check that the tank venting valve works
correctly.
Fuel filter
The fuel filter can be removed through the
tank’s fill hole.
Fuel filter
The fuel hose in the tank contains a fuel
filter. It is accessible through the fill hole.
Pull out the filter with your fingers or with
help of tool 502 50 83-01.
Clean the filter externally if it is not too
dirty.
Replace the filter if required.
If the filter is not too dirty, its surface can
be cleaned with a brush.
Otherwise it must be replaced.
Check the fuel hose for cracks and leaks.
Make sure that the filter’s connection neck
is inserted as far as possible into the fuel
hose and that the O-ring is sufficiently
tight so that the filter cannot slide off the
tube.

3
16
505 38 13-08 502 50 18-01
Fuel system
Fuel pump
The fuel pump facilitates cold starts.
Fuel pump
The fuel pump has the task of facilitating
the start of the engine when cold. The
pump fills the carburettor with fuel before
attempting to start the engine. This also
prevents vapour bubbles from blocking the
narrow fuel channels.
If the pump does not work it must be
replaced.
Dismantle the cylinder cover and starter,
and move the fuel tank to the side.
Note how the fuel hoses are connected to
facilitate assembly.
Pull the fuel hoses off the pump and
dismantle it by pressing on the resilient
plastic tongue (A).
Assemble in reverse order.
NOTE!
The return hose to the fuel
tank shall be fitted on the long
connection to the fuel pump.
Carburettor
Dismantling
Blow the carburettor compartment clean
and remove the nuts and the screw which
hold the carburettor and air filter housing.
Carburettor
Dismantling
1. Remove the air filter cover and
cylinder cover and blow the carburettor
compartment clean with compressed
air.
2. Remove the nuts and screw which
hold the carburettor and air filter
housing.
NOTE!
Do not lose the washer under the
head of the upper screw.
Unhook the throttle cable.
Fold the air filter holder to the side.
Remove the hose between the carburettor
and fuel pump.
Pull off the carburettor.
3. Unhook the throttle cable (3) from the
carburettor.
4. Press off the fuel hose (black) (4) from
the carburettor.
5. Pull the hose between the fuel pump
and tank up as far as necessary to fold
the air filter holder to the side.
6. Remove the hose between the
carburettor and fuel pump.
7. Pull the carburettor off from the
cylinder.
NOTE!
Note how the different fuel hoses are
fitted.

3
17
Fuel system
The carburettor’s design
The carburettor can be divided into three
different functional units: the metering unit,
the blending unit, and the pump unit.
The metering unit
The needles and the fuel control functions
are located here.
The carburettor’s design
The carburettor can be divided into three
different functional units: the metering
unit, the blending unit, and the pump unit.
The metering unit
The needles (A) and the fuel control func-
tions are located here.
The needle valve (B) and control
diaphragm (C) are vital to the
carburettor’s function.
The blending unit
Fuel and air are mixed here.
The blending unit
In this section of the carburettor fuel and
air are mixed in the proper proportions.
The choke and throttle valves are placed
here.
In the middle of the venturi (narrowest
part of the throughput) the main jet (D) is
found.
The pump unit
Pumps fuel from the tank to the carburet-
tor.
The pump unit
This is where the pump diaphragm (E)
that pumps fuel from the tank to the
carburettor’s measuring unit is found.
The diaphragm is affected by pressure
variations in the engine’s crankcase via an
impulse channel (F).
If the channel is blocked, by grease or
a wrongly facing gasket, for example,
the pump unit does not function and the
engine cannot be started.

3
18
531 03 06-23
Fuel system
Dismantling the carburettor
Remove the control diaphragm and check
for damage.
Replace if required.
Dismantling the carburettor
Carefully remove the control diaphragm
(A) and gasket (B).
Check the diaphragm for holes and wear
on the pin (C).
Replace the diaphragm if required.
Pressure test the metering unit. Connect pressure tester 531 03 06-23 to
the fuel hose nipple.
Lower the carburettor in a vessel with
petrol in order to discover any leaks more
easily.
Test the pressure at 50 kPa.
No leakage is permitted.
In the event of leakage – remove the
needle valve.
In the event of leakage – remove the
needle valve.
Loosen the bolt and remove the lever arm,
axle, needle valve and spring.

3
19
540 06 82-01
Fuel system
Pull the locking plugs (A) off over the jet
needle with the aid of the special tool
540 06 82-01 (left-hand threads).
The plugs cannot be dismantled if the slot
in the plug is centred above the ball (B) in
the carburettor housing.
Unscrew the jet needles.
NOTE!
Note how the jets are positioned.
(For example, the H-needle is a little
shorter than the L-needle).
Check the needle valve and the lever arm
for damage or wear.
Replace damaged components with new
ones.
Check the needle valve for damage on the
tip and in the lever arm groove.
Check the lever arm for damage to the
groove for the needle valve and wear on
the mounting points towards the control
diaphragm.
Replace damaged components with new
ones.
Remove the pump diaphragm.
Check the diaphragm for damage.
Remove the fuel screen and clean it or
attach a new one.
Remove the bolt holding the cover over
the pump diaphragm.
Lift off the cover (A), the gasket (B) and
the diaphragm (C).
Check the diaphragm for damage to the
valve tongues. If the valve tongues are
bent, the pump will not function in a satis-
factory manner.
Hold it up to a light as well to discover any
holes in the material.
Carefully remove the fuel screen (D),
using a needle for example. Clean or
replace the fuel screen.
NOTE!
During assembly the pump
diaphragm should lie closest
to the carburettor housing.