Page 1
Repair Manual
___
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
Page 2
CONTENTS
___
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
Page 3
TECHNICAL DATA
___
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
Page 4
TROUBLESHOOTING
___
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
Page 5
1
2
3
4
5
00 SPECIAL TOOLS
___
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)
Page 6
6 7
9
8
10
11 12 13
00 SPECIAL TOOLS
___
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
Page 7
14 15
00 SPECIAL TOOLS
___
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
Page 8
1
01 SPROCKET GUARD / CHA
IN TENSIONING SYSTEM
An angled worm drive converts the turns of
clockwise,
___
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
Page 9
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
___
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
Page 10
1
2
3
03 CHAIN BR
AKE / GUIDE BAR BOLT
___
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
Page 11
Assembly: Apply Loctite 243 (980.009.000) to
4
56
7
03 CHAIN BR
AKE / GUIDE BAR BOLT
Assemble the handguard and disengagement
___
Remove the handguard and
disengagement mechanism
Unscrew bolt 4 and pull out the sleeve 5.
Push handguard arm 6 from its position over
the hood towards the muffler.
Remove the circlip 7.
Pull the disengagement mechanism up in
parallel with the axes.
Pull off the handguard with gentle back-and-
forth motion.
When reassembling always use a new
circlip 7 (927.304.000)!
mechanism, brake band and brake band
spring in reverse order.
Replacing the guide bar bolt
Screw two nuts onto the bar bolt and
counterlock them.
Unscrew the bar bolt.
the guide bar bolts and turn them all the way
in.
Reparaturanleitung PS-4600 / PS-5000 11
Repair manual PS-350 / PS-420
Page 12
12
3
4 5
04 CLUTCH
CAUTION: To prevent cuts, wear protective
ndguard towards the front handle to
Remove the muffler. To do this, unscrew the 3
___
Disassembly
gloves!
Remove the sprocket guard, bar and chain.
Pull the ha
release the chain brake if necessary.
Remove the clutch drum, see Chapter 02.
screws 1 and remove the upper muffler half 2.
Caution: If a catalytic converter is being
used, the muffler will be very hot after
operation!
Move piston to bottom dead centre (visible
through the exhaust opening).
Press the piston stop wedge 3 (cap. 00, pos.
5) into the exhaust opening.
Note: Before the piston stop wedge is
pressed into the exhaust opening, it is
necessary to remove the carbon insert in the
exhaust.
Insert wrench 4 (Chap. 00, Pos. 7) into the
clutch and use a socket wrench 5 to turn in
the direction of the arrow (left-hand thread) to
loosen and remove the clutch.
Turn the clutch over and remove the disc.
The flyweights can now be pushed off the
guide axially in one direction.
Reparaturanleitung PS-4600 / PS-5000 12
Repair manual PS-350 / PS-420
Page 13
04 CLUTCH
The press the flyweights onto the guide. To do
way, then
CAUTION: Note the position of the springs.
___
Inserting the flyweights
Hook the springs as shown in the illustration.
this, first push on two flyweights halfput on the third flyweight by setting it on its
edge.
Press the flyweights all the way onto the
guide.
Do not replace springs individually! If a
spring breaks or is fatigued, all three
springs must be replaced. The springs
must not touch the cover.
The illustration shows the inside of the clutch.
Press the disc onto the clutch. It must be flat
and be engaged.
Installing the clutch
Install the clutch with the arrow marking point
up.
CAUTION
disassemble the starter in order to prevent
damage to the starting ratchets
: Before installing the clutch,
Reparaturanleitung PS-4600 / PS-5000 13
Repair manual PS-350 / PS-420
Page 14
1 2
3
4
A
1
2
5
3
4
6
8
7
9
05 OIL PUMP
The oil pump is driven by the clutch drum. Lugs
___
General
on the clutch drum transfer the power to the
drive arms of the oil pump drive 1.
The drive worm of the oil pump drive engages
in the teeth of the oil pump 3.
This means that oil is pumped only when the
chain is running.
The oil flow rate can be adjusted with adjusting
screw A:
• Turn right for more oil
• Turn left for less oil
Disassembly
Remove the clutch drum and clutch, see
chapter 04. Remove brake band, see chapter 03.
Turn the oil pump drive 1 counter-clockwise
and pull it off the shaft.
Pull the oil pressure line 2 from the oil pump.
Unsrew 2 screws 4 and remove the oil pump.
Reparaturanleitung PS-4600 / PS-5000 14
Repair manual PS-350 / PS-420
The suction line 4 remains in the crankcase. It
extends into the oil tank. To remove it, carefully
pull on the connection to the oil pump.
Removing the oil pump
Pull the plastic housing off the oil pump by
carefully spreading it apart in the area of the
holes marked 5 in the illustration.
Push the adjusting screw 6 up against the
spring pressure and turn it until the pin 7 goes
into the assembly slit 7. If necessary press the
supply piston 8 in somewhat.
Note: For assembly put the adjusting screw in
stop positions 2 or 3, not in one of the outer
stops.
Removing the oil tank vent
Note: The ventilation valve must be pulled out.
It cannot be knocked into the tank.
Page 15
If the spring pops out, put it back into the plastic
1
2
4
5
6
7
8
9
3
06 STARTER
___
Disassembly
Unscrew four screws 1.
Remove fan housing 2.
Remove air guide 3 from fan housing.
Detension the return spring.
Injury hazard! Unscrew screw 5 only after
detensioning the return spring!
Unscrew screw 5 and remove actuator 6 and
spring 7.
Pull off the cable drum 8.
Knock the fan housing against a tabletop with
the entire contact surface of the hollow side,
so that the return spring cassette 9 pops out
of the fan housing.
Caution! The return spring can jump out of
the plastic cassette! Always wear
protective goggles and gloves!
housing as shown in the schematic.
Assembly
Note: If installing a new return spring cassette,
grease it on the spring side.
Carefully insert new return spring cassette 9
and push it in. Lightly grease the surface of the
spring and spring cassette with multipurpose
grease (944.360.000).
Thread in a new starter cable (dia 3.5 mm /
1/8“, length 980 mm / 38.5“) as shown in the
illustration, tie a knot (as shown in the
illustration) in both ends, and tighten both knots.
Put on the cable drum 8 and turn it slightly until
the return spring engages.
Insert spring 7 in actuator 6 and insert together
into the cable drum 8 while turning slightly
counter-clockwise. Insert and tighten screw 5.
Tension the return spring clockwise. Turn the
return spring about 6 turns with the aid of the
cable, which should be pressed into the gap in
the cable drum.
Place the air guide 3 in the fan housing and
make sure the two recesses 4 engage.
Position the fan housing 2 correctly on the saw,
press against it slightly, and pull the starter
handle until the starter catches.
Tighten screws 1.
Reparaturanleitung PS-4600 / PS-5000 15
Repair manual PS-350 / PS-420
Page 16
yes
Is the spark plug dry and properly installed?
Is the spark gap correct? (should be 0.5 mm)
Is the spark plug oily or does it have carbon deposits on it?
Is there damage to the insulation of the high-voltage cable or the ignition cable,
or to the wires themselves?
Is the gap between the flywheel and the ignition module outside of the 0.25-0.3 mm range?
Remove flywheel and check. Is the flywheel damaged?
Is the positioning key damaged?
Continue with troubleshooting in fuel system (tank, fuel hose, carburetor).
Remove spark plug. Is the spark plug damaged? Is it the wrong kind of spark plug?
Is there carbon on the electrodes?
no
yes
no
yes
no
no
no
no
no
no
yes
yes
Dry spark plug cap and fasten firmly to spark plug.
If needed, replace the cap or cap spring.
Replace spark plug. Use ONLY a spark plug approved by DOLMAR.
See operating manual! Otherwise the ignition module might be damaged.
Eliminate the causes for carbon deposits on electrodes (bad two-stroke oil, wrong mix,
defective air filter, check carburetor adjustment).
Use DOLMAR high-performance two-stroke oil.
Adjust spark gap.
Wash spark plug in acetone. Do not sandblast!
If necessary, replace spark plug.
Eliminate cause: wrong carburetor setting, too much oil in fuel,
frequent short operations.
Replace spark plug and check ignition module for corrosion, if necessary replace.
Has the defect been remedied?
Replace high-voltage cable and/or ignition cable. Has the defect been remedied?
Check radial play of drive shaft, and repair if needed.
Replace ignition module if traces of overheating become visible.
Adjust gap between flywheel and ignition module correctly.
Replace flywheel or key. Before installation wipe cone seat at drive shaft
and flywheel with acetone or alcohol to remove any grease.
Tighten fastening nut to the correct torque! Has the defect been remedied?
Replace ignition module. Has the defect been remedied?
no
Install ignition testing lamp.
Alternatively, insert universal wrench between cylinder and hood. The wrench must
have metallic contact with the cylinder. Caution: Do not insert the wrench into the spark
plug hole or hold with hand.
Using insulated pliers, hold the unscrewed spark plug against the wrench.
Caution: Do not hold the spark plug directly against the hole. Detonation hazard!
Pull the starting cable smartly. Is there an ignition spark?
Is the gap uneven? Has the flywheel worn against the ignition module?
no
no
yes
yes
yes
no
no
07 IGNITION S
YSTEM
(TROUBLE
-
SHOOTING)
___
Reparaturanleitung PS-4600 / PS-5000 16
Repair manual PS-350 / PS-420
Page 17
soft surface, and knock the flywheel loose with
CAUTION: The cone of the crankshaft must
07 IGNITION S
YSTEM
___
Removing the flywheel
Remove starter see chap. 06.
Block the piston, see chap. 04.
Loosen the nut in the direction of the arrow
and remove it along with the washer.
Screw the disassembly mandrel (chapter 00
pos. 2) onto the threaded end of the shaft.
Do not screw the mandrel all the way down.
Leave about 2 mm between the mandrel and
the flywheel.
Hold the machine in one hand or place on a
a tap on the mandrel.
always be degreased before assembly.
Reparaturanleitung PS-4600 / PS-5000 17
Repair manual PS-350 / PS-420
Page 18
2
3
4
5
6
7
8
1
12
11
10
9
13
14
15
16
07 IGNITION S
YSTEM
mature against the gauge towards
Attach the short
___
Removing the ignition armature
Remove cover and air filter.
Unsrew screws 2 and 12.
Pull fuel lines 6 from the primer.
Push detent 7 on the primer 8 slightly and pull
out the primer.
Disengage short-circuit wire 10 from the
rocker 11 and pull the rocker up and out.
Unscrew screws 5 and 9.
Unscrew screw 4.
Pull off spark-plug cap 3 and unscrew spark
plug.
Push the spark-plug cap wire grommet out
towards the spark.plug hole.
The cover 1 can now be taken up and off.
Reparaturanleitung PS-4600 / PS-5000 18
Repair manual PS-350 / PS-420
Pull short-circuit wire 15.
Unscrew 2 screws on ignition armature 14.
Remove ignition armature and wire.
Installing the ignition armature
Note: The high-voltage cable is moulded onto
the ignition system and cannot be replaced
separately.
Insert the armature and turn the screws in
almost all the way.
Insert the setting gauge 16 (Kapitel 00 Pos. 3)
between the ignition armature and the
fylwheel.
Position the flywheel so that the magnet is
against the armature (gap 0.25 – 0.3 mm).
Press the ar
the flywheel and tighten the armature screws.
Then check the gap again to make sure it is
correct.
-circuit wire 15 and press the
rubber grommet into the carburetor base.
Page 19
Note:
5
9
8
10
6
7
4
1
2
3
4
08 CARBURETOR
___
Removing the intake manifold and
carburetor
CAUTION: Completely empty the fuel tank
before disassembling the carburetor!
Remove cover and air filter.
Move combination switch to safety position.
Unscrew 4 screws 1.
Remove intake manifold 2.
Pull fuel lines and pulse line 3 from the
carburetor.
CAUTION: There is fuel in the line. Catch
escaping fuel with a cloth.
Disengage throttle link 4.
Note: When reassembling, engage the
linkage in the marked hole (arrow).
Reparaturanleitung PS-4600 / PS-5000 19
Repair manual PS-350 / PS-420
Removing the carburetor bottom
Remove throttle linkage 4.
Remove cover (see chapter 07).
Pull short.circuit wire 5 from the ignition
armature.
Unscrew screw 6 and remove along with the
contact spring 7.
Unscrew screw 8.
Detach pulse line 9.
The carburetor base can now be removed
along with the combination switch.
Note: When assembling, make sure that the
short-circuit switch is pulled through the
rubber grommet as far towards the carburetor
as possible, in order to prevent the wire from
touching the cylinder.
Note: Do not twist the fuel line during
assembly.
If replacing the foam 10 in the
carburetor base, make sure the position is
correct. The opening should be towards the
suction channel, as shown in the illustration.
Page 20
General check
Check control lever for correct installation, see
ere
6
5
7
4
8
3
2
1
08 CARBURETOR
Control lever
Control lever
C
ontrol lever
Bas
ic
Setting
___
L= 1 1/2
H= 3
NOTE: Adjust the carburetor only
using a tachometer.
Pressure test
Connect the pressure gauge (chapter
00 item 8 oder 13) to the carburetor
fuel connection 1.
Set up a pressure of max. 0.5 bar.
If the pressure falls, check the
following parts:
•
Correct assembly of Control assy
(Control lever, Inlet needle, Lever
spring, lever axle)
•
Check seat of inlet needle for
dirt/foreign parts, clean if necessary
•
Replace control assy
• Replace gasket 6 and diaphragm 5
of the pump side
Correctly
(without Limiter Caps)
Too high
• Screen 7 for contamination
• Pulse hole for contamination
Check control parts
(control lever/inlet needle):
Check the tip of the inlet needle for wear.
illustration to the left.
If the control lever is too low:
• Lack of fuel
• Poor acceleration
• No maximum power
If the control lever is too high:
• Carburetor flooding
• Starting problems
• Poor idling
•
Poor transition
Check the pump diaphragm:
•
Control lever
If pump diaphragm is dented, torn, or creased,
• If valve flaps are bent,
replace the diaphragm and gasket
Check control diaphragm:
• If control diaphragm is bent or torn, or th
is obvious wear at the button 8.
• If it does not return to its original position
when pulled out of it,
Too low
replace the diaphragm and gasket.
Reparaturanleitung PS-4600 / PS-5000 20
Repair manual PS-350 / PS-420
Page 21
1
2
4
3
09 VIBRATION DAMPER
___
Disassembly
Springs 1 and 2
Remove the sprocket guard and chain brake
cover, see chap. 01.
Loosen screws with Torx screwdriver (chap.
00 pos. 1) and remove.cushion spring.
Spring 3
Remove starter housing (see chap. 06) and
hood (see chap. 07).
Loosen and remove screws with Torx
screwdriver (chap. 00 pos. 1).
Pull out cushion spring.
Spring 4
Remove the side brace cover.
Loosen and remove screw with Torx
screwdriver (chap. 00 pos. 1)
Remove cushion spring. Remove spring
retainer.
Note: During assembly, insert spring retainer
between the cushion spring and the cylinder.
Reparaturanleitung PS-4600 / PS-5000 21
Repair manual PS-350 / PS-420
Page 22
1
2
4
3
10 TANK
___
Grip mechanism
Unscrew screw 1 and pull off the top grip half
near the screw seat.
Note: When removing the throttle the following
must be done:
• Remove intake manifold and carburetor
• Remove hood and carburetor base
See chapters 07 and 08.
The throttle lever has a slot 2 at the hinge.
In assembly, first place the throttle lever
spring 3 on the throttle lever, then push the
lever onto the hinge iwth the slot. The throttle
lever must be turned by 180° to do this.
The throttle lever block 4 can easily be
pushed through the diagonals on the seat.
The spring is engaged in the throttle lever as
shown below.
Reparaturanleitung PS-4600 / PS-5000 22
Repair manual PS-350 / PS-420
Page 23
Attach the over/underpressure pump as
Close off the installation opening of the air valve
with your thumb (dampen it slightly).
change as long
pull it through the
s may damage the
5
8
6
7
10 TANK
Attach the over/underpressure pump (chap. 00
___
Removal
To remove the tank, first remove the hood (see
chap. 07), the starter housing (see chap. 06)
and the vibration damper.
Before separating the engine unit and the tank,
the lateral fastening screws on the front grip will
have to be unscrewed.
Pressure test
pos. 13) to one of the two fuel lines 5 . Seal off
the second line.
Set up a pressure of max. 0.3 bar.
If the pressure drops off, check the following:
• Air valve
• Bothe fuel lines
• Fuel nipple
• Tank cap seal
• Check tank for holes
Note: Detergent can be used to localise leaks.
Vacuum testing ventilation valve 6
described.
Set up a negative pressure of max 0.5 bar.
This negative pressure must not
as the opening is sealed. When you take your
thumb off the air valve, the negative pressure
must quickly return to normal.
Parts
To remove the suction head 7
tank opening with a hooked wire.
Note: Do not use pliers,as thi
line. Do not pull on the suction head or fuel line,
as this can pull off the fuel nipple inside the
tank.
Fuel lines 5 can be pulled off the fuel nipple.
Fuel line length:
Return L = 118 mm (dia. 2.5/5.5)
Supply L = 93 mm (dia 5.5 / 3)
Carefully lever out fuel nipple 8 with a sharp
flat-bladed screwdriv er.
Note: Do not lever against the line connections,
as this can break them off.
Lever off ventilation valve 6 with a small
screwdriver.
Reparaturanleitung PS-4600 / PS-5000 23
Repair manual PS-350 / PS-420
Page 24
1
2
3
11 CYLINDER / PISTON
___
Reparaturanleitung PS-4600 / PS-5000 24
Repair manual PS-350 / PS-420
Vacuum testing
If correct carburetor setting is not possible, it will
be necessary to test the sealing of the engine.
Remove hood (see chap. 07).
Remove carburetor (see chap. 08).
To seal off the exhaust side, insert the sealing
lip 1 (chap. 00 pos. 15) between the muffler and
the cylinder. First remove the muffler and
unscrew the fastening bolt from the cylinder.
To seal off the intake side, install the sealing
plate 2 (
carburetor.
chap. 00 pos. 14
) in the place of the
Connect the over/underpressure pump to the
connection on the sealing plate 3.
Seal off the pulse line and bring the cylinder to
top dead center.
Set up a pressure of max. 0.3 bar.
If the pressure rises within 20 seconds, the
following conditions may exist:
•
Radial ring leaking
•
Cylinder base gasket leaking
•
Crankcase gasket leaking
•
Crack in crankcase
•
Crack in cylinder
•
Spark plug leaking
•
Rubber intake on cylinder leaking
•
Defective pulse line
Note: Detergent can be used to localise leaks.
Page 25
with a rubber
1
2
3
11 CYLINDER / PISTON
___
Note: If there is a leak into the oil tank, it will
not be possible to fully identify the leak. If
pressure remains steady in the crankcase
after shutting off the oil line hole, for example
stopper (
see chap
. 05), it is an
indication that there is a defect in the
crankcase gasket to the oil tank.
Always perform sealing tests with
underpressure!
If a leak is diagnosed, it can be found
using overpressure and detergent or
similar liquid.
Reparaturanleitung PS-4600 / PS-5000 25
Repair manual PS-350 / PS-420
Page 26
5
6
4
7
8
11 CYLINDER / PISTON
ly oil the cylinder race
on
___
Removing the cylinder and piston
Disconnect the intake and exhaust sides.
Unscrew the spark plug.
Remove the ignition armature.
Disassemble the vibration damper between
the cylinder and front grip.
Unscrew 4 screws 4 and pull the cylinder up
and off.
Note: After pulling off the cylinder 6, support
the piston with the assembly tool (
pos. 6
).
chap. 00
Reparaturanleitung PS-4600 / PS-5000 26
Repair manual PS-350 / PS-420
Remove spring ring 5 with needle-nose pliers.
Assembling the cylinder and piston
Use a new gasket!
Note: The protuberance on the gasket must
point towards the induction side.
Before assembly, light
and piston!
Push assembly tool 7 under the piston.
Turn the opening on the piston ring towards the
piston ring lock.
Use the piston ring tensioner 8 to press the
piston ring together.
Push the cylinder onto the piston. Let the pist
ring tensioner slide down with it.
Remove the assembly tool and piston ring
tensioner and press the cylinder all the way
down.
Hand-tighten the screws 4 lightly crosswise,
and then tighten to the correct torque, again
crosswise.
Page 27
bearing onto the
insert into the heated housing without further
Always use a new gasket. After bolting the
3
4
5
MS
KS
1
2
12 CRANKCASE / CRANKSHAFT
___
Crankcase sides MS and CS are attached with
six screws 1.
Two pins 2 ensure proper fitting.
When assembling the ball bearings, note the
following:
• Press one ball bearing onto the clutch side
of the crankshaft. Press the
shaft using an assembly sleeve, pressing
only on the inner bearing ring. Place a
wedge between the crank webs.
• Heat the clutch side of the crankcase to
150-160° C using a hot-air blower or in an
oven. Evenly apply Loctite 620 to the outer
ring of the bearing (on the crankshaft), and
pressure.
Note: Before applying the Loctite 620,
degrease both bearings.
• Heat the magneto side of the crankcase to
150-160° C using a hot-air blower or in an
oven. Evenly apply Loctite 620 to the
bearings, and insert into the heated housing
without further pressure.
• Reattach the crankcase sides. Place a
wedge between the crank webs when
pressing.
crankcase sides together, cut off the flash 3.
DOLMAR offers complete crankcases with
preinstalled bearings as replacement parts.
Reparaturanleitung PS-4600 / PS-5000 27
Repair manual PS-350 / PS-420
Page 28
13 TORQUES
___
Fastener Part No. Size Qty.
Crankcase sides
Cylinder on crankcase
Carburetor bottom on crankcase
Muffler on cylinder
Front shell to muffler
Front shell to cylinder
Carburetor / intake manifold in carburetor flange
Intake manifold on carburetor bottom
Intake manifold to hood
Oil pump to crankcase
Oil pump cover to crankcase
Clutch to crankshaft
Transmission cover chain tensioner to
crankcase
Mounting bolt in bar flange
Mounting bolt in bar flange
Sprocket guard mounting
Chain brake cover
Ignition mounting in crankcase
Flywheel nut fastening
Starter housing to crankcase
Hood
Handguard bearing to magneto side
Grip/rear handle to tank
Front handle on tank, side
Front handle on tank, bottom
Front handle side cover on tank
Damping spring fastening on cylinder
Damping spring / tank, mag. side rear
Damping spring / tank, cyl. side front
Damping spring cylinder / handle side cover
Damping spring / crankcase, mag. side
Damping spring / crankcase, cyl. side
Damping spring / crankcase, cyl. side
Spark plug
Pawls to magnet wheel
Mounting bolt TLC
Reparaturanleitung PS-4600 / PS-5000 28
Repair manual PS-350 / PS-420
908.405.205
908.405.205
908.005.165
908.005.165
908.005.165
908.305.405
908.004.405
913.455.164
913.455.164
908.005.165
908.005.165
---
915.135.100
195.232.010
195.232.020
923.208.004
908.105.126
908.805.205
920.308.024
908.005.165
908.005.165
908.005.165
913.455.164
913.455.164
913.455.164
913.455.164
908.005.165
913.455.164
913.455.164
913.455.164
908.005.165
908.005.165
908.005.165
965.603.021
170.166.041
195.232.040
M 5 x 20 Torx
M 5 x 20 Torx with lock teeth
M 5 x 16 Torx
M 5 x 16 Torx
M 5 x 16 Torx
M 5 x 20 x 40 Torx
M 4 x 40 Torx
5,5 x 16 Torx
5,5 x 16 Torx
M 5 x 16 Torx
M 5 x 16 Torx
M 12 x 1 L with assembly wrench for centrifugal clutch
BZ 3,5 x 9,5
M 8 SK 6 / M8
M 8 SK 6 / M8 x 1
M 8, SW 13, 6KT-nut with flange
M 5 x 12 Torx
M 5 x 20 Torx
M 8 x 1 / SW 13
M 5 x 16 Torx
M 5 x 16 Torx
M 5 x 16 Torx
5,5 x 16 Torx
5,5 x 16 Torx
5,5 x 16 Torx
5,5 x 16 Torx
M 5 x 16 Torx
5,5 x 16 Torx
5,5 x 16 Torx
5,5 x 16 Torx
M 5 x 16 Torx
M 5 x 16 Torx
M 5 x 16 Torx
M 14 x 1,25 / SW 19
--
--
6 x
4 x
2 x
2 x
2 x
1 x
2 x
1 x
1 x
1 x
1 x
1 x
1 x
2 x
1 x
2 x
2 x
2 x
1 x
4 x
3 x
1 x
1 x
2 x
2 x
2 x
1 x
1 x
1 x
1 x
1 x
2 x
2 x
1 x
2 x
1 x
Torque
10 +/-1
12 +/-1
5 +/-0,5
8 +/-1
8 +/-1
8 +/-1
3 +/-1
3 +/-1
5 +/-1
5 +/-1
5 +/-1
35 +/-2,5
1,5 +/-0,2
15 +/-1
15 +/-1
1 +/-0,5
5 +/-0,5
5 +/-0,5
25 +/-1
5 +/-0,5
5 +/-0,5
5 +/-0,5
3 +/-1
5 +/-1
5 +/-1
3 +/-1
5 +/-0,5
5 +/-1
5 +/-0,5
5 +/-0,5
5 +/-0,5
5 +/-0,5
5 +/-0,5
15 +/-5
8 +/-1
10 +/-1
Page 29
NOTES
___
Reparaturanleitung PS-4600 / PS-5000 29
Repair manual PS-350 / PS-420
Page 30
NOTES
___
Reparaturanleitung PS-4600 / PS-5000 30
Repair manual PS-350 / PS-420
Page 31
NOTES
___
Reparaturanleitung PS-4600 / PS-5000 31
Repair manual PS-350 / PS-420
Page 32
___
DOLMAR GmbH • Postfach 70 04 20 • D-22004 Hamburg • Germany Form: 995 728 020
Reparaturanleitung PS-4600 / PS-5000 32
Repair manual PS-350 / PS-420
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