EMAK GS35, MT350, GS350, MT3500 Workshop Manual

WORKSHOP MANUAL

Chainsaw

GS35 – GS350 – MT350 – MT3500

General failures’ analysis

GS35 – GS350 – MT350 – MT3500 chainsaws

Suggested tools

General failures’ analysis

I.
II .
II I. Electronic tachometer: for 2 and 4 stroke engines, measurement range from 100 to 30,000 RPM

I.

Emak tool kit
Compression tester: to check thermal group

II.

p/n 3055125

III.

p/n 001000785

GS35 – GS350 – MT350 – MT3500 chainsaws

p/n 001000392A

Index

General failures’ analysis

1) Performance

a) Compression test
b) Cylinder and piston inspection
c) Cylinder and piston assembly
d) Cooling system cleaning
e) Muffler inspection

2) Fuel system

a) Fuel and fuel filter inspection
b) Fuel system test
c) Tank breather inspection
d) Engine seal test
e) Manifold inspection

3) Ignition system

a) Starter housing inspection
b) Spark plug inspection
c) Spark test
d) Flywheel-coil air gap inspection
e) Flywheel key inspection

4) Oil pump, bar and shock absorber

a) Oil tank breather inspection
b) Sprocket inspection
c) Chain brake inspection
d) Oil pump and oil filter inspection
e) Worm gear inspection
f) Shock absorber replacement
g) Lubrication and bar maintenance

5) Tuning

a) Air filters inspection
b) Needle valve inspection
c) Carburetor inspection
d) Suggested tools for carburetion setting
e) Carburetion tuning

6) Tightening torques

7) Trouble shooting

a) The engine does not start
b) Low performance
c) Additional problems

GS35 – GS350 – MT350 – MT3500 chainsaws

1) Rendimento

General failures’ analysis

a) Compression test
b) Cylinder and piston inspection
c) Cylinder and piston assembly
d) Cooling system cleaning
e) Muffler inspection

a) Compression test

•

Apply the Emak compression
tester (I) on cylinder. Pull
energetically the rope 10 times

•

Verify that the compression
value in not less than 7,5 bar –
110 psi

•

If the value in higher than
7,5 bar – 110 psi, start
inspection d), if lower, carry on
with inspection b)

I

p/n 001000392A

GS35 – GS350 – MT350 – MT3500 chainsaws

b) Cylinder and piston inspection

•

Verify the diamond scoring on piston and the nickel-lining on cylinder.
Replace if necessary

•

Verify the piston rings wear using feeler gauge (gap max 1,0 mm)

Warning: during assembly
make sure the circlip has the
feet pointing up

General failures’ analysis

Attention: de-grease the contact surfaces of the

cylinder and the cover. Use a liquid gasket to re-seal,
be careful with the quantity so it does not pollute
internal engine parts

GS35 – GS350 – MT350 – MT3500 chainsaws

c) Cylinder and piston assembly

Warning:

The arrow on the top of the cylinder points towards

the exhaust port.

General failures’ analysis

Tightening torque cylinder - screws

0,6 Kgm (52,08 in lb) + Loctite 243

The arrow must point towards the exhaust.

GS35 – GS350 – MT350 – MT3500 chainsaws

Warning:

d) Cooling system cleaning

Dismount the cylinder's cover. Blow, with
compressed air, cylinder fins, starter case and
flywheel

Important:

• Clean weekly the cooling system, more

frequently in heavy duty work conditions

• Use Loctite 243 to tighten plastic component

Tightening toque cover-basement

0,4 kgm (34,72 in lb) + Loctite 243

General failures’ analysis

Tightening torque

Cover

0,4 kgm (34,72 in lb)

+ Loctite 243

GS35 – GS350 – MT350 – MT3500 chainsaws

e) Muffler inspection

Catalytic muffler

Verify the conditions of the muffler (dirt / oily)
change if necessary

Non-catalytic muffler

If the muffler is blocked or damaged, clean or replace it

General failures’ analysis

Tightening torque cover muffler-muffler

0,6 kgm (53,10 in lb) + Loctite 243

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to index

2) Fuel system

a) Fuel and fuel filter inspection
b) Fuel system test
c) Tank breather inspection
d) Engine seal test
e) Manifold inspection

a) Fuel and fuel filter inspection

•

Verify fuel quality odor

•

Dismount and check periodically the fuel filter
and the sintered internal filter. In case of dirt or
oxidation, replace it

General failures’ analysis

Sintered
internal
filter

b) Fuel system test

•

Apply the pressure gauge at the fuel line. Check
any possible leakage at 0,5 bar

•

If the pressure is not stable, it may indicate
worn fuel system or loose at the carburetor
parts

Go to

Carburetor inspection

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

c) Tank breather inspection

•

Dismount the breather and check the components

•

Apply the pressure gauge (I), supplied with Emak tool kit, at the breather valve and verify the correct
working in both ways. Replace or clean if necessary

I

p/n 1043900

Breather sealing test:

0,2 – 0,3 bar

Breathing system test:

0,00 bar

GS35 – GS350 – MT350 – MT3500 chainsaws

d) Engine seal test

•

Remove the parts as per the photo. Close off
the inlet port with the correct flange from the
tool kit (I and II)

General failures’ analysis

•

Close the exhaust port by putting the flange
between the muffler and cylinder III (flange in
tool kit). Refit the muffle with the 3 screws M5x25

III

p/n 001000018

II

p/n 094500388A

GS35 – GS350 – MT350 – MT3500 chainsaws

IV

n°3 screws M5x25

Warning:

During the seal test use

only a light torque of

0,4 Kgm (35 in lb)

•

Fit the pressure gauge (V) to the inlet and apply 0.5 bar. The pressure should not descend

General failures’ analysis

GS35 – GS350 – MT350 – MT3500 chainsaws

V

p/n 1043900

General failures’ analysis

e) Manifold inspection

Check the manifolds for wear. Verify that the manifold’s rubber is not deteriorated or hardened and check
that there are no cuts or holes. Replace if necessary

Make sure the impulse path is

correctly inserted into the

GS35 – GS350 – MT350 – MT3500 chainsaws

Warning!

cylinder hole.

Back to index

3) Ignition system

a) Check housing inspection
b) Spark plug inspection
c) Spark arrester test
d) Flywheel-coil air gap inspection
e) Flywheel key way inspection

a) Starter housing inspection

Remove housing. Inspect parts for wear. If
necessary clean or replace

General failures’ analysis

Important: make sure the spring does not wind fully

with the rope fully out

Wind the spring 6

times. Verify that

the spring turns on

½ turn

ø 3,0 x 960 mm

Counterclockwise
turn to release
the spring

Important: grease moving parts

Clockwise turn
to wind the
spring

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

b) Spark plug inspection

Remove the spark plug and check the gap
between the electrodes (0,5 – 0,7 mm)

(0,5 – 0,7 mm)

RCJ-7Y

c) Spark test

•

Fit the tester (I) between spark plug and spark
plug cap. Pull the rope and verify the current

•

Replace the spark plug if necessary. Verify that the
spark plug thermal grade and type (resistive – R)
are correct

•

Check that the spark plug pipe is correctly
connected, cables are not damaged and coil works
properly

I

cod. 001000515R

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

d) Flywheel-coil air gap inspection

•

Check the air gap using the shim (II-0,3 mm)

•

Adjust if not correct

Tightening torque flywheel-nut

1,9 kgm (168,2 in lb)

e) Flywheel key way inspection

•

•

II

p/n 001000004

Remove flywheel with corrector tool (III)
Inspect key way’s condition and position. If
necessary, replace or adjust

III

p/n 001000782

Tightening torque coil-screws

0,4 kgm (34,72 in lb) + Loctite 243

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to index

4) Oil pump, bar and shock absorber

a) Oil tank breather inspection
b) Sprocket inspection
c) Chain brake inspection
d) Oil pump and oil filter inspection
e) Worm gear inspection
f) Shock absorber replacement
g) Lubrication and bar maintenance

a) Oil tank breather inspection

•

Clean with compressed air

•

Verify the quality of the bar and chain oil

General failures’ analysis

I

Warning!

Make sure the O-ring (I) is

seated before inserting the tube

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

b) Sprocket/power mate ring inspection

Check the sprocket/power mate ring wear
periodically. Replacement is suggested every
100 hrs or before

c) Chain brake inspection

Check the brake band, the plate and the
protection’s rubber for wear. This must be
changed if the wear limit is less than 0,6 mm

GS35 – GS350 – MT350 – MT3500 chainsaws

d) Oil pump and oil filter inspection

•

Use the piston stop (I) in the spark plug hole. Remove the clutch anticlockwise with tool (II)

General failures’ analysis

I

p/n 001000684

Tightening torque clutch

2 Kgm (177,0 in lb) + Loctite 243

II

p/n 3055133

Warning! Make

sure the spacer

washer is fitted (I)

I

GS35 – GS350 – MT350 – MT3500 chainsaws

•

Remove the oil pump. Check the pump and worm gear.

•

Inspect the supply hose and filter, clean.

Tightening torque screws oil pump

0,45 kgm (39,83 in lb) + Loctite 243

General failures’ analysis

Warning!

Use a liquid gasket to seal in the

hose to the saw body

GS35 – GS350 – MT350 – MT3500 chainsaws

e) Worm gear inspection

If worn or broken replace:

•

Remove with the correct tool from the tool box
(I)

•

Insert the worm gear into the fitting tool
(I) leave about 2 mm sticking out.

•

Fit the worm gear spring on the
crankshaft until the end of the spring
touches the crank seat (Photo 1-2).

•

Screw in the tool until stop (I) to give
the correct pitch to the worm gear.

General failures’ analysis

I

p/n 3055133

Photo 1

GS35 – GS350 – MT350 – MT3500 chainsaws

Photo 2

f) Shock absorber replacement

In case of wear or breakage replace the parts

General failures’ analysis

GS35 – GS350 – MT350 – MT3500 chainsaws

g) Lubrication and bar maintenance

•

Lubricate the sprocket nose

•

Keep the rail and the lubrication holes cleaned

•

Check the parallelism of the guide bar and for sharp metal edges

•

Turn the bar every 8 hrs to grant uniform wear

Keep
clean

O

S

S

A

GR

General failures’ analysis

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to index

5) Tuning

a) Air filters inspection
b) Needle valve inspection
c) Carburetor inspection
d) Suggested tools for carburetion setting
e) Carburetor tuning

Tightening torque

Support air filter-insulator

0,2 Kgm (17,7 in lb)

+ Loctite 243

General failures’ analysis

a) Air filters inspection

•

Sponge air filter (A): clean with
Emak degreaser, rinse with
water and blast dry with
compressed air

•

Cloth air filter (B): shake it and
clean it with a soft brush

•

Replace the filter when damaged

Tightening torque

Support air filter-carburetor

0,4 Kgm (34,72 in lb)

+ Loctite 243

A

GS35 – GS350 – MT350 – MT3500 chainsaws

B

General failures’ analysis

b) Needle valve inspection

Check the right position of the valve using a
caliper. Adjust if necessary

Needle

c) Carburetor inspection

Check and clean all components (diaphragm,
needle, filter). Use the repair kit to replace worn
components. If the carburetor is oxidized, replace
it

OK REPLACE

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to fuel system

d) Suggested tools for carburetor setting

Special screwdriver (I): for adjustment the jets “L” e “H”

General failures’ analysis

Insert the special

screwdriver (as shown

on the photo) and

adjust the jets

I

p/n 3055130

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

e) Carburetor tuning

Correct tuning of the EURO 1 (direttiva 97/68/CE + 2002/88/CE) and EURO 2 (direttiva 97/68/CE + 2002/88/CE
+ 2004/26/CE).

The jets have the following factory registration: L = 1+3/8±1/4 H=1±1/4

When, following a repair or engine overhaul, you are obliged to re-tune the carburetor to its’ original setting

Idling adjustment (L)

1. Start the unit and warm up for 60 seconds. If the engine stop, readjust T screw

2. Close the L jet until the maximum number of rpm is reached (stop rotating the jet before the rpms drop or

the unit stalls);

3. Adjust the T screw until the unit reaches an idle rpm between: 3700 and 4200 RPM

4. Open the jet L until the rpm go from 3700/4200 to 2800/3100 RPM

Maximum adjustment (H)

5. Adjustment of the jet H for wide open throttle operation whit bar (standard 16” - 41 cm) and chain:

10600 RPM with the new motor and 12100 RMP with run-in engine

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to index

Tightening torques

(kgm) – (in lb) / lubrication

* = Loctite 243

G = Grease
O = Oil

General failures’ analysis

6) Tightening torques

2 – 177,0

0,4 - 34,72 *

0,4 - 34,72 *

1,9 - 168,2 *

0,25 – 22,13 *

O

0,6 - 52,08 *

GS35 – GS350 – MT350 – MT3500 chainsaws

0,25 – 22,13 *

0,25 – 22,13 *

General failures’ analysis

0,6 - 52,08 *

0,2 – 17,7 *

0,4 - 34,72 *

Tightening torques

(kgm) – (in lb) / lubrication

* = Loctite 243

G = Grease
O = Oil

GS35 – GS350 – MT350 – MT3500 chainsaws

0,7 – 61,96 *

General failures’ analysis

0,35 –

30,98 *

0,35 –

30,98 *

0,4 - 34,72 *

0,7 – 61,96 *

0,35 –

0,04 – 3,54

0,4 – 34,72 *

Tightening torques

(kgm) – (in lb) / lubrication

0,35 – 30,98 *

30,98 *

* = Loctite 243

G = Grease
O = Oil

GS35 – GS350 – MT350 – MT3500 chainsaws

0,45 - 39,83 *

General failures’ analysis

Tightening torque

(kgm) – (in lb) / lubrication

* = Loctite 243

G = Grease
O = Oil

0,5 – 44,25 *

1,5 – 132,76

2 - 177,0 *

G

GS35 – GS350 – MT350 – MT3500 chainsaws

0,25 - 22,13 *

Back to index

General failures’ analysis

7) Trouble shooting: ENGINE DOES NOT START

Symptoms Causes Remedies Go to

1. The engine does not

turn over

2. There is no

compression

3. No spark

4. Fuel does not reach

the carburetor, the
machine stops after 5
minutes

5. Wrong carburetion

setting or erratic
throttle response

1.a Starter assy defect or

broken starter rope

1.b Internal damage

2.a Spark plug looses

2.b Piston ring, cylinder and

piston worn

3.a Ignition switch is in “OFF”

position

3.b Ignition system defected

3.c Broken spark plug or

wrong type

4.a Fuel filter or breather

blocked

4.b Fuel system is leaking air

4.c Wet spark plug, flooded

cylinder

5.a Air filter dirty

5.b Wrong L and H setting

5.c Carburetor problems

5.d Manifold problems

1.a Check starter assy or starter rope

replacement

1.b Check thermal group and replace

worn components

2.a Tighten spark plug. Compression

test

2.b Replace worn or damaged parts.

Compression test

3.a Switch “ON” and restart

3.b Inspect and/or replace

3.c Replace the spark plug

4.a Clean or replace

4.b Tightness test on fuel system

4.c Carburetor inspection (point 5.c).

Take off spark plug, rotate the engine,
blow inside cylinder passing through
spark plug hole, dry the spark plug
and restart

5.a Clean or replace

5.b Adjust the carburetion according

the above

5.c Carburetor inspection

5.d Manifold tightness

Section 3

Section 1

Section 1

Section 1

Section 3
Section 3

Section 2

Section 2
Section 5

Section 5
Section 5

Section 5
Section 2

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

Trouble shooting: LOW PERFORMANCE

Symptoms Causes Remedies Go to

1. Engine

overheating

2. Engine

performance is
not stable

1.a Carburetor mixture too lean

1.b Air leaking in the engine or in

fuel system

1.c Wrong oil-fuel ratio

1.d Fan, starter housing, cylinder

fins dirty or damage

1.e Carbon deposit on piston

2.a Dirty air filter

2.b Loose spark plug or damaged

2.c Water in the fuel

2.d Seizure

2.e Faulty carburetor or diaphragm

1.a Set the carburetor

1.b Find air leaking and eliminate it

1.c Replace with fresh fuel and right

oil ratio

1.d Clean or replace it

1.e Eliminate deposit

2.a Clean or replace

2.b Tighten or replace

2.c Clean the carburetor and replace

fuel

2.d Replace the components

2.e Check and replace

Section 5

Section 1

Section 2

Section 1

Section 1

Section 5

Section 3

Section 5

Section 1

Section 5

GS35 – GS350 – MT350 – MT3500 chainsaws

General failures’ analysis

Trouble shooting: ADDITIONAL PROBLEMS

Symptoms Causes Remedies Go to

1. The chain does not

work correctly or does not
rotate

1.a Bended or worn bar

1.b Lubrication system blocked

1.c Worn sprocket

1.d The chain is not sharp

1.e Chain to tight

1.a Replace or maintain

1.b Clean or replace

1.c Replace sprocket

1.d Sharpen the chain

1.e Correct tension/assembly

bar and chain

Section 4

Section 4

Section 4

Owner’s
manual

Owner’s
manual

GS35 – GS350 – MT350 – MT3500 chainsaws

Back to index