Dolmar PS-34 Operating instructions

Page 1
Repair Manual
11/99
PS-34

Page 2
Table of contents
Index Technical Data page 3
Special tools 4
Repair instructions, general 5
01 Chain brake 6
02 Centrifugal clutch 8
03 Oil pump 9 -11
04 Ignition system 11-13
05 Starting system 14-15
06 Carburetor / intake system 16-19
08 Rubber buffer, handles 20
09 Fuel tank, exhaust 21
10 Pistons and cylinders 22-23
11 Crankcase, crankshaft 24-25
Torques 26

Page 3
Technical Data
Stroke volume cm333
Bore mm 37
Stroke mm 31
Max. power at speed kW / rpm 1.3 / 9,000
Max. torque at speed Nm / rpm 1.7 / 6,500
Idling speed / Max. engine speed with guide bar and chain rpm 2,800 / 12,200
Coupling speed rpm 4,500
Sound pressure level LpA av at the workplace per ISO 7182 1) dB (A) 99
Sound power level LwA av per ISO 9207 1) dB (A) 105
Vibration acceleration ah av per ISO 7505 1)
- Tubular handle m/s24
- Rear handle m/s26
Carburetor (diaphragm carburetor) Type ZAMA
Ignition system Type PHELON
Spark plug Type NGK BPMR 7A
Electrode gap mm 0.5
or spark plug Type BOSCH WSR 6F
Fuel consumption at max. load per ISO 7293 kg/h 0.71
Specific consumption at max. load per ISO 7293 g/kWh 550
Fuel tank capacity l 0.37
Chain oil tank capacity I 0.25
Mixture ratio (fuel/two-stroke oil)
- when using DOLMAR oil 50 : 1
- when using other oils 40 : 1
Chain brake engages manually or in case of kickback
Chain speed 2) m/s 17,1
Sprocket pitch inch 3/8
Number of teeth Z 6
Chain type - see the Extract from the spare-parts list
Pitch / Driving element strength inch 3/8 / .043
Guide bar, length of a cut cm 30
Guide-bar type - see the Extract from the spare-parts list
Weight (fuel tank empty, without chain and guide bar) kg 4.7
1) Figures derived in equal part from idle, full-load, and top-speed operation.
2) At max. power
Technical data PS-34

Page 44
Setting gauge for split size
Flywheel / ignition armature
944 500 890
Special tools
Piston stop wedge
944 602 001
Assembly wrench for
clutch blades
944 500 695
Flywheel remover
944 500 880
Assembly and disassembly tool for
oil pump worm
950 500 060
Assembly sleeve 944 500 580
Torx bits unit T27 150 mm
944 500 865
Torx bits unit T27 50 mm
944 500 866

Page 5
Oil and fuel tank
To remove the starter, the oil and fuel
tank cover must be removed. If a residue
is to be left in the tanks, screw tank cover
back on after removing the starter.
Starter
For all work on the motor, ignition and
carburetor, oil pump and starter, the
starter must be removed after 4 screws
(5) have been removed.
5
General information on repairing the PS-34
The PS-34 chain saw is a small reasonably chain saw.
The objective in developing this saw was to provide a low-priced appliance that could
be assembled as easily as possible. Many of the design features are therefore based
on the concept of easy assembly.
The following tips summarise our experience in terms of carrying out repairs rapidly.
In general, we recommend that you use an electric screwdriver.
The air filter hood is fixed with 3 screws and
must be removed for all work on the motor. In
order to keep out dirt and foreign bodies,
always close the suction duct which is open to
the top.
142
3
Remove tubular handle.
The tubular handle is removed if work is
carried out on the carburetor, ignition or
motor. For this, remove 2 screws on the
clutch side (2) + (3), plus (4) on the
underside out of the motor housing.
55
5

Page 6
x
1
32
4
5
8
7
10 9a 9b
01-01 Removing the chain brake
Remove sprocket guard, nose bar and chair,
clear the chain intake area.
01-01 Removing the chain brake
Carefully lever out 4 pivots (x) on the
cover plate from the housing sleeves
using a long screw driver.
01-01 Removing the chain brake
The pivots (1) are fixed by a thicker
section in holes in the housing and hold
the cover plate. If pivots break off during
dismantling, replace the cover plate.
01-01 Removing the chain brake
Remove clutch drum (2) and centrifugal
clutch (3, see 02-01), take straining screw
(4) from housing pocket.
01-01 Removing the chain brake
Push out rear sleeve (6) with screw (5), re-
move front sleeve (7), remove Seeger ring (8)
of upper bolt (9a), pull out both bolts (9a + 9b),
remove spring (10) from brake lever from
housing.
01-01 Removing the chain brake
Loosen chain brake to relax packing
spring, loosen screw for hand guard (5)
and unscrew 2-3 rounds.
01 Chain brake
6

Page 7
01 Chain brake / clutch drum
02-01 Removing the centrifugal clutch
Remove guard ring (4) and washer (5)
and pull clutch drum with bearing off the
crankshaft.
02-01 Checking the clutch drum
Check drive pinion (6), running surface
(7) and external contour (8) (-> brake
spring) for wear and damage. Replace
worn or damaged clutch drums.
01-01 Removing the chain brake
Push cylindrical pin (1) from housing and
remove brake spring holder (2) with joint
piece.
1
2
01-07 Replacing the bolt
Tighten the 2 M8 nuts (3) on the bolt
against each other and unscrew bolt
3
4
5
6
78
02-01 Replacing the clutch drum
Before assembly, lightly grease the
bearings of the clutch drum (9) with
grease no. 944.360.000.
9
01-01 Checking the brake spring
Check brake spring for wear and dam-
age. Note: the chain brake is a safety
component, so worn or damaged brake
springs must be replaced.

Page 8
1
2
3
4
6
5
7
8
02-01 Removing the centrifugal clutch
Remove exhaust, block motor with piston stop
wedge (1). Loosen blades (2) individually with
special nut 944.500.695.
02-01 Mounting the centrifugal clutch
The thrust washer (3) must be inserted
before the cover washer (4). Make sure
that the assembly sequence is followed
and the blades properly installed.
02-01 Mounting the centrifugal clutch
Blade (5) + (6) w. DOLMAR marking
pointing towards the motor, blade (7) with
marking (8) outwards.
02-01 Mounting the centrifugal clutch
Tighten blades individually with the assem-
bly tool 944.500.695 to 20 +5 Nm.
02 Centrifugal clutch

Page 9
03-02 Removing the oil pump
To remove the oil pump, remove the
suction hose and cylinder, see 10-01.
03-02 Removing the oil pump
Pull oil pump out of oil suction pipe.
Check oil pump piston (3) for damage.
03-02 Removing the oil pump
Empty oil tank if necessary, pull suction
hose out of tank.
03-03 Assembling the oil pump
Before assembly, grease the oil pump
piston (3) and the housing well with
silicon past 980 007 100.
03-04 Air supply to and removal from
oil tank
Clean splint and hole.
1
2
23
03-02 Removing the oil pump
The oil pump piston is driven by the worm (1)
on the crankshaft. The pivot in the holder (2)
fixes the oil pump in the right position and
controls the lifting movement of the piston.
03 Oil pump

Page 10
x
3
21
4
--->
5
6
03-04 Removing the oil suction pipe
Remove the oil suction pipe from the
housing.
03-04 Replacing the oil suction pipe
Insert guide tie (1) into the housing
pocket, push connection nipple (2) firmly
into the hole (3).
03-04 Replacing the oil suction pipe
Grease the flange areas (x) for better
sealing and easier assembly with silicone
paste 980.001.100.
03-04 Installing the oil pump
Position oil pump on worm, insert holder
pivot into the hold (4) of the oil pump and
screw up.
03-04 Removing the worm
Twist the removal and assembly tool
950.500.060 onto the worm (left-handed
thread) and remove from the crankshaft.
03-05 Replacing the worm
Twist the worm (5) into the removal and as-
sembly tool until it is flush (left-handed thread).
Position assembly sleeve 944.500.580 (6)
onto the crankshaft. Push the worm onto the
crankshaft as far as it will go.
03 Oil pump

Page 11
04-04 Removing the spark plug
Remove motor hood. Remove spark plug
cap. Loosen and unscrew the spark plug with
a universal wrench 941 719 131 or similar
tool w. 19 mm opening.
04-04 Testing the ignition system with
test device
Connect test device. Operating lever (3)
must be in position ‘I’. Pull starter rope (4)
out quickly. If no power registered, check
wiring, repeat test with new ignition coil.
04-04 Removing the ignition system
Remove motor cover and tubular handle
and starter cover as described in intro-
duction.
04-04 Replacing the spark plug
Tighten the spark plug using universal
wrench 941.719.131 only or max. 20 Nm if
other tools are used.
04-04 Check spark plug
Check whether a spark (5) jumps across
at the electrode. If no spark, repeat test
with new spark plug. Clean or replace
dirty or damaged spark plugs.
1
2 3
4
04-04 Check spark plug
Connect spark plug (1) with spark plug cap
(2) and connect to earth Operating lever (3)
must be in position ‘I’. Pull starter rope (4)
quickly.
34
5
04 Ignition system
Warning: high voltage
Wear protective gloves
and use insulated tools!

Page 12
04-04 Mounting the flywheel
Before assembly, clean crankshaft pivot (1)
and flywheel cone (2). The flywheel contains a
device to prevent torsion. When positioning,
insert the torsion guard into the groove of the
crankshaft (3).
04-04 Removing the flywheel
Block motor with piston stop wedge (x)
944.602.001 and loosen flywheel nut.
04-04 Removing the ignition system
Pull off the short-circuit cable flat plug and
unscrew the 2 screws of the ignition
system.
04-04 Removing the flywheel
Screw flywheel remover 944.500.880
onto the crankshaft, pull flywheel upwards
and remove the flywheel from the cone by
tapping on the remover.
3
21
04-04 Mounting the flywheel
Set the crack between the flywheel mag-
net and the poles of the ignition coil at 0.2
mm using the setting gauge 944.500.890
(4).
4
04-04 Mounting the flywheel
Tighten the flywheel nut with 20 + 2.5 Nm.
04 Ignition system, flywheel
x

Page 13
04-04 Removing the short-circuit cable
Remove the contact spring (4) from the
housing pocket.
04-04 Replacing the short-circuit cable
The 2 core short-circuit cable connects the
contacts of the ignition coil (1) and earth (2)
with the stop switch (3).
1
2
3
04-04 Replacing the short-circuit cable
The short-circuit cable is taken under the
carburetor sleeve in a clamping strip to the
choke and operating lever.
4
5
5
04-04 Removing the choke lever
Remove the cable with the flat plug (5)
from the guide pocket (6). Push the choke
lever in the direction of ‘stop’in order to
swing the arm from the housing pocket.
04-04 Removing the short-circuit cable
The flat plug contact (5) is connected with
the contact spring. The round contact (6) is
inserted from the clutch side into the open-
ing in the choke lever.
5
6
04-04 Mounting the short-circuit cable
Check whether, in the STOP position, the
round contact in the choke lever is posi-
tioned on the metal tongue of the contact
spring.
7
04 Ignition system, short-circuit cable

Page 14
05-02 Removing the starting system
Remove the motor hood and tubular
handle as described in introduction.
05-02 Removing the starting system
Loosen 4 screws and remove starter
cover.
05-02 Removing the cable drum
Pull out starter rope between cable drum
and starter housing. Relax rewind spring
by slowly letting the cable drum run back.
05-02 Insert rewind spring
a) Wind up rewind spring by hand.
Wind up spring in anti-clockwise direction.
Insert spring eye in housing. Grease
spring with grease no. 944.360.000.
05-02 Removing the starting system
Pull out the starter rope as far as it will go
and hold the drum tight.
05-02 Removing the cable drum
Loosen screw (1) and remove cable drum.
Take spring unit out of pocket with pincers.
1
05 Starting system

Page 15
05-02 Mounting the starter
Insert cable drum with knotted starter
rope, let the spring click into the carrier
and tighten screw.
05-02 Mounting the starter
To check the pretension of the rewind
spring, pull the starter rope out completely.
Cable roller must be able to turn at least
another 1/2 turn further.
05-02 Inserting the rewind spring
b) as spare part. Insert the spring unit secured
with wire, insert spring eye in housing and
push spring into housing pocket. Grease with
grease no. 944.360.000.
05-02 Mounting the starter
Take starter rope through the eyelet, pull
starter handle over the rope and secure
with knot.
05-02 Mounting the starter
Tension rewind spring by turning several
times, allow starter rope to slide onto cable
drum.
05-02 Mounting the starter
If the cable drum cannot turn any further,
reduce the pretensioning by letting out a
section of starter rope.
05 Starting system

Page 16
06-02 Removing the carburetor
Remove the motor hood and tubular
handle as described in introduction.
06-02 Removing the carburetor
Empty tanks if necessary. Remove side cover
after loosing the 4 screws. If oil or fuel is left in
the tank, replace tank cover.
06-02 Removing the carburetor
Pull the fuel line to the carburetor (1) and
the hose to the primer (2) off the outlet
using pliers.
06-01 Setting the carburetor
The injector needles L + H and the stop
screw S can be reached via holes in the
tubular handle strut.
S
L
H
2
1
06-02 Removing the carburetor
Pull fuel tank out of the housing opening
and place so that no fuel can leak out.
06-01 Setting the carburetor
For the basic setting, screw in both screws as far as
they will go. Then unscrew both screws 1 turn. If the
motor turns too quickly (taking the chain with it) or too
slowly (the motor dies off), adjust the screw S.
06 Carburetor / intake system

Page 17
06-02 Removing the carburetor
Pull the contact spring (1) of the choke
lever from the eye in the motor housing
using pliers.
1
06-02 Removing the carburetor
Push the choke lever in the direction of ‘Stop’
in order to swing the arm out of the housing
pocket. Remove cable with flat plug (2) from
guide pocket (3).
2
3
06-02 Removing the carburetor
Pull choke lever from housing with slight
turning movements.
06-02 Removing the carburetor
If necessary, pull the round plug contact
inserted from the back out of the pocket
using pliers.
06-02 Removing the carburetor
The cable is taken under the carburetor clip.
To stop it getting in the way during subse-
quent work, fix with adhesive tape position
underneath, if nec. remove contact spring
and choke lever.
06-02 Removing the carburetor
Completely loosen 2 vertical fixing screws
for the connecting muff (4).
4
06 Carburetor / intake system

Page 18
06-02 Removing the carburetor
The carburetor clip (3) with the suction
hose (4) remains on the cylinder. Make
sure that the loose insert (5) does not get
lost.
06-02 Removing the carburetor
Remove connecting muff upwards with a
slight movement to the left.
06-02 Removing the carburetor
Remove carburetor screw and remove the
carburetor from the carburetor carrier,
twisting slightly.
06-02 Removing the carburetor
Loosen 2 horizontal screws (1). The right
screw is reached through the slit between
the tank and the motor housing.
1
06-02 Removing the carburetor
Loosen the two horizontal screws until the
heads are exactly on a level with the
external contour of the connecting muff
(2). Only in this way can the connecting
muff be removed.
2
3
4
5
06-02 Removing the carburetor
Loosen the clip fixing of the primer (6)
and remove with hose.
6
06 Carburetor / intake system

Page 19
06-03 Pump side of the carburetor
Unscrew cover (9), remove gasket (10)
and diaphragm (11). Clean filter in bottom
of carburetor (12).
06-02 Installing the carburetor
Position the connecting muff so that it is slightly
tilted to the left so that the back right-hand
double strut of the connecting muff (1) is posi-
tioned behind the plate of the carburetor clip.
1
06-02 Installing the carburetor
Insert the connecting muff with a slight
twist to the right.
06-03 Control side of the carburetor
Unscrew cover (2), remove diaphragm (3)
and gasket (4). Remove screw (5). Remove
the admission needle (6) with spring (7),
arm and axle (8).
2
3
4
56
8
7
12 11 10 9
06-03 Checking the admission needles
for leaks
Pull fuel line off carburetor nipple and put
on hose of test appliance 944.603.020.
Check that 0.5 bar is maintained over a
minute.
06-08 Removing the throttle linkage
Remove the handle to the side (14). With
assembly, position the angle of the throttle
linkage (15) behind the plate of the throttle
grip (16). The throttle linkage is inserted in
pockets on the housing floor (17).
14
15
16
17
06 Carburetor / intake system

Page 20
08-02 Removing the rubber buffer
Remove 2 screws (1) and sleeves (2).
Fold back handle to the side so that the
throttle linkage slides out of the throttle
guide.
08-08 Dismantling the handle
The throttle grip (10) and catch lever (11)
are inserted in handle guides with a
spring (11).
11
08-02 Rubber buffers
3 hollow rubber buffers (4) on the clutch
side are inserted in the housing.
4
08-08 Dismantling the handle
The grip shell (6) is built together with the
handle (9) with 2 brackets (7) and pins (8).
Lever the housing apart from the inside.
5
5
7
6
9
11
10
12
08 Rubber buffer /handles
08-08 Dismantling the handle
The pivots of the grip are held tightly in
the sleeves. Increase leverage force
gradually until pivot clicks out. If brackets
or pivots break, replace housing.
08-02 Rubber buffers
On the magnet side, 1 hollow rubber
buffer (5) is inserted in the starter hous-
ing.