Robin EH36 User manual

R
Model
ISSUE EMD-ES1724
EH36/41
Air-cooled, 4-cycle Gasoline Engine

CONTENTS
Section Title Page
1. SPECIFICATIONS....................................................................................................... 1
2. PERFORMANCE ........................................................................................................ 3
2-1 MAXIMUM OUTPUT........................................................................................................ 3
2-2 CONTINUOUS RATED OUTPUT .................................................................................... 3
2-3 MAXIMUM TORQUE ....................................................................................................... 3
2-4 PERFORMANCE CURVES ............................................................................................. 4
3. FEATURES.................................................................................................................. 6
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS .......................................... 7
4-1 CYLINDER AND CRANKCASE ....................................................................................... 7
4-2 MAIN BEARING COVER ................................................................................................. 7
4-3 CRANKSHAFT.................................................................................................................7
4-4 CONNECTING ROD AND PISTON ................................................................................. 8
4-5 PISTON RINGS ...............................................................................................................8
4-6 CAMSHAFT ..................................................................................................................... 8
4-7 VALVE ARRANGEMENT ................................................................................................. 9
4-8 CYLINDER HEAD............................................................................................................ 9
4-9 GOVERNOR SYSTEM .................................................................................................... 9
4-10 COOLING SYSTEM..................................................................................................... 10
4-11 LUBRICATION SYSTEM.............................................................................................. 10
4-12 IGNITION SYSTEM ..................................................................................................... 10
4-13 CARBURETOR.............................................................................................................11
4-14 AIR CLEANER ..............................................................................................................11
4-15 BALANCER...................................................................................................................11
4-16 DECOMPRESSION SYSTEM ..................................................................................... 12
4-17 SECTIONAL VIEW OF ENGINE.................................................................................. 13
5. DISASSEMBLY AND REASSEMBLY....................................................................... 15
5-1 PREPARATIONS AND SUGGESTIONS........................................................................ 15
5-2 SPECIAL TOOLS ........................................................................................................... 15
5-3 DISASSEMBLY PROCEDURES.................................................................................... 16
5-4 REASSEMBLY PROCEDURES..................................................................................... 31
5-5 BREAK-IN OPERATION ................................................................................................ 43
6. MAGNETO ................................................................................................................ 43
6-1 FLYWHEEL MAGNETO................................................................................................. 43
6-2 BASIC THEORY ............................................................................................................ 43
6-3 WIRING DIAGRAM........................................................................................................ 45

Section Title Page
7. AUTOMATIC DECOMPRESSION SYSTEM............................................................ 46
8. CARBURETOR ........................................................................................................ 47
8-1 OPERATION AND CONSTRUCTION............................................................................47
8-2 DISASSEMBLY AND REASSEMBLY.............................................................................48
9. STARTING SYSTEM................................................................................................ 50
9-1 RECOIL STARTER ........................................................................................................50
9-2 ELECTRIC STARTER....................................................................................................54
10. TROUBLESHOOTING ........................................................................................... 56
10-1 STARTING DIFFICULTIES ..........................................................................................56
10-2 ENGINE MISFIRES .....................................................................................................57
10-3 ENGINE STOPS ..........................................................................................................57
10-4 ENGINE OVERHEATS ................................................................................................58
10-5 ENGINE KNOCKS .......................................................................................................58
10-6 ENGINE BACKFIRES THROUGH CARBURETOR.....................................................58
11. INSTALLATION ..................................................................................................... 59
11-1 INSTALLING.................................................................................................................59
11-2 VENTILATION ..............................................................................................................59
11-3 EXHAUST GAS DISCHARGE .....................................................................................59
11-4 POWER TRANSMISSION TO DRIVEN MACHINES ...................................................59
12. SERVICE DATA...................................................................................................... 60
12-1 CLEARANCE DATAAND LIMITS ................................................................................60
12-2 TORQUE SPECIFICATIONS .......................................................................................66
12-3 OIL GRADE CHART ....................................................................................................66
13. MAINTENANCE AND STORAGE.......................................................................... 67
13-1 DAILY MAINTENANCE................................................................................................67
13-2 INITIAL 20 HRS. MAINTENANCE ...............................................................................67
13-3 EVERY 50 HRS. (10 DAYS) MAINTENANCE .............................................................67
13-4 EVERY 100-200 HRS. (MONTHLY) MAINTENANCE .................................................68
13-5 EVERY 500-600 HRS. MAINTENANCE ......................................................................68
13-6 EVERY 1000 HRS. (YEARLY) MAINTENANCE..........................................................68
13-7 ENGINE STORAGE.....................................................................................................68

- 1 -
1. SPECIFICATIONS
Specifications are subject to change without notice.
MODEL EH36
EH36B EH36BS EH36D EH36DS
Type Air-Cooled, 4-Cycle, Single-Cylinder,
Horizontal P.T.O. Shaft, OHV Gasoline Engine
Bore x Stroke 89 x 65 mm (3.50 x 2.56 in.)
Piston Displacement 404 cm
3
(24.65 cu.in.)
Compression Ratio 8.3
Output Continuous 6.3 kW (8.5 HP) /1800 r.p.m. 6.3 kW (8.5 HP) /3600 r.p.m.
Max. 8.5 kW (11.5 HP) /1800 r.p.m. 8.5 kW (11.5 HP) /3600 r.p.m.
Max. Torque 54.9 N
・ m(5.60kgf ・ m)
/1250 r.p.m. 27.4 N
・ m(2.80 kgf ・ m)
/2500 r.p.m.
Direction of Rotation Counterclockwise As Viewed From P.T.O. Shaft Side
Cooling system Forced Air Cooling
Valve Arrangement Overhead Valve
Lubrication Splash Type
Lubricant Automobile Oil SAE #20, #30 or 10W-30 ; Class SE or higher
Capacity of Lubricant 1.2 liters (0.32 U.S. gal.)
Carburetor Horizontal Draft, Float Type
Fuel Automobile Unleaded Gasoline
Fuel Consumption Ratio 310 g/kW
・ h(230g/HP ・ h) At Continuous Rated Output
Fuel Feed System Gravity Type
Fuel Tank Capacity 7.0 liters (1.85 U.S. gal.)
Ignition System Flywheel Magneto (Solid State)
Spark Plug NGK BP6ES
Charging Capacity ---------- 12V-1.3A ---------- 12V-1.3A
Starting System Recoil Starter Electric Starter
&Recoil Starter Recoil Starter Electric Starter &Recoil Starter
Speed Reduction 1/2 Camshaft Drive ----------
Governor System Centrifugal Flyweight Type
Air Cleaner Double Element Type
Dry Weight 32.0 kg (70.6 lb.) 35.0 kg (77.2 lb.) 31.0 kg (68.4 lb.) 34.0 kg (75.0 lb.)
Dimensions (L x W x H) 389 mm x 431 mm x 433 mm (15.31 in. x 16.97 in. x 17.05 in.)

- 2 -
Specifications are subject to change without notice.
MODEL EH41
EH41B EH41BS EH41D EH41DS
Type Air-Cooled, 4-Cycle, Single-Cylinder,
Horizontal P.T.O. Shaft, OHV Gasoline Engine
Bore x Stroke 89 x 65 mm (3.50 x 2.56 in.)
Piston Displacement 404 cm
3
(24.65 cu.in.)
Compression Ratio 8.3
Output Continuous 7.0 kW (9.5 HP) /1800 r.p.m. 7.0 kW (9.5 HP) /3600 r.p.m.
Max. 9.9 kW (13.5 HP) /1800 r.p.m. 9.9 kW (13.5 HP) /3600 r.p.m.
Max. Torque 56.8 N
・ m(5.80 kgf ・ m)
/1250 r.p.m. 28.4 N
・ m(2.90kgf ・ m)
/2500 r.p.m.
Direction of Rotation Counterclockwise As Viewed From P.T.O. Shaft Side
Cooling system Forced Air Cooling
Valve Arrangement Overhead Valve
Lubrication Splash Type
Lubricant Automobile Oil SAE #20, #30 or 10W-30 ; Class SE or higher
Capacity of Lubricant 1.2 liters (0.32 U.S. gal.)
Carburetor Horizontal Draft, Float Type
Fuel Automobile Unleaded Gasoline
Fuel Consumption Ratio 310 g/kW
・ h(230 g/HP ・ h) At Continuous Rated Output
Fuel Feed System Gravity Type
Fuel Tank Capacity 7.0 liters (1.85 U.S. gal.)
Ignition System Flywheel Magneto (Solid State)
Spark Plug NGK BP6ES
Charging Capacity ---------- 12V-1.3A ---------- 12V-1.3A
Starting System Recoil Starter Electric Starter
&Recoil Starter Recoil Starter Electric Starter &Recoil Starter
Speed Reduction 1/2 Camshaft Drive ----------
Governor System Centrifugal Flyweight Type
Air Cleaner Double Element Type
Dry Weight 32.0 kg (70.6 lb.) 35.0 kg (77.2 lb.) 31.0 kg (68.4 lb.) 34.0 kg (75.0 lb.)
Dimensions (L x W x H) 389 mm x 431 mm x 433 mm (15.31 in. x 16.97 in. x 17.05 in.)

- 3 -
2. PERFORMANCE
2-1 MAXIMUM OUTPUT
The maximum output is the output of an engine with its throttle valve fully opened under the condition that
all the moving parts are properly broken in after the initial break-in period.
A new engine may not produce full maximum output while its moving parts are still not broken-in.
NOTE :
Power curves shown in the following charts are made in conformity with SAE internal combustion engine
standard test code J1349.
2-2 CONTINUOUS RATED OUTPUT
The continuous rated output is the output of an engine at optimum governed speed which is most favor-
able from the view point of engine's life and fuel consumption.
When the engine is installed on a certain equipment, it is recommended that the continuous output
required from the engine be kept below this continuous rated output.
2-3 MAXIMUM TORQUE
The maximum torque is the torque at the output shaft when the engine is producing maximum output at
certain revolution.

- 4 -
2-4 PERFORMANCE CURVES
EH36
11
6
7
8
9
10
REVOLUTION
OUTPUT
TORQUE
5
4
3
20 24 28 32 36 x10
2
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
kWHP
12
N
• mkgf • m
(52) 26
(54) 27
(5.2) 2.6
(5.4) 2.7
(5.0) 2.5
(4.8) 2.4
(4.6) 2.3
(4.4) 2.2
(50) 25
(48) 24
(46) 23
(44) 22
(5.6) 2.8
(10)(
12)( 14)( 16)( 18)
( ) for type B
MAXIMUM TORQUE
MAXIMUM HORSEPOWER
r.p.m.

- 5 -
EH41
MAXIMUM TORQUE
MAXIMUM HORSEPOWER
11
6
7
8
9
10
REVOLUTION r.p.m.
OUTPUT
TORQUE
5
4
3
20 24 28 32 36 x10
2
2.0
3.0
4.0
5.0
6.0
7.0
8.0
kWHP
12
13
9.0
N
• mkgf • m
(52) 26
(54) 27
(5.2) 2.6
(5.4) 2.7
14 10.0
(5.6) 2.8
(5.8) 2.9 (56) 28
(10)(
12)( 14)( 16)( 18)
( ) for type B

- 6 -
3. FEATURES
1. The overhead valve design offers a compactness, light weight and ideal combustion characteristics
resulting in more power from less fuel and prolonged engine life.
2. The adoption of an inclined cylinder offers low height of engine, making the arrangements for installing
the engine much easier for various powered equipments.
3. The vibration free design with a balancer system and lighter reciprocating parts.
4. Combustion and mechanical noises have been analized acoustically and improved for better tonal
quality and lower engine noise.
5. The automatic decompression system lightens the recoil pull force by 50% comparing to the conven-
tional SV engine.

- 7 -
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS
4-1 CYLINDER AND CRANKCASE
The cylinder and crankcase is a single piece alu-
minum die-casting.
The cylinder liner, made of special cast iron, is
molded into the aluminum casting.
The crankcase has a mounting surface on the out-
put shaft side, where the main bearing cover is
attached.
4-2 MAIN BEARING COVER
The main bearing cover is an aluminum die-cast-
ing, which is mounted on the output shaft side of
the crankcase.
Remove the main bearing cover to inspect inside
of the engine.
Pilots and bosses are machined on the cover for
direct mounting of the engine onto such machines
as generators and pumps.
Oil gauges (fillers) are on both sides of the cover
for easy maintenance.
4-3 CRANKSHAFT
The crankshaft is forged carbon steel, and the
crank pin is induction-hardened.
The output end of the shaft has a crankshaft gear
and balancer gear that are pressed into position.
Fig. 4-1
Fig. 4-2
Fig. 4-3
OIL GAUGE
OIL GAUGE
TYPE D
TYPE B

- 8 -
4-4 CONNECTING ROD AND PISTON
The connecting rod is an aluminum alloy die-cast-
ing and its large and small ends function as bear-
ings.
The piston is an aluminum alloy casting, and car-
ries two compression rings and one oil ring.
4-5 PISTON RINGS
The piston rings are made of special cast iron.
The profile of the top ring is a barrel face and the
second ring has a tapered face.
The oil ring is designed for better sealing and less
oil consumption, in combination with 3 pieces.
4-6 CAMSHAFT
The camshaft for the D-type engine is made of
special cast iron and camshaft gears are casted
together in one piece.
Both sides of the shaft fit into the plane bearings
on the crankcase and main bearing cover.
The camshaft for B-type engine is made of forged
carbon steel and also functions as PTO shaft.
Cam gear is press fitted on the shaft and ball bear-
ings are employed on the both sides for support-
ing the shaft.
Fig. 4-4
Fig. 4-6
TYPE D
TYPE B
Fig. 4-5
TOP
RING
SECOND
RING
OIL
RING
1
2
3
BARREL
TAPER
COMBINATION
RING
1
2
3

- 9 -
4-7 VALVE ARRANGEMENT
The intake valve is located on flywheel side of the
cylinder head.
Hard alloy valve seats are molded in the cylinder
head and stellite is fused to the exhaust valve face.
The cylinder baffle leads cooling air to the exhaust
valve area for the optimum cooling.
4-8 CYLINDER HEAD
The cylinder head is an aluminum die-casting
which utilizes semi-spherical type combustion
chamber for the high combustion efficiency.
4-9 GOVERNOR SYSTEM
The governor is a centrifugal flyweight type which
ensures constant operation at the selected speed
against load variations.
The governor gear with governor weights is in-
stalled on the main bearing cover.
Fig. 4-7
Fig. 4-8
Fig. 4-9
EXHAUST VALVE INTAKE VALVE
GOVERNOR GEAR

- 10 -
4-10 COOLING SYSTEM
The large fins on the flywheel provide sufficient
cooling air capacity for the inlet and exhaust area
and cylinder.
The cylinder baffle helps the cooling air flow effi-
ciently.
4-11 LUBRICATION SYSTEM
All the rotating and sliding parts are splash- lubri-
cated by the oil splasher on the connecting rod.
4-12 IGNITION SYSTEM
The ignition system is a transistor controlled mag-
neto system which consists of a flywheel and an
ignition coil with a built-in transistor mounted on
the crankcase.
This system has an automatic ignition timing ad-
vance characteristic for easy starting.
Fig. 4-10
Fig. 4-11
OIL SPLASHER
FLYWHEEL
IGNITION COIL

- 11 -
4-13 CARBURETOR
The engine is equipped with a horizontal draft car-
buretor that has a float controlled fuel system and
a fixed main jet.
The carburetors are calibrated carefully for sure
starting, good acceleration, less fuel consumption
and sufficient output.
For details, refer to page 47, section “8 CARBU-
RETOR”.
4-14 AIR CLEANER
Air-cleaner is a heavy-duty type with a dual ele-
ment system ; the primary one is an urethane foam
(semi-wet) and secondary one is a dry type pa-
per element.
4-15 BALANCER
Unbalanced inertia force is cancelled by the bal-
ancer which rotates in the same speed as the
crankshaft to effectively reduce vibration.
Fig. 4-12
Fig. 4-13
Fig. 4-14
ELEMENT
CLEANER
CASE
URETHANE
FOAM
KNOB

- 12 -
4-16 DECOMPRESSION SYSTEM
An automatic decompression mechanism which
opens exhaust valve before the piston reaches
compression top is assembled on the camshaft
for easy starting.
Fig. 4-15
RETURN SPRING
AUTOMATIC DECOMPRESSION SYSTEM

- 13 -
4-17 SECTIONAL VIEW OF ENGINE
Fig. 4-16
MUFFLER
P.T.O. SHAFT
AIR CLEANER
CARBURETOR
RECOIL STARTER
FLYWHEELMAIN BEARING COVER

- 14 -
Fig. 4-17
FUEL TANK
BALANCER SHAFT
ROCKER ARM
PISTON
INTAKE VALVE
(EXHAUST VALVE)
PISTON RING
PISTON PIN
PUSH ROD
CONNECTING ROD
TAPPET
CAMSHAFT
CRANKCASECRANKSHAFT
SPARK PLUG
GOVERNOR GEAR

- 15 -
5. DISASSEMBLY AND REASSEMBLY
5-1 PREPARATIONS AND SUGGESTIONS
1) When disassembling the engine, memorize the locations of individual parts so that they can be
reassembled correctly. If you are uncertain of identifying some parts, it is suggested that tags be
attached to them.
2) Have boxes ready to keep disassembled parts by group.
3) To prevent losing and misplacing, temporarily assemble each group of disassembled parts.
4) Carefully handle disassembled parts, and clean them with washing oil if necessary.
5) Use the correct tools in the correct way.
5-2 SPECIAL TOOLS
Fig. 5-1
FLYWHEEL PULLER
.oNlooTlooTesU
70-40059-902tlobhtiwrellupleehwylFleehwylfehtffognilluproF

- 16 -
5-3 DISASSEMBLY PROCEDURES
Fig. 5-2
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1
niardlioenignEniarddnagulpniardlioevomeR)1( .lio evomer,ylkciuqlioegrahcsidoT)2( .eguaglio
OIL LEVEL GAUGE
OIL DRAIN PLUG
OIL LEVEL GAUGE
GASKET
GASKET
GASKET
STEP 1

- 17 -
Fig. 5-3
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2stnemelednarevocrenaelcriA tunpac
3teksagdnaesabrenaelcriA rednilycmorfepiprehtaerbevomeR .daeh :tunegnalf6M .scp2 .ecp1:82x6M
CAP NUT
CLEANER
COVER
M6 FLANGE BOLT
: 1 pce.
CLEANER
ELEMENT
M6 FLANGE NUT
: 2 pcs.
CLEANER
BASE
GASKET
STEP 2
STEP 3