Husqvarna 42, 242XP, 246 Instruction manual

42, 42D, 242
Workshop Manual
531 03 01-21
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Introduction
The procedures included in this workshop
manual are designed to provide you, the tech-
nician, with the necessary information for repair
and service of models 42, 42D and 242 chain
saws.
The information, specifications and illustrations
in this publication are based on the information
in effect at time of printing. Continued product
improvement may result in changes to these
saws that may not be included in this manual.
Later editions are revised to include any prod-
uct changes that may have occurred.
Safety Statements
The following safety statements are found
throughout this manual and are designed to
make you aware of potential hazards or unsafe
practices.
- WARNING -
Immediate hazards which can
result in severe injury or death.
CAUTION: Hazards or unsafe practices
which can result in severe personal injury.
IMPORTANT: Hazards or unsafe practices
which can result in product or property
damage.
NOTE: Additional pertinent information.
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Table of Contents
= Page No.
Section
© Husqvarna Forest& Garden 1995
1
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Technical Specifications
Engine
Displacement -----------------------------------------------------------
Bore -----------------------------------------------------------------------
Stroke ---------------------------------------------------------------------
Maximum No Load RPM
Model 242 -----------------------------------------------------------
Model 42(D) ---------------------------------------------------------
Idling Speed -------------------------------------------------------------
Clutch Engagement Speed ------------------------------------------
Fuel and Chain Lubrication System
Carburetor ---------------------------------------------------------------
Fuel Tank Volume ------------------------------------------------------
Oil Pump Capacity -----------------------------------------------------
Oil Tank Volume --------------------------------------------------------
Ignition System
Ignition System ---------------------------------------------------------
Air Gap -------------------------------------------------------------------
Spark Plug ---------------------------------------------------------------
Electrode Gap -----------------------------------------------------------
Heated Handles
Model 242 ----------------------------------------------------------------
Model
42(D) -------------------------------------------------------------
Bar and Chain
Bar Length Minto Max -----------------------------------------------
Drive Sprocket ----------------------------------------------------------
Chain Speed
Model 242 -----------------------------------------------------------
Model 42(D) ---------------------------------------------------------
Chain Pitch --------------------------------------------------------------
Drive Link Gauge ------------------------------------------------------
Weight
Model 242 ----------------------------------------------------------------
Model
42(D) -------------------------------------------------------------
Weight with 13 inch Guide Bar and Chain
Model 242 ----------------------------------------------------------------
Model 42(D) -------------------------------------------------------------
42.0 cc (2.5 cu. in.)
42.0 mm
30.0 mm
15500rpm
13000 rpm
2900 rpm
3900 rpm
Walbro HDA 34
0.5 Iitres (1.1 pints)
3-7 cc/rein at 9000 rpm
0.27 Iitres (0.55 pints)
SEM AM7
0.3 mm (.012 inch)
NGK-BPMR6A
CHAMPION-RCJ7Y
0.5 mm (.02 inch)
65 watts at 10000 rpm
NA
13-18 inches (33 -46 cm)
7 tooth
19.7 m/secat9000 rpm
17.3 m/secat9000 rpm
0.325 inches
1.5 mm (.058 inches)
4.6 kg (10.1 Ibs)
4.5 kg (9.9 Ibs)
5.3 kg (1 1.7 Ibs)
5.2 kg (1 1.4 Ibs)
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Service Tools
2
5025006-01
5025026-01
5025030-07
5025033-01
5025038-01
5025067-01
5025070-01
5025079-01
5025082-01
5025083-01
5053818-17
5025134-02
5025149-01
5025161.01
50271 13-01
5027114-01
Assembling pliers, spark plug
Puller screw
Crankshaft installer
Piston stop
Pressure gauge
Wrench (11 mm)
Piston ring compressor
Seal Installer
Drift
Hook for fuel filter
Oil gear puller
Air gap gauge
Holding bar for flywheel puller
Crankcase puller
Test plug
Tachometer
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3
Safety Equipment
Chain Brake
Disassembly
Disengage chain brake. Remove clutch cover
retaining nut and remove cover. Clean chain
brake and clutch cover assembly,
Remove hand guard retaining screw. Rethread
screw into pivot sleeve two turns. Press on
screw head to drive out inner pivot sleeve half.
Turn cover to opposite side. Using a suitable
punch, remove outer half of pivot sleeve.
Separate hand guard from cover.
4
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Safety Equipment
3
Remove screws (4) and cover plate.
– WARNING -
Wear eye protection when
removing spring to prevent
injury
Using a screwdriver, pry out brake spring.
Using a punch, drive out knee link retaining
pin.
5
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3 Safety Equipment
Position punch in clutch cover as shown, and
drive out brake band roll pin. Remove brake
band and knee link assembly.
Check brake band for damage or wear. The
brake band thickness should not be less than
0.75 mm (.030”) when measured at any point
along the band.
The brake band must be replaced if the band is
damaged or worn less than minimum thick-
ness. If brake band requires replacement,
remove screw and replace band.
6
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Safety Equipment
3
Apply a thin coating of oil to brake mechanism
parts. Position brake band and knee link in
cover.
Install knee link assembly and roll pins. Install
spring on knee link mechanism.
- WARNING -
Wear eye protection when
installing spring to prevent
injury
With screwdriver positioned as shown, press
spring into place.
I
7
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3
Safety Equipment
Install cover plate and secure with (4) screws.
Position hand guard on clutch cover. Press
pivot sleeve halves into place.
Install and tighten screw. Disengage chain
8
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Safety Equipment
3
Install bar, chain and clutch cover on saw. Test
chain brake for proper operation.
Inertia Chain Brake Engagement
Hold the saw approximately 35 cm (14”) above
a stump or other firm object. Release grip on
front handle and allow front of saw to drop.
When the bar tip hits the object, the chain
brake should activate.
Manual Chain Brake Engagement
Place the saw on firm ground and start the
engine. While holding the saw with both hands,
apply full throttle. Activate chain brake by turn-
ing left wrist against hand guard as shown.
Chain should stop immediately.
- WARNING -
Avoid contact between any
object and the guide bar tip.
Contact can cause the chain and guide bar to
suddenly move upward and backward toward
the user. Use both hands on the handles.
Follow all safety precautions in the operator’s
manual. Failure to follow instructions could
result in serious personal injury.
9
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3
Safety Equipment
Throttle Trigger Lockout
Disassembly
Press out pin and remove throttle lockout.
Assembly
Install throttle lockout and secure with pin.
Chain Catcher
Inspect chain catcher. If damage is evident,
remove screw and replace chain catcher.
10
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Starter 4
Disassembly
Remove screws (4) and starter assembly.
Pull starter cord out
approximately 30 cm (1 2“)
and position in starter pulley recess. Carefully
allow pulley to rotate counterclockwise until
spring tension has been relieved.
Remove screws (4) from guard ring.
1
I
I
11
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Starter
- WARNING -
Wear eye protection when
removing spring to prevent
injury
Remove center post screw and washer.
Carefully withdraw starter pulley.
- WARNING –
Wear eye protection when
removing spring to prevent
injury
Position starter so spring side is toward bench.
Tap housing down on bench sharply to remove
recoil spring.
Clean all starter parts and check for wear or
damage.
12
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Starter 4
Assembly
- WARNING -
Wear eye protection when
installing spring to prevent
injury
Insert hook on outer end of recoil spring into
starter housing as shown. Using thumbs, care-
fully install new recoil spring into place.
Install starter cord into pulley as shown. Melt
cord end to seal knot. If knot is too large it may
interfere with starter pawls.
Thread starter cord through retaining rinq and
eyelet as shown. Attach starter handle to rope.
13
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4 Starter
Apply a light coating of oil to starter pulley post
and recoil spring.
Position starter pulley on starter housing as
shown. Rotate pulley to engage recoil spring in
pulley.
IMPORTANT: Starter pulley must be flush
against recoil spring.
Secure starter pulley with washer and screw.
Install guard ring with screws. Pull starter han-
dle out and stop starter pulley with thumb. Lift
cord into pulley recess, then preload spring by
turning pulley three turns clockwise.
14
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Starter 4
Pull starter cord all the way out. Make sure
(
starter pulley can be turned at least 1/2 turn,
before the recoil spring fully tightens.
With starter handle extended approximately 30
cm (1 2“) from housing, position starter against
saw. Release starter handle to allow the pulley
to fit within the starter pawls on flywheel.
Secure starter with screws.
?
15
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5
Ignition System
Description
Models 42, 42D and 242 are equipped with an
electronic ignition system. The spark generated
by this system has a higher energy and a
shorter burning time than the spark generated
by a breaker point ignition. Because of this, the
spark, across the spark plug electrode,
appears to be weaker.
0.5mm (.020”)
Checking the Spark
Remove and clean spark plug. Check spark
plug electrode gap.
Spark plug gap should be 0.5 mm (.020”). If
electrodes are worn, spark plug must be
replaced.
With ON/OFF switch in “ON” position, ground
spark plug to cylinder and pull starter handle. A
spark should appear across the electrodes.
16
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IgnitionSvstem
5
If no spark appears, install new spark plug or
test plug P/N 50271 13-01 and pull starter
handle.
If no spark appears, remove ON/OFF switch
lead from stop switch and pull starter handle,
spark appears, stop switch is faulty and musl
be replaced. If no spark appears, check high
tension leads, connections and contacts for
dirt, wear and/or damage.
If
Using air gap gauge P/N 5025134-02 check
air gap between flywheel magnet and ignition
module. Air gap should be 0.3 mm (.012”).
17
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5
Ignition System
18
If replacing ignition module does not restore
spark, replace coil.
Replacement of the Ignition Module
Remove leads from ignition module. Remove
screws and ignition module. Position new igni-
tion module as shown and install but do not
tighten screws.
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