Rotek EG4-5 Series Operating instructions

Air-cooled single cylinder gasoline engine
EG4-5 series
User- and maintenance manual
LT1812, effective April 2021
EG4-0210-5
EG4-0270-5
EG4-0420-5

DE2
Introduction
Dear Customer,
Please take time to read this manual carefully and thoroughly. It is
important to know about the instructions for correct installation of
your device, its components as well as proper and safe handling,
before putting it into operation.
This manual should be kept close to your device, to use it as a re-
ference if necessary and, if the device is sold on, to hand it on to
subsequent owners.
Operation and maintenance of this device involves dangers, which
are explained via symbols in this manual. The following symbols are
used in this text. Please read these instructions very carefully.
Security precaution
Dangers are marked by this symbol.
General advice
User advice is marked by this symbol.
We worked on the contents of this handbook to make sure your
device fits the described device. However, differences cannot be
ruled out so that we do not guarantee entire congruence of device
and manual. The information in this handbook is constantly review-
ed and updated when necessary. Corrected versions are available
on our website. Should questions come up about the device or its
proper handling, please contact us before installing or using it.
All pictures are used as symbols and may not look exactly the same
as your device. Technical changes, errors and misprints reserved.
Damage done to the device due to ignorance of the instruc-
tions in this manual will not be covered by its warranty. We
assume no liability over damage caused by wrong handling.
This manual may not be reproduced in any form, neither partially nor
completely, using any electronic or mechanical means whatsoever,
without permission in written form by Rotek. Ignoring this is a viola-
tion of copyright laws and will be prosecuted. All rights, particularly
the right of reproduction, reserved.
Inspection of delivered products
After receiving the device, it is recommended to check whe-
ther the goods correspond to the components mentioned in
the order, waybill or delivery note. Remove the packaging
carefully to make sure no damage is done to the device. Fur-
thermore, make sure to check the device for any transport
damage. If the delivery is incomplete or flawed, do not hesi-
tate to contact your retailer.

3DE
Index
1. Safety Instructions 4
1.1. Equipment 4
1.2. Risks from noise development 4
1.3. Risks posed by moving parts 4
1.4. Risks posed by gas emissions 4
1.5. Risks posed by fuel 4
1.6. Risks posed by high temperatures 4
1.7. Risks posed by exhaust gas 4
1.8. Maintenance intervals 4
1.9. Disposal of toxic waste 4
2. Transportation and storage 5
2.1 Transportation for assembly 5
2.2. Storage as new device 5
2.3. Storage after the device has been used 5
2.3.1. Downtime for up to 2 weeks 5
2.3.2. Downtime for up to 3 months 5
2.3.3. Downtime for up to 6 months 5
2.3.4. Downtime for more than 6 months 5
3. Specification 6
3.1. Technical data 6
3.2. Performance curves 7
3.3. Flange and shaft measurements 8
4. Installation 9
4.1. Preparation 9
4.2. State of installation site 9
4.2.1. In- and outtake Ventilation 9
4.3. Motor mounting 9
4.4. Exhaust gas system 9
4.4.1. Mounting the muffler 9
4.4.2. Information about other exhaust gas systems 9
4.5. Fuel System 9
4.6. Coupling 10
4.6.1. Maximum axial and radial load 10
4.6.2. Balancing 10
4.6.3. Direct coupling 10
4.6.4. Operating with a pulley 10
4.7. Concluding mechanical installation instructions 11
4.8. Mounting the oil-sensor controller 11
4.9. Electrical Assembly (only for “E” version) 11
4.9.1. Electrical connection (chords) 11
4.9.2. Starter battery 11
4.9.3. Mounting of optional Startbox 11
5. Usage 12
5.1. Illustration 12
5.2. Information about engine performance 13
5.3. Information about starter battery (optional) 13
5.4. Check-ups before every start-up 13
5.4.1. Engine oil 13
5.4.2. Fuel 13
5.4.3. Other check-ups 13
5.5. Start-up 13
5.5.1 Special information about initial start-up 13
5.5.2. Starting the engine 13
5.5.2.1. Hand start (all versions) 13
5.5.2.2. Electric start (only motor version “E”) 13
5.5.3 Stopping the engine 13
6. Maintenance 14
6.1. Instructions about maintenance 14
6.2. Precautions 14
6.3. Starter battery 14
6.4. Cleaning the crankcase 14
6.5 Upkeep 14
6.5.1 Changing the engine oil 14
6.5.2. Check the ignition (spark) 14
6.5.2.1. Spark plug chart 15
6.5.2.2. Appearance of the spark plugs 15
6.5.2.3. Solving ignition problems 16
6.5.2.4. Starter malfunction 16
6.5.2.5. Battery does not charge 16
6.5.2.6. Circuit diagram - version "H" 17
6.5.2.7. Circuit diagram - version "E" 17
6.5.3. Fuel Supply 17
6.5.3.1. Cleaning the carburetor 18
6.5.4. Cleaning and exchanging the air filter 18
6.5.5. Proper timing/adjusting the valves 18
6.5.6. Speed setting 19
6.5.7. Governing behaviour 19
6.5.8. Muffler and colours of exhaust fumes 19
6.5.9. Other 20
6.5.10. Engine torque and measured values 20
6.6. Possible errors and their solutions 21
6.7. Maintenance intervals 22
7. Appendix 23
7.1. Warranty conditions 23
7.2. Declaration of conformity 23

DE4
1. Safety Instructions
The guidelines in this manual have to be added to the valid local legal
requirements and technical standards. They do not replace any stan-
dards or additional (also legal) regulations, which were adopted as
safety measures.
1.1. Equipment
Always wear tight-fitting clothes during maintenance and make sure
their ends are closed with elastic bands.
When working on the device always wear safety shoes, gloves, a hel-
met and hearing protection in accordance with the applicable regulati-
ons to avoid accidents at work.
Make sure that a first aid kit and a working fire extinguisher are close
by before starting to work on the device.
1.2. Risks from noise development
The operating noise of the motor can cause damage to your hearing.
Do not linger around a running engine and always wear ear protection.
The engine must never be operated without a muffler.
Make sure that all legal regulations relating to the local noise level are
obeyed before starting up the device.
1.3. Risks posed by moving parts
Never perform work on moving parts.
The engine must never be put into operation when the protective co-
vers are open or loose.
Never approach the machine in operation wearing ties, scarves, bra-
celets etc. These could get caught on moving parts and cause serious
injuries.
1.4. Risks posed by gas emissions
To avoid the risks posed by dangerous gases:
Make sure that the location of the unit is well ventilated (in emergenci-
es using a forced ventilation system)
Avoid inhaling dangerous gases (by wearing breathing protection)
Verify that there are no hazardous gases present at the installation site.
1.5. Risks posed by fuel
It is necessary to shut down the engine during refuelling. Let the device
cool down for at least 5 minutes before refuelling.
Do not smoke in close proximity to the device, keep it away from fire
and ignition sources. Gasoline is flammable and poisonous! Moreo-
ver, lead acid batteries develop explosive gases when charging and
discharging.
Never spill fuel onto the engine or the muffler when refuelling.
Never put the engine in operation when there are apparent leaks in the
lines supplying oil or gasoline.
Never spill gasoline or oil. Do not inhale fumes, do not swallow and
avoid skin contact. After swallowing any amount of gasoline or oil, im-
mediate medical attention is required! Do not attempt to vomit after
swallowing!
Should fuel spill over your skin or clothes immediately rinse with soap
and water, and change your clothes.
Allways keep the floor on the site of the device clean – spilt oil or
gasoline should be removed as soon as possible.
When using an additional external tank make sure it is installed and
connected in accordance with the valid standards and regulations.
1.6. Risks posed by high temperatures
The engine must only be used in places where no untrained people,
passers-by or children are at risk.
Children are not allowed to stay in close proximity to the engine.
Never store combustible or flammable substances (gasoline, oil, paper,
wood chips etc.) in the vicinity of the device.
Note that gasoline, oil, engine and exhaust pipe are hot after operation
– avoid skin contact – there is a risk of burning or scalding.
Always keep a minimum safety distance of 1 meter to walls or similar
structures to avoid overheating the engine.
Never cover the engine during operation – there is a risk of overhe-
ating!
1.7. Risks posed by exhaust gas
The engine must not be used in poorly ventilated areas (such as en-
closed spaces, tunnels, containers), unless those installations were
expressly approved by ROTEK.
Exhaust gases are toxic. They can cause loss of consciousness or even
death. When using the device in closed or partially closed spaces,
make sure that the exhaust gases are led outside by means of a leak-
free line. Regard the maximum permitted exhaust back pressure in or-
der to prevent the motor from overheating. Make sure that the exhaust
adaption (muffler, pipe) is free from combustible materials and that the
escaping gases do not pose a threat. Observe the pertinent standards
and regulations at all times.
1.8. Maintenance intervals
If the mandatory maintenance intervals were not complied with it is
forbidden to start the engine – vapours of unspent fuel (developed by
incorrectly adjusted valves for example) are explosive!
Never start the engine without an air filter – the engine could be da-
maged.
Only original spare parts may be used in the course of maintenance.
The only exception are standardised parts (such as ball bearing,
screws, nuts, etc.) which match the specifics of the original part.
1.9. Disposal of toxic waste
The incorrect disposal of toxic waste poses a threat to the environment
and is prohibited by law. Hazardous wastes include: lubricants, fuels,
filters and batteries.
Collect poisonous liquids in suitable sealed containers.

5DE
2. Transportation and storage
2.1 Transportation for assembly
Incorrect handling can cause serious damage to the device!
You can pick up the device using the motor base plate (using noo-
ses) and move it.
Pay attention that the lifting point is not located in the centre of the
device.
Persons have to keep a safety distance during lifting operation.
Make sure that the lifting gear and the supporting construction is sui-
ted to carry the weight of the device.
Please also consider following points:
• All used lifting means must be in good order.
• The loading capacity must be suited to the weight of the load.
• Wrong movements can cause personal injury or serious dama-
ge to the device.
• Make sure nobody is in the vicinity of the hanging motor.
• When picking up the device vertically it is important to position
the lifting point exactly into the focal point. Additionally guide
rope should be used.
• It is forbidden to pick up the device outside in unsafe weather
conditions (i.e. strong wind, storms).
• Always put down the engine carefully onto an even surface that
suits the weight of the device.
2.2. Storage as new device
• If the device is not used instantly, the engine has to be stored
at a safe, clean, dry and vibration free location.
• If gasoline or motor oil were already filled into the motor, drain
them and clean the fuel tank if necessary.
• Should there be a starter battery included in your order (which
is not the default), please consider following points:
Make sure to disconnect the minus (-) pole first and the plus (+) pole
second. During assembly the plus (+) pole is connected first, the minus
(-) pole second.
When storing batteries without battery loader make sure the tempe-
rature of your storage room is at 20°c. Do not forget to charge the
battery every 3 months. The self-drain can significantly shorten your
battery's lifespan.
• The ball bearings does not have to be cared for when the de-
vice is in storage.
2.3. Storage after the device has been used
2.3.1. Downtime for up to 2 weeks
There are no specific precautions necessary for a downtime up to
2 weeks.
2.3.2. Downtime for up to 3 months
It is recommended to drain the float chamber or to use a suitable
gasoline replacement - see the explanation under 2.3.3.
Alternatively the fuel cock can be closed during the last usage. Let the
motor run until it stalls. Note whether this is possible/desirable with
the load attached to the motor.
2.3.3. Downtime for up to 6 months
• Clean the outside of the engine.
• Drain the float chamber or use a suitable gasoline replacement.
• Drain the fuel tank and clean it or use a suitable gasoline repla-
cement.
Gasoline is only durable for a certain amount of time. The flammable
substances evaporate quickly and the fuel might not be fit to be used.
That is why the carburator must be emptied by running the engine with
closed fuel-cock until it stalls or by draining the float chamber of the
carburator. The fuel tank must be drained as well. If you wish to do
so you can use also a special kind of gasoline replacement which is
storable for longer periods (e.g. ASPEN®, HUSQVARNA XP, ...)
2.3.4. Downtime for more than 6 months
• Do the earlier service instructed by the motor operation hour
maintenance chart (e.g. after 120 operation hours the 200 hour
service should be executed).
• Start the engine and let it get to operating temperature (about
5 minutes of running the engine).
• Stop the motor.
• Drain the lubricating oil using the drain plug.
• Drain carburator and fuel tank, clean the tank if necessary.
• Maybe disconnect the battery and take it out of the device. If
available, connect it to a battery loader.
Consider during disassembly the minus (-) pole is disconnected first
and the plus (+) pole second. During assembly the plus (+) pole is
connected first, the minus (-) pole second.
When storing batteries without battery loader make sure that the tem-
perature of your storage room is at +20°c. Do not forget to charge the
battery every 3 months. The self-drain can significantly shorten your
battery's lifespan.
• Clean the device and conserve it with oil mist.
• Keep the device as dry as possible. If this is not an option
remove air filter, exhaust pipe, starter and dynamo must be
protected from moisture (either by disassembling them or by
wrapping the device in shrinking foil).
To put the device back into operation follow the instructions for the
initial start-up.

DE6
3. Specification
3.1. Technical data
B
W
H
G5
B1
T
T1 T2
G1 G2G2
G3
G4 G2
Model EG4-0210-5 EG4-0270-5 EG4-0420-5
Build type 1-cylinder 4-stroke air-cooled gasoline engine with carburator
Displacement 212 ccm 270 ccm 419 ccm
Bore x Stroke 70 x 55 mm 77 x 58 mm 90 x 66 mm
Compression 8,8 (±0,2) : 1 8,2 (±0,2) : 1 8,2 (±0,2) : 1
Maximum power 1) 4,3 kW @ 3.800 min-1 6,3 kW @ 3.800 min-1 8,2 kW @ 3.800 min-1
Rated power 1) 4,0 kW @ 3.600 min-1 5,8 kW @ 3.600 min-1 7,6 kW @ 3.600 min-1
Maximum Torque 1) 12 Nm @ 2.500 min-1 16,8 Nm @ 2.500 min-1 25 Nm @ 2.500 min-1
Idle speed 1.800 min-1 (±400)
Type of output using crankshaft
Rotation direction anticlockwise (see schematic picture)
Fuel Unleaded Standard-(ROZ91) /Super-(ROZ95) gasoline (Benzin)
or special gasoline replacement (e.g. ASPEN®, HUSQVARNA XP, ...)
Tankinhalt 3,7 l 6,0 l 6,5 l
Tank capacity ≥ 362 g/kWh
(~1,9l/h under full load)
≥ 352 g/kWh
(~2,6l/h under full load)
≥ 350 g/kWh
(~3,3l/h under full load)
Speed regulation integrated centrifugal governor acting directly onto the reducing damper of the carburator
Cooling system Forced air cooling system using a fan wheel and air vents
Lubrication system Splash lubrication system
Oil volume ~ 0,6 l ~ 1,1 l ~ 1,1 l
Max. allowed tilt during operation ±15° in all directions
Max. Inlet Underpressure 2,0 kPa @ full load, 3.800 min-1
Max. Outlet backpressure 10,0 kPa @ full load, 3.800 min-1
Complies with emission class EU Stage-V, Category: NRS-vi-1a (non road engine)
Start system
depends on version:
-H: only Recoil-starter
-HE: combined recoil- and electric starter
Dynamo
only in version "HE" (= with electric starter):
Dynamo for diode (included in startbox) and inherent charging current limitation.
100-400mA (max. 500mA) charging current - speed dependent
Battery only in version "HE" (= with electric starter) - not included:
12 V / min. 9 Ah, recomended 12 Ah
Overal width B 400 mm 430 mm 455 mm
Cylinder Overhang B1 140 mm 165 mm 180 mm
Engine depth T 248 mm 380 mm 415 mm
Depth Overhang T1 T2 95 mm 24 mm 95 mm 28 mm 102 mm 37 mm
Overal Height H 370 mm 410 mm 440 mm
Height of shaft W 106 mm 133,5 mm 133,5 mm
Baseplate
G1 G2 162 mm 11 mm 197 mm 12,5 mm 196 mm 12 mm
G3 G4 70 mm 75 mm 106 mm 82 mm 106 mm 86 mm
G5 104 mm 133 mm 144 mm
Net weight H-Version / HE-Version 15,7 kg / 17 kg 25 kg / 27 kg 31,8 kg / 34,5 kg
Sound level LWA 88 dB(A) / 67 dB @ 7m LWA 91 dB(A) / 70 dB bei 7m LWA 96 dB(A) / 73 dB @ 7m
1) Engine power data
All given information applies to the engine at 0m sea-level and a surrounding temperature of +20°c. The total capacity of the device must be
reduced because of cooling issues when using the device in higher temperatures or in greater heights - see the derating chart for details. This
also applies to the performance curves in 3.2.

7DE
3.2. Performance curves
2.000 2.500 3.000 3.600 r [ min-1 ]
P [ kW ]
7
6
5
4
3
2
18
17
16
15
450
400
350
300
Me [ Nm ]
ge [ g/kWh ]
P
ge
Me
2.000 2.500 3.000 3.600 r [ min-1 ]
P [ kW ]
5,0
4,5
4,0
3,5
3,0
2,5
2,0
13
11
9
500
450
400
350
Me [ Nm ]
ge [ g/kWh ]
P
ge
Me
EG4-0210-5 EG4-0270-5
P: Power, Me: Torque, ge: Consumption P: Power, Me: Torque, ge: Consumption
2.000 2.500 3.000 3.600 r [ min-1 ]
P [ kW ]
9
8
7
6
5
4
3
28
25
26
25
450
400
350
300
Me [ Nm ]
ge [ g/kWh ]
P
ge
Me
EG4-0420-5 P: Power, Me: Torque, ge: Consumption

DE8
3.3. Flange and shaft measurements
EG4-0210-5
EG4-0270-5
EG4-0420-5
CRANKSHAFT-OPTION: Q1 [ 3/4“(19,05)x61,7 ] CRANKSHAFT-OPTION: S1 [ KW20x53 ]
CRANKSHAFT-OPTION: S2 [ KW25x88,2 ]
CRANKSHAFT-OPTION: S1 [ KW25x63 ] CRANKSHAFT-OPTION: S2 [ KW25x88,5 ]
CRANKSHAFT-OPTION: Q1 [ KW1“(25,4)x88,5 ] CRANKSHAFT-OPTION: V2 [ TP26x77,5 ]
CRANKSHAFT-OPTION: V1 [ TP19x72 ]
M8x1.25-6H
23 3,0
53
Ø20- 0,020
-
0,053
5+ 0,03
0
17 0
-
0,10
35
65
± 0,05
65
±
0,05
4-M8x1,25
Ø41,25
+ 0,039
0
5/16-24UNF
17 3,2
61,7
Ø19,05
Ø3/4“
0
-
0,025
4,78 0
-
0,1
16,36 0
-
0,10
45,5 Key 3/16“x3/16“
M8x1.25-6H
23 16
88,2
Ø25- 0,020
-
0,040
6+ 0,03
0
21 0
-
0,10
56
117
58,5 71,5
30°
45°
Ø165,1
Ø146,08
0
-
0,04
Ø127±0,05
82,6
4-M10x1,25
4-M8x1,25
M8x1.25-6H
23 16,3
88,5
Ø25+ 0,020
-
0,041
6+ 0,03
0
21 0
-
0,10
56
3/8“-24UNF
28 16,3
88,5
Ø25,4
Ø1“
0
-
0,025
6,3+ 0,05
0
21,82 0
-
0,13
56
M8x1.25-6H
28 3
63
Ø25- 0,020
-
0,053
7+ 0,03
0
21 0
-
0,10
42
CRANKSHAFT-OPTION: S1 [ KW25x63 ]
M8x1.25-6H
28 3
63
Ø25- 0,020
-
0,053
7+ 0,03
0
21 0
-
0,10
42
Ø30
M10x1,25-6H
30
4
35
77,5
1:5
Ø26 0
-
0,025
CRANKSHAFT-OPTION: V3 [ TP26x47 ]
Ø30
M10x1,25-6H
30
4
17,5
47
1:5
Ø25+ 0,003
0
Ø26 0
-
0,025
CRANKSHAFT-OPTION: V5 [ TP25x54,5 ]
26
36
1:5
54,5
Ø23
Ø25- 0,020
-
0,072
M8x1.25 (Deep 23)
14,3 3
52,3
1:5,3333
5/16-24UNF
Deep 20
72
Ø19,843 0
-
0,025
Ø19,177 0
-
0,025
45°
30°
30°
45°
8-M8x1.25
Deep 18
Ø165.1
Ø146.08
0
- 0.04
Ø113±0,05

9DE
4. Installation
The installation has to be done by professionals. Poor installation can
damage the device (ex. bearing failure because of inadequate paralle-
lism). The professionals present are responsible for the observance of
appropriate regulations and standards.
All operations on the device including maintenance and start-up must
be done on a resting engine.
4.1. Preparation
• All devices are packed in a different way, depending on sales
channel and method of transportation. Remove all packaging
carefully, to avoid damaging the device.
Before installation, make sure that any protective coats, covers for
transport (ex. shaft cover) or other protective means were removed.
4.2. State of installation site
• The installation site must be well ventilated with dry, clean,
conditioned or ambient air, because the motor radiates heat
that would raise the room temperature so high, it would have
negative effects on the motor capacity.
• The installation site should be chosen so that normal mainte-
nance is easily possible.
• The ground underneath the must be able to take the weight of
the device. It should also be even and nonslip.
• The installation site must be designed so that accidental tou-
ching with the engine case, rotating or otherwise dangerous
parts is impossible.
• The installation site must be protected from any natural forces
(such as rain, snow, hail, storms, flooding, direct sun radiation,
frost or heat) as well as air pollutants (such as abrasive dust,
electric smog, fluff, smoke, oil, mist, exhaust gases or other
pollutants).
• Consider the noise limits at the installation site.
4.2.1. In- and outtake Ventilation
Normally, the engine can draw enough air from its surroundings.
However, the motor radiates heat that in closed spaces would raise
the room temperature so high it would have negative effects on the
motor capacity.
The ventilation plan must consider following aspects:
• diverting heat produced by the engine
• necessary air rate:
for the engine to consume properly
to cool any other devices
If the surrounding air is not suited due to dust, pollution or heat, an
additional air vent must be installed.
If the engine is to be built into an enclosed space, the air vents must
be large enough to make free air circulation possible. A guide value for
non-forced air ventilation is 0.4m².
When installing for continuous operation or in places where the instal-
lation site is very hot, it is recommended to install an exhaust fan with
appropriate volume.
To reach the highest capacity possible, the surrounding air must not
rise above +25°C. In case of higher temperatures it is necessary to
derate the power of the engine capacity.
Make sure that hot exhaust gas is not sucked in again by the engine
4.3. Motor mounting
The motor assembly must be done through four montage holes in the
base plate. A mechanical assembly using the motor flange is not al-
lowed.
Please also consider following points:
• The installation frame or foundation must be adequately di-
mensioned and torsion-resistant. It has to be robust enough to
absorb vibrations and to maintain alignment.
• The foundation must be chosen so that all mounting feet are
laid out evenly on the ground to avoid tension (possibly use
underpinning).
• Make sure the dimensions of the attachment screws are appro-
priate.
In order to achieve a large enough surface area, use a large washer
between the base plate and the mounting nut.
The engine plus any add-on device should be well balanced and
attached onto a hard metal structure with vibration damper in bet-
ween. This reduces vibration.
4.4. Exhaust gas system
4.4.1. Mounting the muffler
The muffler contained in the order is made to be used in industrial are-
as. If the engine is to be used uptown it might be necessary to replace
it with a better one.
4.4.2. Information about other exhaust gas systems
When installing a different exhaust gas system please consider fol-
lowing points:
The exhaust back pressure has a significant effect on the engines pow-
er. Too high exhaust back pressure causes lower power, hotter exhaust
gas and a hotter motor, and high consumption of fuel. The exhaust
back pressure can be held to a minimum when the exhaust system is
well dimensioned.
• Make sure that during the installation of the exhaust pipes the
radiated heat cannot be sucked in by the motor. The pipes
should be insulated. If the exhaust pipe go through walls, insu-
lation is mandatory.
• The exhaust pipe should be kept as short as possible and have
no bends. If this is not possible the radius of the curvature
should be held as wide as possible.
• When using exhaust pipes up to 10 meters in length the radius
of the pipes has to be about 30% higher than the diameter of
the exhaust manifold or the muffler exhaust pipe. The diameter
must not be smaller than that.
• If the exhaust pipe has a significantly larger radius than the
device connection, a cone-shaped connector with an angle
less than 30° should be installed additionally in order to avoid
exhaust back pressure.
• The installed exhaust pipe has to be complete and 100% leak-
proof in order to avoid heat, poisonous gases and power lost.
• It is recommended to install a screw at the lowest point of the
exhaust pipe to drain the condensate.
• Between the outtake manifold of the motor/muffler and the
exhaust pipe a flexible pipe should be installed in order to avo-
id vibration transmit and to enable thermal expansion of the
pipes.
• Make sure that muffler and any exhaust pipes are free from
flammable material (fire hazard).
4.5. Fuel System
The fuel system of the motor must provide a clean and continuous
fuel supply. Pay attention to the following points during the installa-
tion of an additional fuel tank:
• Only use gasoline durable tubes with wire netting.
• Tank ventilation is necessary in order to avoid too high or too
low pressure in the tank.
• Avoid too high pressure in the integrated tank. This can happen
when the tank ventilation is clogged up or the overrun is con-
nected to another external tank.
• Fuel tubes to and from the tank must have at least the same
diameter as their counterparts on the motor. When the pipes
are very long or the surrounding air cool, the diameter of the
pipes has to be wider to let through enough fuel.

DE10
4.6. Coupling
Before the motor can be connected to a load their compatibility
needs to be checked!
It is important to check
• whether motor and load are compatible in oscillation
• whether the measurements of shaft and flange of the motor
are compatible with the measurements of the coupling.
Motor and load have to be levelled carefully! An incorrect levelling can
lead to vibrations and bearing failure.
When starting up the motor BEFORE the montage of a coupling or a
pulley the key has to be fixed to the nut very tightly!
Make sure that while assembling a coupling or a pulley all safety mea-
sures concerning touching rotational parts are obeyed. Consider the
appropriate installation instructions from the manufacturer.
In no case whatsoever should pressure, hits or blows hit the shaft (for
example with a hammer). This could damage the bearings.
Assembly and disassembly has to be done with suitable attachment
and detachment tools!
4.6.1. Maximum axial and radial load
Make sure that the maximum axial and radial load of the motor main
bearing aren’t exceeded before operating. If you’re using pulleys it
is necessary to recalculate the life-span of both shaft bearings and
to adjust maintenance intervals accordingly.!
4.6.2. Balancing
The crankshaft of the engine is dynamically balanced with half the
key. Each element of the coupling also has to be balanced out ac-
cordingly.
When the coupling is too short the overhanging key part has to be
worked off until it is the diameter of the shaft or covered up with
rings using the key nut in the according size. If the coupling is too long
the missing key part has to be filled out in the overhanging coupling.

4.6.3. Direct coupling
When directly attaching a moving element (ex. pump, ventilator) to the
motor shaft, balance is extremely important!
The coupling has to be chosen so that the transferred torque, the run-
ning characteristics of the engine and the necessary safety characte-
ristics are considered.
The motor plus the load should be balanced out so that out-of-rounds
and deviations in balance of the two coupling halves comply with the
tolerance of the manufacturer. Sloppy balancing can lead to vibrations,
bearing failure or to the shaft breaking.
Instructions:
• Attach both coupling halves so that a movement is possible
with both halves.
• Set up the parallelism of both shafts with a comparator or a
thickness gauge at four points which are located 90° from each
other (the distance set up equals the value A).
• Measure the distance between the two contact-areas of the
coupling at four different points which are also set 90° from
each other.
• The difference between the two values may not be greater than
0.05mm.
A
A A
A
A
A
You can use two measure-devices to set up parallelism and coaxal at
the same time. While turning the shaft slowly deviations can be mea-
sured precisely.
Alignment errors are corrected by using washers between the base
and the foundation. After refastening the nuts the alignment has to be
checked again.
If you are using 2-part couplings you have to make sure to leave a
distance of 1-2mm to the shaft in order to allow thermal expansion
of both shafts.
4.6.4. Operating with a pulley
The axis of the motor shaft must be parallel to the axis of the moving
device, in order to minimize the axial force on the bearing. Make sure
the pulleys are set up in one line (see diagram below).
Assembly with a fixed axle distance:
• Attach an additional tension roller to the belt. The tension roller
should be placed on the inside of the V-belt. In case a flat belt
is used - the roller can also be placed on the outside of the belt.
Assembly with variable axle distance:
• Attach two clamping rails to the base. They must be parallel to
the belt.
• Attach the load (not the motor) as shown in the diagram below.
This way everything can be balanced out as precisely as possi-
ble.
Tension screw
Tension screw
The tension of the belt has to be set up very precisely. If the tension
is too high the shaft bearing wears out very fast and the crankcase
or the shaft might break. If the tension is too low, vibration can oc-
cur, which can also damage the device.
Starting at a pulley diameter of 315mm and a rotational speed of
3.000min-1 we do not recommend using pulleys made from gray cast
iron or using flat belts.
Please note that all moving (rotating) parts must be protected from
touching anything before starting up the device!

11DE
4.7. Concluding mechanical installation instructions
After the first start-up the correct alignment is to be checked while the
motor is as warm as it usually is while operating..
• All screws, nuts and other clamped or bolted connections
must be correctly assembled and fastened.
• The cooling air must be able to circulate without a problem.
4.8. Mounting the oil-sensor controller
If the optional available oil sensor controller (Order Nr. ZSP-
MOT00442) be included, assemble it as follows:
• Open the plug connection (A) between the float switch and the
main switch (ignition breaker), as well as the plug connection
(B) between main switch and ignition coil connector.
B
cable attached to ignition coil
cable attached to ignition coil
Oil float sensor
Oil sensor
controller Oil float sensor
OFF
O
N
A
F
OFF
O
N
E D
• Mount the oil sensor controller on the crankcase.
• Connect:
- Oil-sensor-controller and Oil-float-sensor (D)
- Oil-sensor-controller and Main switch (E)
- Main-switch and cable to ignition coil (F)
➽ How the oil sensor controller works:
By default the motor is equipped with a oil float sensor (=switch sen-
sor). When the oil level is too low, the float switch stops the motor. If
the float switch only triggers shortly the switch is not guaranteed to
successfully stop the engine. The oil sensor controller also stops the
motor when the oil level is only briefly too low.
4.9. Electrical Assembly (only for “E” version)
ATTENTION - By default engines in version "E" are delivered WITHOUT
stop-switch! The wiring MUST be adapted to one of the following.
Otherwise the running engine cannot be stopped.
Depending on the version the engine is equipped with following
electrical components:
➽Version "H" (means only Hand-start version):
No further electrical components
➽Version "E" (means with additional Electric-start):
Dynamo (without necessary diode) and electric starter.
ATTENTION: no stop-switch preinstalled!
➽Special components (additionally available):
- Startbox (with rectifier diode and main-switch)
- Battery
4.9.1. Electrical connection (chords)
Only use stranded wire cable as a connection.
Battery(+) as well as battery(-) chords are to be held as short as
because the current of the starter is very high.
Note that the motor and add-on-parts get hot when used. Always
protect the cable from touching hot parts by using a protective hose.
Caused by motor vibration during operation all screw connections
must be secured with spring washers or lock-nuts.
4.9.2. Starter battery
A starter battery and a battery cable are not included in the delivery,
they can however be ordered separately as add-ons. Make note of
following points:
Lead acid batteries contain sulfuric acid. If there are liquids
escaping from the battery, do not touch or swallow them.
Carefully dilate the acid with water and neutralize it with soda
(sodium carbonate).
Always wear protective gloves and safety goggles when wor-
king with the starter battery.
• You can find the necessary capacities in the chart in chapter
3.1. The usage of valve-regulated (maintenance free) batteries
is recommended.
• Always connect the plus(+) pole first, then the minus(-) pole.
Fasten the connections properly.
4.9.3. Mounting of optional Startbox
The optionally available starter box (with rectifier diode and main-
switch) is to be assembled as follows:
• Open all plug connections and assemble the starter box (see
pictures in 5.1.)
STARTBOX
Starter motor
Battery
Oil sensor
controller
CN30
CN11
CN10
CN2
CN3
CN6
GND
Crankcase
cable from dynamo
cable to
ignition coil
Oil sensor
• Mount a cable lug on both battery cables.
• Mount battery(-) cable as well as CN30 (yellow/green marked
cable with M6 cable lug) with any screw on the crankcase
(crankcase is allways ground/GND/0V).
• Connect CN2 (yellow marked cable with M4 cable lug) to oil-
sensor-controller (if no oil-sensor-controller is equipped con-
nect the cable with oil-sensor).
• Connect CN3 (black marked cable with M4 cable lug) to igniti-
on coil.
• Connect CN6 (brown marked cable with M4 cable lug) to dyna-
mo.
• Connect CN11 (black/white marked cable in heat protection
tube with 6,35mm Faston lug) to relais of starter motor.
• Connect battery(+) cable with M6 cable lug to starter motor.
Connect CN10 (white marked cable in heat protection tube
with M6 cable lug) also to the same port of the starter motor.
• Secure all cables with the cable fixer und connect the battery
cables to the batteries - see notes under 4.9.2.

DE12
5. Usage
5.1. Illustration
(Model EG4-0420 in version "E" is showed below)
Oil gauge Carburator
Muffler
Muffler
Oil gauge
Oil gauge
Recoil start
Air filter
Air filter assy.
Engine vent
(cooling)
AC-output
of dynamo
(only "E"-version)
Tank cap
Tank cap
Starter motor
Tank
Tank
Starter relais
Oil filling port
Oil filling port
Oil filling port
Cylinder head
valve cover
Oil drain screw
Engine flange
Crankshaft
drain screw
Mounting screw
(Loose to dismount float chamber case)
float chamber
Idle speed setting
Oil drain screw
Adjusting speed for max. rotation/speed
Throttle
Choke
Fuel Cock
Fast
START
OFF
Slow
OPERATION
ON

13DE
5.2. Information about engine performance
The performance refer to standard conditions (0m sea level, +25°C
ambient temperature). For higher temperature or usage at higher sea
level it is necessary to calculate a derating of the maximum perfor-
mance.
5.3. Information about starter battery (optional)
Please consider following points:
Lead acid batteries contain sulfuric acid. If there are liquids escaping
from the battery do not touch or swallow them. Carefully dilate the acid
with water and neutralize it with soda (sodium carbonate).
Always wear protective gloves and safety goggles when working with
the starter battery.
When correctly set up, the battery will be charged via the built in dy-
namo.
If the motor is operated without a battery (ex. when using an external
battery to start up), the plus cable from loading regulator has to be
isolated against the crankcase. A shortcut could damage the dynamo
or loading regulator.
When using a car battery to jump start the engine, first disconnect the
starter battery of the motor. If the built in battery is completely drained
the car battery could load an extremely large current into the starter
battery. This seriously damages the battery, in extreme cases the bat-
tery might even explode.
Be very attentive when handling starter cables, if it comes to an elec-
trical shortcut very large currents can be transmitted. Therefore re-
member: always connect the plus(+) pole first, then the minus(-) pole.
5.4. Check-ups before every start-up
5.4.1. Engine oil
Oil is the most important resource of the motor. Only use high qua-
lity, synthetic motor oil of specification API SL/SM, for gasoline en-
gines.
Check the oil level bevor every start up! ATTENTION – when delivered
the engine is NOT supplied with oil and must not be started up under
any circumstance!!
Remove the oil dipstick ❶and wipe it
with a clean piece of cloth. Reinsert the
clean dipstick ❶completely, then re-
move it again. The correct oil level ❸is
now marked by the oil film covering the
dipstick. The line has to be close to the
maximum mark ❹. If necessary add more
oil, in order to achieve the correct oil level
❷(lower edge of the thread in the crank-
case).
Do not add too much oil – too much oil is damaging and must be drai-
ned! Different types of oils and brands may not be mixed together!
Note the maintenance intervals of the oil change.
5.4.2. Fuel
Fill up the tank completely with fresh, lead-free premium or normal
gasoline.
Please note that gasoline usually should not be stored for longer than
3-6 months. Always use fresh gasoline. See the instructions for storage
in chapter 2.3. For further information.
5.4.3. Other check-ups
• Remove any dirt or dust, so that the engine cooling cannot
suck in any foreign matter.
Note that the motor must NOT be started up if the protective covers are
not attached properly.
• Check that the device does not have any leaks (fuel, oil, battery
acid). Fasten leaking sealing caps appropriately.
• Make sure the device is well ventilated. The exhaust gas of the
motor can be damage your personal health.
5.5. Start-up
5.5.1 Special information about initial start-up
The motor must only be started up when the device was installed fol-
lowing the rules and instructions of this manual and the engine base is
fixed properly to a stable mounting frame.
• Let the motor run on half rated rotational speed (aprox. 1.500-
1.800 min-1) for 1 hour after starting up for the first time.
• Turn off the engine after initial start-up and check the oil level.
• Check all screws, nuts and clamp connections after initial
start-up. Refasten if necessary.
If the engine behaves abnormally (noise, smoke) turn off the motor
immediately and solve the cause of error before putting the engine
into operation again.
To ensure a maximum life-span of the motor it is recommended not
to operate above 3.000 min-1 in the first 50 hours of operation. Only
change the speed slowly during this 50 hours (change governor po-
sition slowely)!
5.5.2. Starting the engine
It is forbidden to start up the motor without properly assembled air
filter and muffler!
• Open the fuel cock
• Shift the choke lever to “Start”
• Move the throttle lever to full-speed (=Start)
5.5.2.1. Hand start (all versions)
• Pull the recoil-starter slowly until you feel some resistance.
Bring the recoil handle slowly back.
• Pull the recoil handle hard and fast.
• Repeat until the motor starts up.
?
5.5.2.2. Electric start (only motor version “E”)
• Turn the start key to “START”. Let go of the key as soon as the
motor starts up.
Only start up for a maximum of 10 seconds! If the engine doesn’t start,
wait one minute until trying to start-up again. This process may only
be repeated for a maximum of 3 times, then the electric starter has to
be left to cool down for at least 15 minutes. Contravening can result in
damaging the starter and/or motor. Never start into the running engine!
Generally you should not connect a load higher than 50% of the nomi-
nal load when the engine is cold.
• Observe the engine run and the colour of the exhaust gas after
starting up. The engine should run smoothly after a few se-
conds.
• Slowely bring back the chocke lever to position
"RUN"/"BETRIEB"
5.5.3 Stopping the engine
• Let the engine run without load for about five minutes after
being used for heavy load – this way the motor can cool down.
• Bring stop-switch or main-switch to position "OFF" to turn off
the engine.
• Close the fuel cock.
When the device is not to be used for longer than two weeks, consider
the instructions in chapter 2.3.

DE14
6. Maintenance
Regular service and maintenance prolongs the life-span of your de-
vice and enables an undisturbed user experience.
The staff responsible for maintaining and cleaning the device must
be trained to do so. Never let unable people handle the device in any
way at all.
6.1. Instructions about maintenance
If you hire a specialised company to maintain the device, please get
a conformation from them.
Any damage done to the device due to inappropriate maintenance or
not maintaining the device at all do not carry warranty.
Fixing issues that can be fixed by the user himself do not carry war-
ranty either but fall into the normal maintenance of this device.
6.2. Precautions
Before cleaning, oiling or servicing the device follow these instruc-
tions:
• Turn off the motor. The motor must be at rest.
• Use appropriate measures to keep the motor from starting up
again.
• The motor and all of its add-on parts must have cooled down
to the surrounding temperature.
Pay attention while working in close proximity to moving parts and
parts that might be hot.
6.3. Starter battery
If you are using a battery that needs to be maintained, make sure
to regularly check the state of the connectors and the water level. If
necessary fill distilled water up to the maximum mark.
After a long storage period the loading condition of the battery must
be checked before putting the device into operation. Weak batteries
must not be used.
6.4. Cleaning the crankcase
Clean the engine block from the outside with compressed-air or with
suitable detergents.
Electric parts (clamps, electric starter, etc.) must not be cleaned with
compressed-air or any liquid cleaners. This could lead to a short or
other disruptions.
It is extremely important to have free air ventilation in order to cool
the motor down. Therefore you must clean the bars and ribs of the air
vents immediately, even if they’re only slightly dirty.
6.5 Upkeep
Engines are technologically complex mechanisms with many mo-
ving parts. There parts are subjected to strong mechanical, thermal
and chemical forces because of the environment and the combusti-
on process. Choosing the correct fuel and oil as well as thoroughly
servicing and maintaining the device significantly prolongs the life-
span of your device. Small mistakes can cause huge problems –
even break the device entirely.
Here you will find instructions how to properly identify and maybe
even correct some disruptions. However, some difficulties can only
be handled by trained staff or professionals. If you have a problem
go over this list point by point – often the problem is small and easily
solved.
A gasoline engine needs 5 things to work:
➽OIL ➽IGNITION ➽GASOLINE ➽AIR ➽CORRECT TIMING
You should check in this order to find the cause of a possible pro-
blem.
6.5.1 Changing the engine oil
Always check the oil level before starting up! There are marks on the
dipstick marking the minimum and maximum – when the device is
set up on an even surface the oil level should be between these two
marks.
Do not overfill! Too much oil can cause damage and must be drained.
Oil is the most important resource of the motor. Stick to the mainte-
nance intervals and its schedule!
Put a suitable container under the drain screw, open the drain-screw
and drain the motor oil. Always change the motor oil while it is warm!
Normally, the oil should be black because of the combustion residue
of the motor. There should be no foreign substances, white colouring
(water in the oil) or foaming visible.
The spent oil taken from the motor has to be brought to a collecting
point for toxic waste!
Close the drain screw after draining.
Fill new oil into the motor, make sure to use the correct one (see
5.4.1.).
After changing the oil, start up the engine and let it run for 5 minutes.
Then check the oil filter and the drain-screw for any leaks. Check the
oil level again and refill oil if necessary.
If the oil level increased from one check to the other do NOT start the
machine. Fuel or water might have gotten into the motor oil – this can
damage your device. In those cases drain the oil completely and try to
identify pollutants such as water or fuel (check the smell, maybe try
to set small amounts on fire, see whether water separates from the
oil). Find out why there is leakage into your oil and fix it. Wash out the
crankcase with fresh oil and change the oil.
6.5.2. Check the ignition (spark)
Pull the spark plug connector from the spark plug. Remove the
spark plug using a spark plug socket.
• Inspect the state of the electrodes as well as the distance bet-
ween the electrodes according to the chart below. The spark
plug should be coloured somewhere in between grayish-white
and yellowish-gray. There should be no residue such as carbon
or soot visible.
• Clean the spark plug with a delicate wire brush and establish
the suitable distance between the electrodes (this works best
by gently tapping the diodes with the back of the wire brush).
The colour of the residue (the appearance of the spark plug) is very
informative about the state of the motor. Check the appearance accor-
ding to the following diagrams to find the cause of a problem.
If necessary replace the spark plug according to the type mentioned
in the chart.
• Place the spark plug into the spark plug connector and hold the
ground electrode against the crankcase while the ignition is on.
• Turn on the main switch (ignition break, ignition lock) and
quickly pull the hand start. There should be sparks visible bet-
ween the electrodes of the spark plug. If there are no sparks
visible also exchange the spark plug and repeat the process.

15DE
6.5.2.1. Spark plug chart
Technical data EG4-0210
EG4-0420
Thread M14x1.5
Length 19,0 mm
Electrode distance 0,7 mm
Manufacturer
BONON F7TC
F6RTS
BOSCH W7DC
CHAMPION N9YC
NGK BPR6ES
6.5.2.2. Appearance of the spark plugs
Normal state
This spark plug is in good state. The insulator is gray-
ish-white to yellowish-gray. The plug is working under
optimal temperatures. Here the heating value, the igni-
tion and the alloy are well adjusted, the electrodes are
not worn, they only have little residue and the electro-
des have the perfect distance.
In the past the ideal colour of the spark plugs
was to be brownish-red. This goes back to
the time when lead was added to the gasoli-
ne and is not the case nowadays.
Worn electrodes
In this picture you see extreme burn-off of the elect-
rodes. This leads to bad correspondence with the mo-
tor, as well as problems starting up. Although there is
barely any residue and the plug has the right colour
you will have to replace it. Actually, it would have been
necessary long ago! Use a spark plug with the same
heating value as the previous one, which corresponds
to the specification in this manual.
Soot residue
In this picture you see sooty residue. This is not dange-
rous, indicating a too heavy fuel air alloy. This residue
is particularly prominent when the motor is used with a
light load. After a few minutes of using the motor with
its maximum load the residue should pass. If it does
not the heat-value of the spark-plug is incorrect (wrong
spark plug). Also, the air filter could be dirty or clogged,
the valves lose or the choke not fully deactivated.
Spilt/glass-like residue
Small dashes of residue indicate that there is dirt in the
intake, which is sucked in and melts. The problem is
solved by cleaning the carburetor and replacing the air
filter. A yellowish, glass-like shiny glaze accumulates
on the tip of the insulator from gasoline or motor oil
residue and melt during maximum load. The resulting
problems with ignition should be avoided during pro-
longed use with lower power.
Combustion residue
These light brown crusts on the electrode and the in-
sulator are caused by residue from gasoline and mo-
tor oil. The spark plug does not work properly and the
combustion gets worse. Often larger amounts of oil get
into the combustion chamber, are not burnt entirely and
leave behind this residue. Check the valve guide and
valve seat and do not use gasoline additives. Changing
the brand of gasoline you are using can also help.
Bridged electrodes
In older motor cycle times, then the fuel was low in
quality, this was a common problem. The residue ac-
cumulated to a kind of bridge between the electrodes.
Two-cycle engines were particularly prone to this pro-
blem. Here cleaning the spark plug helps, as well as
using high quality fuel and oil. Of course, there might
be a more deep-seated problem such as a worn piston
or worn cylinders.
Overheating
The insulator is chalky white and there is absolutely no
residue visible. The motor got way too hot! The cause
could be a too low heating value of the spark plug or
a too light fuel air alloy. Check all of these points and
replace the spark plug with a new one according to the
chart.
Oil residue
Oily and greasy residue is an indicator of large amounts
of oil getting into the combustion chamber. The cause
of this could be a problem in the valve guide, a worn
piston, piston ring or cylinder liner. Checking the com-
pression can help find the problem. Usually this causes
a greater engine overhaul. In two-cycle engines this
state can also occur when the crank case seal fails and
gear oil is sucked in.
Gasoline residue
The plug is very similar to the one depicted above.
When removed however, the wet spots dry quickly and
only soot residue is left. This is not oil but fuel. The mo-
tor was flooded because there was too much fuel in
the combustion chamber. Here cleaning the spark plug
and opening the choke helps. If there still is a problem
check the ignition and the needle valve.
Broken insulator because of back fire
When the motor backfires hard the insulator can break
and even spall. Check whether you used gasoline with
the correct octane value. A problem in the cooling sys-
tem or an incorrect distance between the electrodes
can cause problems. Other causes are bad ignition ti-
ming (too early) or too light fuel air alloy (additional air
or valves clogged). A wrong spark plug (wrong heating
value) can cause this also.
Molten electrodes because of a
knocking engine
If the electrodes have molten, uncontrollable ignition
and very high temperatures were the cause. The wrong
heating value, overheated valves, light carburetor set-
tings, additional air, too much carbon residue and sharp
edges in the combustion chamber could be the cause.
Check all of these points and replace the spark plug
according to the chart.
Electrodes and insulator molten
If you ignore engine knocking for a longer amount of
time the electrodes and even the insulator will melt.
The wrong heating value, light carburetor settings, way
too early ignition, additional air, too much carbon resi-
due and sharp edges in the combustion chamber could
be the cause. Check all of these points and replace the
spark plug according to the chart.
Mechanical destruction
Rare, but it has happened! This spark plug was comple-
tely destroyed because it touched parts in the combus-
tion chamber.It is extremely important to find the cause
of this. Maybe the piston or the valves are broken, or
large amounts of carbon residue got loose. However,
you might have used a spark plug that was too long
and touched the valves of the piston. Check all of these
things and replace the spark plug with a new one.

DE16
6.5.2.3. Solving ignition problems
If there are still problems after exchanging the spark plug and there
is no spark, follow these instructions:
• Check the spark-plug connector for any damage or moisture
and if necessary clean or exchange it.
Disconnect connector (G) - by doing this you’re deactivating the
oil-sensor-controller. The electrical connector must not touch the
crankcase during operation. Also check the oil level, because in this
condition there is no oil-level monitoring.
If the engine is running normally now, connect (G) while the motor
is operating. If the motor is still running the oil float was stuck - the
problem was just solved because the motor oil become warm and
lossen the stucked float. If the motor stalls when (G) is connected,
open (D) and restart (let G connected). If you cannot start, the oil-
sensor-controller is broken. If you can start, the oil sensor (float
switch) is broken. The oil sensor can only be exchanged by opening
the crankcase, from the outside only the cable connection to the oil
sensor is visible.
If that is not the problem open (H) (=contact between stop-switch
and ignition coil). Try to start the motor. If the ignition is not working
the cable to the switch or the switch itself have an electrical short
against ground. Solve the problem accordingly.
If there is still a problem remove the cover of the flywheel to get to
the ignition coil:
Disconnect the Faston-connector (M) - the cable coming from the
connector (H). If the ignition is working now, the cable has an elec-
trical short between (H) and (M). If that is the case, correct the pro-
blem.
If there is a problem, measure (M) against ground (crankcase). There
should be a resistance of 1,0-1,5 Ohm. Now measure (N) (=spark
plug connector) against ground. There should be a resistance of
10-11 kOhm. Check the state of the ignition cable (no frets, brittle-
ness etc. as well as proper assembly of the spark plug connector on
the ignition cable (tight fit). If necessary exchange damaged parts.
(M) may not have any connection to ground when the ignition is
“ON”. When the stop-/main-switch is in position “OFF” there must
be an electric short against the ground.
Lastly, check the permanent magnet at the flywheel. Remove the
pollutants and set up a distance at (P) of
EG4-0090-series: 0,2-0,4 mm
EG4-0210/0270/0420-series: 0,4-0,6 mm
between ignition coil and flywheel. The ignition magnet may not
grind against the flywheel. The distance of both sides (P) has to be
identical! The timing of the ignition is fixed and cannot be changed.
6.5.2.4. Starter malfunction
If the starter is spinning during startup (if the starter turns but the
motor does not turn with it) the starter gear is probably broken. In
that case, please contact your retailer.
If the starter does not react at all during startup, please consider
following instructions:
• Check the voltage of the battery
If the voltage is above 12V, please check the connection bet-
ween minus pole of the battery and the crankcase.
• Measure the Voltage at (K) (battery plus cable=the thick cable
connected to the starter - measurements are always conduc-
ted against the crankcase). There must be battery voltage. If
there is not, the cable connection between the battery and the
starter relais is loosen or broken.
• Measure the Voltage at (J). If the main-switch is set to “OFF”
or "ON" the voltage should be 0V - if it is set to “START” there
should be battery voltage. Exchange the damaged parts.
If the measured values for (J) and (K) are within the limits, the starter
itself is probably brocken and has to be exchanged.
If the measured values are not in order, check the connectors of the
startbox. If there is no mistake - open the startbox.
• Check the 5A fuse.
• If the fuse is in proper condition, measure the voltage on the
main-switch: White cable should be battery voltage - follow the
cable wiring and check the solder points.
• If the measured values are in order, measure the voltage on
the black-white cable. At key-position "OFF" there should be
0V. At key-position "ON" and "START" there should be battery
voltage.
6.5.2.5. Battery does not charge
If the motor has started up successfully, the starter battery should
be charged by the built-in dynamo. If this is not the case, follow
these instructions:
Check the circuit breaker at the starter box and press it. If the switch
triggered or triggers again (2A pushbutton fuse), the current trans-
ferred from the dynamo to the battery is too high. Either the battery
is worn or there is any shortcut against ground.
If the circuit breaker is ON, open the connector (I) (white to brown
cable) and start the engine. Measure at running engine and opened
connection (I) the voltage on white cable against crankcase.
Measures of the dynamo: at engine speed (rpm)
1.500 2.000 3.000
Idle voltage before diode VAC 11,7 14,3 20,9
Shortcut current before diode AAC 0,57 0,58 0,59
Idle voltage after diode VDC
TRUE RMS 4,6 5,8 8,0
Shortcut current after diode AAC
TRUE RMS 0,49 0,52 0,58
The dynamo starts charging the battery at about 1000 rpm, although
the True RMS value of the direct current after the diode is only 5.8V.
The diode is now conductive at the peak-voltage point and charges
the battery.
The dynamo has a high inner resistance in order to be able to charge
the battery with little current and without charge controller while not
doing any damage to the battery by overcharging it.
D
G
H
I
J
K
M
O
P
N

17DE
If a stronger dynamo is required in order to operate side aggregates
or lights, an external dynamo has to be assembled. Either you use a
standard dynamo with a pulley or a small generator with permanent
magnets, like the ones we use in our diesel engines.
6.5.2.6. Circuit diagram - version "H"
OFF
ON
GND
M
Ignition coil
Oil sensor controller
GND
Oil sensor
GND
Spark plu
g
connector
N
yellow
Dyellow
black
H
black
10nF
10nF
10k
1k
47µF
+
MCR 100-8
GND
Stop switch
black
yellow
G
6.5.2.7. Circuit diagram - version "E"
Key (main) switch
OFF
ON
START
12V / 10 - 20Ah
M
black
J
Starter Relais
GND
M
G
GND
Ignition coil
Oil sensor controller
GND
GND
Oil sensor
GND
Spark-plug connector
N
Battery
GND
red
K
yellow
D
G
yellow
black
H
black
Dynamo
I
brown
10nF
10nF
10k
1k
47µF
+
MCR 100-8
GND
black
black
OFF
ON
START
Startbox
brown
black
black
Fuse 2A
Fuse 5A
GND
ATTENTION!
The startbox case must be
connected to the crankcase
Electrical GND connection has
to be verified!
7
8
5
9
6.5.3. Fuel Supply
During check-ups of the appearance of the spark plug you may have
noticed that the gasoline supply is too less. (spark plug is dry, al-
most no residue, insulator is white).
Check whether there is enough fuel in the tank. Look into the tank
to check for dirt, rust or, during winter, small ice crystals. If you find
any of the above drain the tank completely and fill it up with new
gasoline.
Remove the float chamber cover of the carburator and open the
fuel cock. Gasoline should run out. If this is not the case, remove
the tank and take out the filter. Wash out the filter in clean gasoline.
fuel filter

DE18
6.5.3.1. Cleaning the carburetor
Close the fuel cock and drain the gasoline using the drain-screw of
the carburator or by unsrewing the float chamber of the carburator.
Drain the gasoline into a glass container and check the drained ga-
soline for pollutants as well as water.
To clean the carburettor the air filter assembly must be removed.
Now unscrew the float chamber. Check and clean the float cham-
ber. The float must easily move up and down. The float is hollow and
must not be filled with gasoline. In that case the float is leaky - close
the hole with gasoline proof glue after removing any gasoline residue
or change the carburator.
The float triggers a needle valve. When you push the float upwards
and open the fuel cock - the gasoline may not flow on. If the float
pushed downwards the needle valve opens up and gasoline flows
into the float chamber. When the needle valve does not work pro-
perly the axis of the float can be removed and both the valve seat
and the needle should be cleaned accordingly. If the needle valve
is broken or the float has a hole, too much gasoline is released into
the float chamber.
Generally the carburetor can only be set up in very narrow borders.
The default is set by the used factory-needle. If necessary for special
usage (for example for usage at high sea level) the main nozzle must
be changed for one with a different diameter.
The adjusting screw for idle speed is responsible for mixing the alloy
during idle. The standard set-up is 2,5 turns open.
The carburetor is fixed to the device with two long screws below
the air filter case. Check that the nuts are all well-fastened in order
to avoid additional air getting into the device through the seals bet-
ween intake pipe and carburettor. If necessary, open the screws and
the seals between carburettor and intake pipe.
6.5.4. Cleaning and exchanging the air filter
If the air filter is loose or dirty the engine performance will be low (ex.
motor produces black gas under load). Therefor you must always
change the filter according to the maintenance intervals.
Open the nut on the top of the air filter box and take off the cover.
Also remove the nut from the air filter. The filter can now be taken
out of its base.
The filter element can be washed out in gasoline. Let the filter dry
completely after washing it. Check for any tears or other damage.
If the filter is damaged it must be replaced. Additionally clean the
inside of the air filter case with a dust cloth. Then place the filter
element on the base fix it with the screw and close the air filter case.
Sometimes tiny dirt particles are not visible with the naked eye. Indi-
cators for pollution are when the motor is producing black smoke (not
enough air). In that case exchange the air filter. Never put the motor
into operation without an air filter - this could damage your device.
6.5.5. Proper timing/adjusting the valves
Improper valve clearance is noticeable by restless engine run, back
fire or low performance.
To set up the valves follow these instructions:
• Remove the valve bonnet.
• Press the outtake-valve and turn the shaft manually using the
hand start until both valves are closed (valves completely out/
push rods at their lowest point).
• The push-rods should be easy to move. Check the valve clea-
rance with a feeler gauge. The valve clearance should be 0,10-
0,15 mm when the engine is cold for both valves.
Should there be no feeling gauge available normal typewriter paper is
fine (meaning two layers of paper).
• Unscrew the check nut in order to set up the valves. Set up the
valves with the adjusting-screw so that if the feeler gauge is
moved through the gap there is a noticeable resistance. Then
hold the screw until the check nut is refastened.
• Check the valve clearance again and repeat the process if ne-
cessary - check allways both valve clearance values.
When reassembling the push-rods they have to lay on appropriate ta-
pers of the camshaft (in the engine). Check whether the valves are
working properly by turning the camshaft.
The timing of this device is fixed and cannot be changed.
It has to be easy to move or turn the push rods. The valve springs must
not be broken and the push rod guides must not be worn. The position
(how deep the nut is) of the check nuts should be nearly the same.
Significant differences of nut depths are a sign of incorrect assembly
or a damaged rocker arm, push-rod or valve. In that case remove the
rocker arm entirely and pull out the pushrod. Always replace damaged
or deformed parts.
• After setting up the valves reassemble the bonnet assembly.
Check whether the bonnet gasket is properly mounted.
Drain screw
nozzle
axle of float
Mounting screw
(Open to dismount the float
chamber cover)
float chamber
needle valve
nozzle and
nozzle-holder
screw for idle speed
O-ring
float
Exhaust valve
Valve spring
Rocker arm
Push rod
Check nut
Adjusting screw
Rocker arm
Valve disc
Inlet valve
Check gap

19DE
6.5.6. Speed setting
The actual speed of the motor is set up over a mechanically adjus-
table speed governor. If there are just small deviations the rotational
speed can be set via the adjusting screw. Because the mechani-
cal regulator always has a negative deviation, adjust the rotational
speed without load to about 2-4% above the target speed. At full
load the rotational speed can be 2-4% below the set.
If the deviation is too big, try if the engine reacts on speed changes
by changing the throttle setting.
The change of the throttle mechanism has to be effortless and
should not be in idle or full-gas position. If the engine don't
react on throttle changes - stop trying to change the
speed setting. Proceed with below described proce-
dure.
Is the deviation too big, the link can be readjusted. At still standing
engine the regulation arm will be pulled to full-gas position by the
main spring.
Unhook the throttle link at the carburator (unhook bounce spring -
pull carburator throttle valve to idle position and remove the throttle
link to the top).
If you turn the carburator throttle valve to full-speed position, the
end of the throttle link should withstand 5-7mm to full-speed positi-
on (needed spare for regulation). If not you have to open the tommy
screw on the regulation arm.
Adjust the regulation arm to reach the needed spare for regulati-
on - end of throttle link must withstand 5-7mm over the full-speed
position of throttle valve. The axle of the regulation arm have to be
in position full-speed (standard arm position at still standing engine).
Fasten the tommy screw and replace throttle link and bounce spring
to the carburator. Restart the engine and adjust the speed like de-
scribed above.
If the tommy screw is too short you van also longer the main spring
by bending the ends of the spring.
The main spring has no influance to the engine speed. It prevents only
fluttering of the throttle link (the throttle link is allways under tension)
6.5.7. Governing behaviour
The mechanical governer can be influenced in its regulation in diffe-
rent ways. The governing (how much the actual speed deviates from
the ideal speed) and the oscillating (engine speed oscillates arround
ideal speed) are important. These two characteristics disagree with
each other. Optimal balance is reached when the speed changing
causes a 1-time low oscillation.
This means: set up the speed without load. Then burden the motor
up with maximum load. Now the speed must first sink, then become
higher than the rated speed and then final go back to rated speed.
Engine speed should not oscillate around the rated speed.
To improve the governing, the regulating spring as well as the bounce
spring can be hung on different positions - see schamtics under 6.5.6.
Normally a allready marked rated speed has to be reset after changing
the spring position.
Normally it is not necessary to change the speed or the behaviour. At
too low engine speed first check for any other causes of error (air filter,
fuel, valves, etc.)!
6.5.8. Muffler and colours of exhaust fumes
Backfire can be a result of loose screws on the outtake-manifold or
the muffler. In that case the fit of the screws as well as the state of
the gaskets should be checked. The exhaust pipe should be leak
and damage free
Residue must be removed from the exhaust pipe and the muffler. How-
ever, such residue indicates that either the wrong fuel is being used or
that oil is being burnt.
Too much exhaust back pressure can overheat the engine.
The colour of the exhaust gas can be an indication of the current
operation state of the motor:
motor is smoking
white or grey
water in the
fuel drain the fuel tank
motor is smoking blue motor oil is
being burned
check the oil level, valve guides,
compression and the fuel
(no 2-stroke fuel!)
motor is smoking
black
too heavy load
(too much
fuel)
check the air filter, carburator,
choker-setting and spark-plug.
Maybe reduce the load
Max. speed Limit
Main spring
Regulation arm
Faster
Regulation
Faster
Regulation
More
Stable speed
More
Stable speed
Throttle link
Bounce spring
Tommy screw
throttle valve throtle link
bounce spring
full-speed idle
Throttle lever
unhook bounce spring - push throttle valve to idle position
5-7mm spare for regulation (withstand)
5-7mm spare for regulation (withstand)

DE20
6.5.9. Other
Unusual noises might be caused by worn piston, piston-rings, cylin-
der, piston bolt, bearings, etc..
Metallic tingling is caused by the motor misfiring. Causes are resi-
due on piston/crankcase, extremely early ignition, worn spark plug,
too light alloy or bad gasoline quality.
Too little compression might be caused by worn pistons, broken
cylinders, incorrect set up or leaking valves.
Possible causes for an overheating motor are a too light alloy, a too
heavy load, badly timed ignition or a clogged up ventilation system.
If there is water in the fuel the engine does not start up, it smokes
white or it runs very restlessly. In this case drain the fuel.
6.5.10. Engine torque and measured values
EG4-0090 EG4-0210
EG4-0270 EG4-0420
Cylinder head 22-24 Nm 34 Nm 35 Nm
Pleuelstange 10-12 Nm 14 Nm 15 Nm
Flywheel 70-80 Nm 113 Nm 115 Nm
Inlet valve Opening: 10° aTDC, Closing: 20° aBDC
Outlet valve Opening: 30° bBDC, Closing: 10° bTDC
Inlet Valve
clearance 0,10-0,15 mm cold
Outlet Valve
clearance 0,10-0,15 mm cold