Dolmar PS-350 User Manual

Repair Manual

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PS-350
PS-420

Caution:

Before doing any maintenance or service work, the combination switch must be engaged in the service position, in

order to prevent unintended starting by the easy start system!

Reparaturanleitung PS-4600 / PS-5000 1

Repair manual PS-350 / PS-420

www.dolmar.de

CONTENTS

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Page

Technical data ........................................................................................................................................................................... 3

Troubleshooting ........................................................................................................................................................................ 4

00 Special tools..........................................................................................................................................................................5 - 7

01 Sprocket guard / Chain tensioning system ................................................................................................................................ 8

02 Clutch drum with chain sprocket ............................................................................................................................................... 9

03 Chain brake / Guide bar bolt ............................................................................................................................................ 10 - 11

04 Clutch................................................................................................................................................................................12 - 13

05 Oil pump................................................................................................................................................................................... 14

06 Starter ...................................................................................................................................................................................... 15

07 Ignition system (trouble-shooting)............................................................................................................................................ 16

07 Ignition system................................................................................................................................................................. 17 – 18

08 Carburetor........................................................................................................................................................................ 19 – 20

09 Vibration damper...................................................................................................................................................................... 21

10 Tank................................................................................................................................................................................. 22 – 23

11 Cylinder / Piston .............................................................................................................................................................. 24 – 26

12 Crankcase / Crankshaft ........................................................................................................................................................... 27

13 Torques ................................................................................................................................................................................... 28

Reparaturanleitung PS-4600 / PS-5000 2

Repair manual PS-350 / PS-420

TECHNICAL DATA

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Stroke volume cm3 34.7 42.4
Bore mm 38 42
Stroke mm 30.6 30.6
Max. power at speed kW / 1/min 1.5 / 9,500 2.0 / 9,500
Max. torque at speed Nm / 1/min 1.9 / 6,500 2.4 / 6,500
Idling speed / max. engine speed with bar and chain 1/min 2,800 / 13,500 2,800 / 13,500
Clutch engagement speed 1/min 5,100 5,100
Sound pressure level at the workplace L
Sound power level L
Vibration acceleration a

- Tubular handle m/s2

- Rear handle m/s2 3.6 3.2

Carburetor (diaphragm, choke flap carburetor) Typ membrane carburetor membrane carburetor
Ignition system Typ electronic electronic
Spark plug Typ NGK BPMR 7A NGK BPMR 7A
Electrode gap mm 0.5 0.5
or spark plug Typ BOSCH WSR 6F, CHAMPION RCJ 6Y BOSCH WSR 6F, CHAMPION RCJ 6Y
Fuel consumption at max. load per ISO 7293 kg/h 0.79 0.96
Specific consumption at max. load per ISO 7293 g/kWh 526 480
Fuel tank capacity l 0.48 0.48
Chain oil tank capacity l 0.28 0.28
Mixture ratio (fuel/two-stroke oil)

- when using DOLMAR oil

- when using Aspen Alkalyt (two-stroke fuel) 50 : 1 (2%) 50 : 1 (2%)

- when using other oils 40 : 1 (quality grade JASO FC or ISO EGD) 40 : 1 (Qualitätsstufe JASO FC oder ISO EGD)

Chain brake engages manually or in case of kickback engages manually or in case of kickback
Chain speed at max. power m/s 18.1 18.3
Sprocket pitch inch 3/8 .325
Number of teeth Z 6 7
Chain type see the spare-parts list see the spare-parts list
Pitch / gauge inch 3/8 / 0.050 (1.3) .325 / 0.050 (1.3)
Guide bar, length of a cut cm 30, 35, 40 33, 38, 45
Guide-bar type see the spare-parts list see the spare-parts list
Weight (fuel tank empty, without chain, guide bar and accessories) kg 4.7 / 4.8 2) 4.7 / 4.8 2)

1)

Figures derived in equal part from idling, full-load and racing speed.

2)

On models with catalytic converter.

per ISO/CD 22868 1) dB (A) 110 110

WA av

per ISO 22867 1)

h,w eq

per ISO/CD 22868 1) dB (A) 100.8 100.8

pA av

PS-350 PS-420

4.3

50 : 1 / 100: 1 (HP-100)

3.6

50 : 1 / 100: 1 (HP-100)

Reparaturanleitung PS-4600 / PS-5000 3

Repair manual PS-350 / PS-420

TROUBLESHOOTING

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Malfunction System Observation Cause

Chain does not run Chain brake Engine runs Chain brake actuated, Chain too tight

Engine does not start
or

only with difficulty

Fuel supply

Engine speed gets
“stuck”

Ignition system

Compression

Mechanical malfunction

Multiple systems Engine speed about

Ignition spark

No ignition spark

Fuel tank is filled

Inside system

Outside
Starter does not engage

4,500 - 6,000 rpm

Malfunction in fuel supply system, pressure system,
mechanical malfunction.
STOP switch stuck in service position, fault or short-

circuit in the wiring,
plug cap or spark plug defective,
gap between ignition module and flywheel uneven or too

wide
Combination switch in Choke position,

carburetor defective, suction head dirty,
fuel line bent, leaky or interrupted.
Cylinder base packing ring defective, radial shaft

packings defective,
cylinder or piston rings defective
Spark plug does not seal.
Spring in starter broken, broken parts inside the engine.
Carburetor too lean
Bleed air at cylinder and/or rubber induction piece
Fuel line bent, throttle link stuck

Warm engine won’t
start

Engine starts, but
dies immediately

Insufficient power

No chain lubrication

Reparaturanleitung PS-4600 / PS-5000 4

Repair manual PS-350 / PS-420

Carburetor Fuel tank is filled

Ignition spark

Fuel supply Fuel tank is filled Wrong idling adjustment, suction head or carburetor dirty,

Several systems
may be involved
simultaneously

Oil tank/pump

Engine is idling

No oil on the chain

Wrong carburetor adjustment
Flooded from choke use
Piston ring worn (max. thrust play 0.5 mm)

tank venting defective, fuel line interrupted, cable
defective, Choke flap closed, decompression valve dirty

Air filter dirty, incorrect carburetor setting, muffler
clogged, exhaust channel in cylinder clogged, spark
arrester screen clogged.

Oil tank empty
Oil guide groove dirty, Oil suction head dirty
Oil pump adjusting screw incorrectly adjusted
Oil pump worm drive gear defective

1

2

3

4

5

00 SPECIAL TOOLS

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1 Torx screwdriver

Grip (944.500.860)
T-grip 200 mm (944.500.862)
T-grip 100 mm (944.500.861)

2 Mandrel

Disassembly mandrel for

tapping out the flywheel
without damage to
the crankshaft thread (944.500.880)

3 Setting gauge

Gauge for measuring the gap

between flywheel and
armature (944.500.891)

4 Torque wrench

3/8” Drive socket (944.500.864)
Bit 152 mm (944.500.865)
Bit 49 mm (944.500.866)
Torque wrench

3/8” Drive (950.230.000)

5 Piston stop wedge

Wedge for blocking

Reparaturanleitung PS-4600 / PS-5000 5

Repair manual PS-350 / PS-420

the engine through the
exhaust port (944.602.001)

6 7

9

8

10

11 12 13

00 SPECIAL TOOLS

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6 Piston ring tensioner

Piston ring band and

assembly tool for cylinders (944.600.001)

7 Assembly and disassembly wrench

Wrench for disassembling and

assembling the centrifugal
clutch (944.500.590)

8 Pressure gauge

Pressure guage for checking

the carburetor fuel valve (956.004.000)

Electronic tachometer for measuring

the engine speed of
2- and 4-stroke engines (950.233.220)

10 3/8” socket

9 Tachometer

Installation/removal of
Spark plug, clutch (944.500.864)

11 Needle-nose pliers

Various assembly/
disassembly tasks (944.603.400)

12 Disassembly hook

Removal/installation
Brake band spring (950.237.000)

13 Over/underpressure pump

For checking sealing of
radial rings and gaskets (957.004.001)

Reparaturanleitung PS-4600 / PS-5000 6

Repair manual PS-350 / PS-420

14 15

00 SPECIAL TOOLS

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14 Sealing plate

For sealing intake side (944.603.020)

15 Sealing plate

For sealing exhaust side (944.603.170)

Reparaturanleitung PS-4600 / PS-5000 7

Repair manual PS-350 / PS-420

1

01 SPROCKET GUARD / CHA

IN TENSIONING SYSTEM

An angled worm drive converts the turns of

clockwise,

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Remove the sprocket guard, bar, and chain.

CAUTION: Do not work on the chain brake
unless the spring is detensioned!

If necessary, turn adjusting screw 1
until the fastening screw is accessible.
Unscrew the fastening screw and pull the
chain tensioner up and out.

Assembly

Grease spindle and worm gear with multi­purpose grease (944.360.000).

Chain tensioner
Carefully take the chain guide cover off the

guide bar bolts.
Unscrew 4 screws, and remove the spike bar

and the cover.

Chain tensioner function

the adjustment screw 1 to forward or
backward motion of the tensioning pin.

Reparaturanleitung PS-4600 / PS-5000 8

Repair manual PS-350 / PS-420

4

3

2

1

02 CLUTCH DRUM AND CHAIN SPROCKET

wrench.

as far as necessary so the clutch drum can be

Clutch drum with sprocket and needle

wear.

worn chain sprocket will damage a new saw

wear and damage.

Assembly the bearing with

When

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Remove the sprocket guard, bar, and chain.
Remove the circlip 4 with the universal

Remove cup washer 3.
Pull the handguard towards the front grip only

removed.

bearing
Check the chain sprocket 2 for damage and

Important customer information:

Before installing a new saw chain, always
check the condition of the chain sprocket. A

chain, and must be replaced.
Check the clutch drum needle bearing for

multi-purpose high-

performance grease (944.360.000).
Check the inside of the clutch drum for

damage and wear.
Replace the clutch drum if damaged or worn.

Note: Always use a new circlip 4
(927.408.000)!

When assembling the clutch drum, make
sure that the lug of the oil pump drive 1 is
not positioned on the oil pump drive.
inserting, turn the clutch drum slightly.

Reparaturanleitung PS-4600 / PS-5000 9

Repair manual PS-350 / PS-420

1

2

3

03 CHAIN BR

AKE / GUIDE BAR BOLT

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Removing the brake band
CAUTION: Wear protective gloves to

prevent cuts!

Remove the sprocket guard, bar, and chain.
Remove the clutch drum, see Chapter 02.
Push the hand guard forward to engage the

chain brake. This tensions the brake band
spring.

Remove the cover plate, see Chapter 01.
Fold the brake band 1 upward and turn it out

of the disengagement mechanism 2.

Secure the chain saw from slipping (vise).
Using the disassembly hook (Chap. 00, Pos.

12), disengage the brake band spring 3.

Reparaturanleitung PS-4600 / PS-5000 10

Repair manual PS-350 / PS-420