SERVICE
MANUAL
Models
EH09,
EH12-2 Rammer
ENGINES
PUB-ES1330
Rev. 12/01
940 Lively Blvd. • Wood Dale, IL 60191 • Phone: 630-350-8200 • Fax: 630-350-8212
e-mail: sales@robinamerica.com • www.robinamerica.com
© Copyright 2001 Robin America, Inc.
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 ............................................................................................................ 10
4-14 AIR CLEANER .............................................................................................................. 11
4-15 DECOMPRESSION SYSTEM ...................................................................................... 11
4-16 SECTIONAL VIEW OF ENGINE .................................................................................. 12
5. DISASSEMBLY AND REASSEMBLY ....................................................................... 16
5-1 PREPARATIONS AND SUGGESTIONS ........................................................................ 16
5-2 SPECIAL TOOLS (EH12-2D) ......................................................................................... 16
5-3 DISASSEMBLY PROCEDURES .................................................................................... 17
5-4 REASSEMBLY PROCEDURES ..................................................................................... 30
5-5 BREAK-IN OPERATION ................................................................................................ 46
6. MAGNETO ................................................................................................................ 46
6-1 OPERATION AND FUNCTION ...................................................................................... 46
6-2 BASIC THEORY ............................................................................................................ 46
6-3 WIRING DIAGRAM ....................................................................................................... 48
7. AUTOMATIC DECOMPRESSION SYSTEM ............................................................. 49
8a. FLOAT TYPE CARBURETOR (EH09D) ................................................................. 50
8a-1 OPERATION AND CONSTRUCTION .......................................................................... 50
8a-2 DISASSEMBLY AND REASSEMBLY........................................................................... 51
Section
Title
Page
8b. FLOAT TYPE CARBURETOR (EH12-2D) ............................................................. 53
8b-1 OPERATION AND CONSTRUCTION .......................................................................... 53
8b-2 DISASSEMBLY AND REASSEMBLY...........................................................................54
8c. DIAPHRAGM TYPE CARBURETOR (OPTION) ................................................... 56
8c-1 OPERATION AND CONSTRUCTION .......................................................................... 56
8c-2 DISASSEMBLY PROCEDURE .................................................................................... 59
8c-3 INSPECTION PROCEDURE ......................................................................................59
8c-4 REASSEMBLY PROCEDURE .....................................................................................60
8c-5 DIAPHRAGM CARBURETOR ADJUSTMENT METHOD ............................................ 61
9. STARTING SYSTEM .................................................................................................62
9-1 RECOIL STARTER ........................................................................................................62
10. TROUBLESHOOTING ........................................................................................... 66
10-1 STARTING DIFFICULTIES .......................................................................................... 66
10-2 ENGINE MISFIRE ........................................................................................................67
10-3 ENGINE STOPS ..........................................................................................................67
10-4 ENGINE OVERHEAT ................................................................................................... 68
10-5 ENGINE KNOCKS .......................................................................................................68
10-6 ENGINE BACKFIRES THROUGH CARBURETOR ..................................................... 68
11. INSTALLATION ..................................................................................................... 69
11-1 INSTALLING .................................................................................................................69
11-2 VENTILATION ..............................................................................................................69
11-3 EXHAUST GAS DISCHARGE .....................................................................................69
11-4 POWER TRANSMISSION TO DRIVEN MACHINES ................................................... 69
12. SERVICE DATA ...................................................................................................... 70
12-1 CLEARANCE DATA AND LIMITS ................................................................................ 70
12-2 TORQUE SPECIFICATIONS .......................................................................................76
12-3 OIL GRADE CHART ....................................................................................................76
13. MAINTENANCE AND STORAGE .......................................................................... 77
13-1 DAILY MAINTENANCE ................................................................................................77
13-2 INITIAL 20 HRS. MAINTENANCE ...............................................................................77
13-3 EVERY 50 HRS. (10 DAYS) MAINTENANCE ............................................................. 77
13-4 EVERY 100-200 HRS. (MONTHLY) MAINTENANCE ................................................. 78
13-5 EVERY 300 HRS. or YEARLY MAINTENANCE .......................................................... 78
13-6 EVERY 500-600 HRS. MAINTENANCE ...................................................................... 78
13-7 EVERY 1000 HRS. (YEARLY) MAINTENANCE .......................................................... 78
13-8 ENGINE STORAGE ..................................................................................................... 78
1. SPECIFICATIONS
MODEL
EH09D
Air-Cooled, 4-Cycle, Single-Cylinder,
Horizontal P.T.O. Shaft, OHV Gasoline Engine
Type
Bore x Stroke
51 x 42 mm (2.01 x 1.65 in.)
Piston Displacement
86 cm3 (5.24 cu.in.)
Compression Ratio
9.5
Continuous
1.4 kW (1.9 HP) /3600 r.p.m.
Max.
1.8 kW (2.4 HP) /3600 r.p.m.
Output
Max. Torque
Direction of Rotation
4.8 N・m (0.49 kgf・m) /3200 r.p.m.
Counterclockwise As Viewed From P.T.O. Shaft Side
Cooling system
Forced Air Cooling
Valve Arrangement
Overhead Valve
Lubrication
Lubricant
Splash Type
Automobile Oil SAE #20, #30 or 10W-30 ; Class SE or higher
Capacity of Lubricant
Carburetor
0.3 liters (0.079 U.S. gal.)
Horizontal Draft, Float Type or Diaphragm
Fuel
Fuel Consumption Ratio
Automobile Unleaded Gasoline
310 g/kW・h (230 g/HP・h) At Continuous Rated Output
Fuel Feed System
Gravity Type
Ignition System
Flywheel Magneto (Solid State)
Spark Plug
NGK BM6A, BMR6A
Starting System
Recoil Starter
Governor System
Centrifugal Flyweight Type
Air Cleaner
Dual Element Type
Dry Weight
9.4 kg (20.7 lb.)
Dimensions (L x W x H)
232 mm x 295 mm x 330 mm (9.1 in. x 11.6 in. x 13.0 in.)
Specifications are subject to change without notice.
- 1-
MODEL
EH12-2D
Air-Cooled, 4-Cycle, Single-Cylinder,
Horizontal P.T.O. Shaft, OHV Gasoline Engine
Type
Bore x Stroke
60 x 43 mm (2.36 x 1.69 in.)
Piston Displacement
121 cm3 (7.39 cu. in.)
Compression Ratio
9.0
Continuous
2.1 kW (2.8 HP) /3600 r.p.m.
Max.
2.6 kW (3.5 HP) /3600 r.p.m.
Output
Max. Torque
Direction of Rotation
7.5 N・m (0.76 kgf・m) /2600 r.p.m.
Counterclockwise As Viewed From P.T.O. Shaft Side
Cooling system
Forced Air Cooling
Valve Arrangement
Overhead Valve
Lubrication
Lubricant
Splash Type
Automobile Oil SAE #20, #30 or 10W-30 ; Class SE or higher
Capacity of Lubricant
Carburetor
0.4 liters (0.11 U.S. gal.)
Horizontal Draft, Float Type or Diaphragm
Fuel
Fuel Consumption Ratio
Automobile Unleaded Gasoline
310 g/kW・h (230 g/HP・h) At Continuous Rated Output
Fuel Feed System
Gravity Type
Ignition System
Flywheel Magneto (Solid State)
Spark Plug
NGK B6ES, BR6ES
Starting System
Recoil Starter
Governor System
Centrifugal Flyweight Type
Air Cleaner
Dual Element Type
Dry Weight
15.9 kg (35.1 lb.)
Dimensions (L x W x H)
286 mm x 330 mm x 334 mm (11.3 in. x 13.0 in. x 13.1 in.)
Specifications are subject to change without notice.
- 2-
2. PERFORMANCE
2-1 MAXIMUM OUTPUT
The maximum output is the output of an engine with its throttle valve fully opened and considering that all
the moving parts are properly broken in.
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 favorable 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
a specified r.p.m..
- 3-
2-4 PERFORMANCE CURVES
EH09D
N・m kgf・m
6
0.6
5
0.5
4
0.4
HP kW
3
MAXIMUM HORSEPOWER
2
CONTINUOUS
RATED HP
OUTPUT
2
1
RECOMMENDED
HORSEPOWER
RANGE
1
0
0
2000
3000
4000
REVOLUTION
r.p.m.
- 4-
TORQUE
MAXIMUM TORQUE
EH12-2D
kW
HP
3
4
7
0.7
6
0.6
MAXIMUM TORQUE
MAXIMUM HORSEPOWER
3
2
OUTPUT
CONTINUOUS RATED HP
2
RECOMMENDED
HORSEPOWER
RANGE
1
1
0
2000
3000
REVOLUTION r.p.m.
- 5-
4000
TORQUE
N・m kgf・m
8 0.8
3. FEATURES
1. The EH09D and EH12-2D engines are designed exclusively for rammers.
Optimum lubrication and better inclined operation are obtained thanks to upright cylinder design.
2. Easy operation
These engines, with its upright cylinder, reduce swinging moment and achieved easier operation for
rammers.
Because the direction of vibratory force caused by reciprocating parts, such as piston and connecting
rod, is the same as the jumping direction of the rammer itself. Furthermore, these engines are designed carefully to balance the weight on the rammer by locating the air cleaner and muffler symmetrically with the center line of the cylinder.
3. Improved durability
Vibration damping and durability are greatly improved by introducing a vibration-proof breather mechanism, thick sheet metal, reinforced casting parts with thick walls and ribs, and a carburetor that prevents fuel leakage when the engine is inclined.
4. Ideal engine performance for rammer
The overhead valve design offers ideal combustion characteristics.
More emphasis was placed on the continuous rated power of the engine than its maximum power,
considering operating characteristics when the engine is mounted on a rammer.
5. Easy starting
Combining an ignition system with an advanced spark timing and mechanical compression release
improves start-ability. Equipped with a low-speed governor, it can be started without operating the
throttle.
6. Economical and clean engine
These engines achieved fuel-efficiency and cleanliness, reducing polluting exhaust emission remarkably.
- 6-
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS
4-1 CYLINDER AND CRANKCASE
The cylinder and crankcase is a single piece aluminum die-casting.
The cylinder liner, made of special cast iron, is
molded into the aluminum casting.
The crankcase has a mounting surface on the output shaft side, where the main bearing cover is
attached.
Fig. 4-1
4-2 MAIN BEARING COVER
The main bearing cover is an aluminum die-casting with thick reinforcing walls and ribs, which is
mounted on the output shaft side of the crankcase.
OIL GAUGE
Remove the main bearing cover to inspect the inside of the engine.
Pilots and bosses are machined on the cover for
direct mounting of the engine onto rammers.
Fig. 4-2
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
that is pressed into position.
Fig. 4-3
- 7-
4-4 CONNECTING ROD AND PISTON
The connecting rod is an aluminum alloy die-casting and its large and small ends function as bearings.
The piston is an aluminum alloy casting, and carries two compression rings and one oil ring.
Model: EH09D
4-5 PISTON RINGS
Model: EH12-2D
The piston rings are made of special cast iron.
Fig. 4-4
The profile of the top ring and the second ring are
shown in the illustration.
The oil ring is designed for better sealing and less
oil consumption.
①
②
1
TOP
RING
2
SECOND
RING
③
3
OIL
RING
EH09D
EH12-2D
BARREL
EH09D
TAPER
EH12-2D
TAPER
UNDER CUT
EH09D
CUTTER RING
EH12-2D
CUTTER RING WITH
COIL EXPANDER
Fig. 4-5
4-6 CAMSHAFT
The camshaft is made of special cast iron, and
camshaft and gear are cast together in one piece.
Both sides of the shaft fit into the plain bearings
on the crankcase and main bearing cover.
Fig. 4-6
- 8-
4-7 VALVE ARRANGEMENT
The intake valve is located on the flywheel side of the cylinder head.
Hard alloy valve seats are molded in the cylinder head and satellite is fused to the exhaust valve face.
The cylinder baffle leads cooling air to the exhaust valve area for the optimum cooling.
IN
EX
IN
EXHAUST
VALVE
INTAKE
VALVE
EXHAUST
VALVE
INTAKE
VALVE
EX
Model: EH09D
Model: EH12-2D
Fig. 4-7a
Fig. 4-7b
4-8 CYLINDER HEAD
The cylinder head is an aluminum die-casting
which utilizes wedge type combustion chamber
for the high combustion efficiency.
Fig. 4-8
4-9 GOVERNOR SYSTEM
The governor is a centrifugal flyweight type which
ensures constant operation at the selected speed
during load variations.
The governor gear with governor weights is installed on the main bearing cover.
GOVERNOR GEAR
Fig. 4-9
- 9-
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 directs the cooling air flow efficiently.
4-11 LUBRICATION SYSTEM
All the rotating and sliding parts are splash- lubricated by the oil splasher on the connecting rod.
OIL SPLASHER
Fig. 4-10
4-12 IGNITION SYSTEM
The ignition system is a transistor controlled magneto system which consists of a flywheel and an
ignition coil with a built-in transistor mounted on
the crankcase.
IGNITION COIL
This system has an automatic ignition timing advance system for easy starting.
FLYWHEEL
Fig. 4-11
4-13 CARBURETOR
The engine is equipped with a horizontal draft carburetor 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 maximum output.
For details, refer to page 50, section “8a FLOAT
CARBURETOR (EH09D)” or refer to page 53,
section “8b FLOAT CARBURETOR (EH12-2D)”.
As an optional part, diaphragm type is available.
For details, refer to page 56, section “8c DIAPHRAGM CARBURETOR (OPTION)”.
- 10 -
FLOAT TYPE
DIAPHRAGM TYPE
Fig. 4-12
4-14 AIR CLEANER
The air-cleaner is a heavy-duty type with a dual
element system ; the primary one is an urethane
foam (semi-wet) and secondary one is a semi wet
type element.
URETHANE FOAM
CLEANER
COVER
CLEANER BASE
ELEMENT
Model: EH09D
Fig. 4-13a
CLEANER BASE
ELEMENT
CLEANER
COVER
PLATE,
AIR CLEANER
ELEMENT SET
Model: EH12-2D
;
;;
;;
;;
Fig. 4-13b
4-15 DECOMPRESSION SYSTEM
AUTOMATIC DECOMPRESSION SYSTEM
An automatic decompression mechanism which
opens the exhaust valve before the piston reaches
maximum compression is assembled on the camshaft for easy starting.
During engine operation the decompression system is overpowered by centrifugal force and compression is fully utilized to produce power.
RETURN SPRING
Fig. 4-14
- 11 -
4-16 SECTIONAL VIEW OF ENGINE
EH09D
INTAKE VALVE
CYLINDER HEAD
EXHAUST VALVE
MUFFLER
PISTON PIN
IGNITION COIL
PISTON
BLOWER HOUSING
PISTON RING
RECOIL STARTER
P.T.O. SHAFT
MAIN
BEARING
COVER
ADAPTER
(FLANGE)
FLYWHEEL
CRANKCASE
Fig. 4-15
- 12 -
PUSH ROD
ROCKER COVER
CARBURETOR
ROCKER ARM
AIR CLEANER
SPARK PLUG
TAPPET
CAMSHAFT
CONNECTING ROD
GOVERNOR LEVER
SPEED CONTROL
LEVER
OIL GAUGE
CRANKSHAFT
PLUG
STIFFENER
Fig. 4-16
- 13 -
EH12-2D
INTAKE VALVE
EXHAUST VALVE
CYLINDER HEAD
IGNITION COIL
PISTON
BLOWER HOUSING
PISTON PIN
PISTON RING
P.T.O. SHAFT
MAIN
BEARING
COVER
RECOIL STARTER
FLYWHEEL
CRANKCASE
Fig. 4-17
- 14 -
PUSH ROD
ROCKER COVER
CARBURETOR
ROCKER ARM
AIR CLEANER
SPARK PLUG
MUFFLER
TAPPET
GOVERNOR
LEVER
CAMSHAFT
CONNECTING ROD
SPEED CONTROL
LEVER
OIL GAUGE
PLUG
CRANKSHAFT
Fig. 4-18
- 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 (EH12-2D)
Tool No.
Tool
Use
Market parts
Flywheel puller
For pulling off the flywheel
FLYWHEEL PULLER
Fig. 5-1
- 16 -
5-3 DISASSEMBLY PROCEDURES
Step
1
Parts to remove
Remarks and procedures
(1) Remove oil drain plug and drain oil.
(2) To discharge oil quickly, remove oil
gauge.
Engine oil drain
M8 x 25 : 4 pcs.
M8 x 30 : 2 pcs.
M8 nut, washer,
spring washer :
4pcs
EH09D
2
Fasteners
Adapter and Stiffener
STEP 1
OIL LEVEL GAUGE
GASKET
EH09D
M8 WASHER
: 4 pcs.
M8 NUT
: 4 pcs.
OIL DRAIN
PLUG
GASKET
M8 SPRING
WASHER : 4 pcs.
ADAPTER
STEP 2
STIFFENER
M8 x 30 BOLT AND
WASHER : 2 pcs.
M8 x 25 BOLT AND
WASHER : 4 pcs.
- 17 -
Fig. 5-2
Step
Parts to remove
3
Remarks and procedures
Fasteners
M6 x 12 ; 3 pcs.
(EH09D)
M6 x 8 ; 4 pcs.
(EH12-2D)
Recoil starter
Disconnect wire of stop switch first, then
remove blower housing from crankcase.
4
M6 x 12 ; 5 pcs.
(EH09D)
M6 x 8 ; 2 pcs.
(EH09D)
M6 x 55 ; 4 pcs.
(EH12-2D)
Blower housing
EH09D
M4 TAPPING SCREW : 2 pcs.
STEP 4
M6 x 12 FLANGE BOLT : 1 pce.
M6 x 12 FLANGE
BOLT : 2 pcs.
STOP SWITCH
CLAMP
M6 x 12 FLANGE
BOLT : 3 pcs.
STEP 3
M6 x 8 FLANGE BOLT
: 1 pce.
M6 x 12 FLANGE
BOLT : 1 pce.
BLOWER
GUIDE CP
RECOIL
STARTER
M6 x 12 FLANGE
BOLT: 1 pce.
M6 x 8 FLANGE
BOLT: 1 pce.
BLOWER HOUSING CP
CLAMP
EH12-2D
STEP 4
M4 TAPPING
SCREW : 2 pcs.
M6 x 8 FLANGE BOLT
: 4 pcs.
STOP
SWITCH
STEP 3
RECOIL
STARTER
M6 x 55 FLANGE BOLT
: 4 pcs.
BLOWER HOUSING CP
Fig. 5-3
- 18 -
Step
Parts to remove
Remarks and procedures
Be careful not to lose muffler gasket.
M6 self lock nut ;
2 pcs.
M6 x 12 ; 2 pcs.
M6 flange nut ;
2pcs.
Remove spark plug cap first from
spark plug.
Be careful not to lose muffler gasket.
M8 self lock nut ;
2 pcs.
M8 x 16 ; 4 pcs.
M8 washer ; 2
pcs.
M6 x 18 ; 2pcs.
EH09D
Muffler, muffler bracket and
cylinder baffle
5
EH12-2D
Muffler, muffler bracket and
head cover
EH09D
Fasteners
M6 x 12 BOLT AND
WASHER AY : 2 pcs.
M6 FLANGE NUT : 2 pcs.
BLOWER HOUSING
BRACKET CP 2
MUFFLER
BRACKET CP
MUFFLER CP
CYLINDER BAFFLE
GASKET
(MUFFLER)
M6 SELF LOCK
NUT : 2 pcs.
EH12-2D
Do not touch
the flange bolts.
M8 x 16 BOLT AND
WASHER AY : 2 pcs.
STEP 5
GASKET
(MUFFLER)
MUFFLER
STEP 5
SPACER
(EXHAUST)
M8 SELF LOCK
NUT : 2 pcs.
MUFFLER BRACKET
M8 x 16 BOLT AND
WASHER AY : 2 pcs.
M8 WASHER : 2 pcs.
M6 x 18 FLANGE
BOLT : 2 pcs.
HEAD COVER
- 19 -
Fig. 5-4
Step
Parts to remove
Remarks and procedures
Fasteners
Remove breather pipe from rocker cover.
6
M6 nut ; 2 pcs.
M8 x 18 ; 1 pce.
(EH12-2D)
Air cleaner
EH09D
PURSE LOCK
BREATHER PIPE
STEP 6
CLEANER BASE
URETHANE FOAM
ELEMENT
CLEANER COVER
M6 SELF LOCK NUT : 2 pcs.
EH12-2D
BOTTOM PLATE
PLATE (AIR CLEANER)
STEP 6
ELEMENT
ELEMENT SET
WASHER
M6 NUT : 2 pcs.
BREATHER PIPE
CLAMP
M8 x 18 BOLT AND
SPRING WASHER AY : 1 pce.
Fig. 5-5
- 20 -
CLEANER COVER
EH09D
Step
Parts to remove
Remarks and procedures
Fasteners
Governor lever
(1) Loosen the bolt and remove governor
lever.
(2) Unhook governor spring from governor
lever.
Mark the hole on which the governor
spring is hooked.
8
Carburetor
Remove carburetor carefully unhooking
governor rod and rod spring from governor
lever.
9
Speed control lever and
base plate
7
M6 x 25 ; 1 pce.
M6 pivot bolt ;
1 pce.
M6 x 8 flange
bolt ; 2 pcs.
M6 x 8 FLANGE
BOLT : 2 pcs.
STEP 9
SPACER
SPEED CONTROL
LEVER AY
FRICTION WASHER
M6 PIVOT BOLT
: 1 pce.
RETURN
SPRING
BASE
PLATE CP
GASKET (INSULATOR)
CARBURETOR
ROD SPRING
INSULATOR
GOVERNOR ROD
GOVERNOR LEVER
STEP 8
GOVERNOR SPRING
M6 BOLT AND
WASHER AY : 1 pce.
Fig. 5-6
- 21 -
STEP 7
EH12-2D
Step
Parts to remove
Remarks and procedures
Fasteners
M8 x 16 ; 1 pce.
M6 x 14; 1pce.
M6 x 30 ; 1pce.
(1) Remove the protector.
(2) Loosen the bolt and remove governor
lever.
(3) Unhook governor spring from governor
lever.
Mark the hole on which the governor
spring is hooked.
7
Governor lever
8
Carburetor and intake
pipe
9
Speed control lever and
wire bracket
Remove carburetor carefully unhooking
governor rod and rod spring from governor
lever.
M6 nut ; 2 pcs.
M6 x 40 ; 1 pce.
M6 pivot bolt ;
1 pce.
M6 x 14 flange
bolt ; 1 pcs.
M6 NUT : 2 pcs.
GASKET
M6 x 40 BOLT AND
WASHER : 1 pce.
INSULATOR
STEP 8
CARBURETOR
INTAKE
PIPE
GASKET
(INSULATOR)
ROD SPRING
GOVERNOR
LEVER
GOVERNOR
ROD
STEP 9
M6 PIVOT BOLT : 1 pce.
GOVERNOR
SPRING
SPEED CONTROL LEVER
STEP 7
NUT
M6 x 12 FLANGE
M6 BOLT AND
BOLT : 1 pce.
WASHER AY : 1 pce.
PROTECTOR
STEP 9
WIRE BRACKET
M6 x14 FLANGE BOLT : 1 pce.
Fig. 5-7
- 22 -
M8 x 16 BOLT AND
WASHER AY : 1 pce.
Step
10
Parts to remove
Ignition coil
Remarks and procedures
Fasteners
(1) Remove spark plug cap from spark plug.
(2) Remove ignition coil from crankcase.
M6 x 25 ; 2 pcs.
(1) Remove the starter pulley from flywheel.
Place socket wrench on flywheel fastening nut
and strike tip of the lever with hammer. (See
Fig. 5-9.)
(2)
11
Flywheel
EH09D
Tap on flywheel end of crankshaft using
aluminum bar to remove flywheel.
(See Fig. 5-10.)
M12 nut, spring
washer
EH12-2D
Remove flywheel using the flywheel puller.
(See Fig. 5-11.)
(3) Remove the key from crankshaft.(See Fig. 5-12.)
12
Spark plug
M14 nut, spring
washer
NGK : BM6A, BMR6A (EH09D)
NGK : B6ES, BR6ES (EH12-2D)
ALUMINUM BAR
Fig. 5-9
SPARK PLUG CAP
SPARK
PLUG
STEP 12
Fig. 5-10
IGNITION COIL CP
Fig. 5-11
M12 SPRING WASHER : 1 pce. (EH09D)
M14 SPRING WASHER : 1 pce. (EH12-2D)
STEP 10
STARTING
PULLEY
M6 x 25 BOLT AND
WASHER AY
: 2 pcs.
FLYWHEEL CP
M12 NUT : 1 pce. (EH09D)
M14 NUT : 1 pce. (EH12-2D)
STEP 11
WOODRUFF KEY
Fig. 5-8
- 23 -
Fig. 5-12
Step
13
14
Parts to remove
Rocker cover
Cylinder head
Remarks and procedures
Fasteners
Remove rocker cover and gasket from
cylinder head.
M6 x 60 ; 4 pcs.
(EH09D)
M6 x 40 ; 4 pcs.
(EH12-2D)
(1) Remove cylinder head and gasket from
crankcase.
(2) Remove push rods from cylinder.
M8 x 55 ; 4 pcs.
(EH09D)
M8 x 65 ; 4 pcs.
(EH12-2D)
EH09D
EH12-2D
M6 x 60 BOLT AND
WASHER AY : 4 pcs.
M6 x 40 FLANGE
BOLT : 4 pcs.
STEP 13
ROCKER COVER
STEP 13
ROCKER COVER
M8 x 55 FLANGE
BOLT : 4 pcs.
GASKET
GASKET
M8 x 65 FLANGE
BOLT : 4 pcs.
SPACER
(BREATHER)
GASKET
CYLINDER
HEAD CP
PUSH ROD
STEP 14
GASKET
CYLINDER
HEAD CP
STEP 14
GASKET
PUSH ROD
Fig. 5-13
- 24 -
Step
Parts to remove
Remarks and procedures
Fasteners
Be careful not to damage the oil seal.
Use a soft hammer and evenly tap around
outer surface of cover.
EH09D
Main bearing cover
15
M6 x 30 ; 9 pcs.
M8 x 16 ; 3 pcs.
M6 x 16 ; 2 pcs.
M6 x 30 ; 8 pcs.
EH12-2D
Bracket (M.B.C.) and
main bearing cover
EH09D
STEP 15
Fig. 5-15
MAIN BEARING
COVER CP
M6 x 30 BOLT AND
WASHER AY : 9 pcs.
EH12-2D
SUPPORT
(MAIN BEARING COVER)
GASKET
(BREATHER COVER)
BRACKET
(MAIN BEARING
STEP 15
COVER)
MAIN BEARING COVER CP
M8 x 16 FLANGE
BOLT : 2 pcs.
M6 x 16 FLANGE
BOLT : 2 pcs.
M8 x 16 FLANGE
BOLT : 1 pce.
M6 x 30 BOLT AND
WASHER AY : 8 pcs.
Fig. 5-14
- 25 -
Step
16
Parts to remove
Camshaft and tappets
Remarks and procedures
Fasteners
Lay carnkcase on the flywheel side push
tappets up into the block and remove
camshaft.
Be careful not to damage camshaft and
tappets.
TAPPET
STEP 16
Fig. 5-17
CAMSHAFT
CAMSHAFT
Fig. 5-16
- 26 -
Step
Parts to remove
Remarks and procedures
Connecting rod and
piston
(1) Remove connecting rod bolts and
connecting rod cap.
(2) Turn crankshaft until piston comes to top
dead center, push out connecting rod and
piston assembly through top of cylinder.
*Scrape off all carbon deposits that might
interfere with removal of piston from
upper end of cylinder.
Piston and piston pin
(1) Remove clips and piston pin to remove
connecting rod from piston.
(2) Remove piston rings from piston.
*Be careful not to damage the piston
and connecting rod.
Be careful not to break rings by spreading
too much or twisting.
17
EH09D
Fasteners
M5 x 25 ; 2 pcs
(EH09D)
M6 x 34 ; 2 pcs
(EH12-2D)
EH12-2D
CLIP
PISTON RING
PISTON RING
CLIP
PISTON
PISTON
PISTON PIN
CLIP
PISTON PIN
CLIP
CONNECTING ROD
CONNECTING ROD
STEP 17
STEP 17
M5 x 25
CONNECTING
ROD BOLT
: 2 pcs.
M6 x 34
CONNECTING
ROD BOLT
: 2 pcs.
Fig. 5-18
- 27 -
Step
18
Parts to remove
Crankshaft
Remarks and procedures
Fasteners
Tap lightly on flywheel end of crankshaft
with a soft hammer to remove from
crankcase.
*Be careful not to damage oil seal.
STEP 18
CRANKSHAFT
Fig. 5-19
Fig. 5-20
- 28 -
Step
Parts to remove
Intake and exhaust
valves
19
Remarks and procedures
Fasteners
(1) Press down the spring retainer, take
out collet valve, and then remove
spring retainer and valve spring.
(2) Remove intake and exhaust valves
from cylinder head.
* Clean carbon and gum deposit from the
valves, valve seats, ports and guides.
Inspect valves, valve seats and guides.
STEP 19
BOLT (PIVOT) : 2 pcs.
ROCKER ARM
COLLET
Fig. 5-22
SPRING
RETAINER
M6 NUT
: 2 pcs.
VALVE
SPRING
GUIDE PLATE
EXHAUST VALVE
INTAKE VALVE
Fig. 5-21
- 29 -
5-4 REASSEMBLY PROCEDURES
●
PRECAUTIONS FOR REASSEMBLY
1) Clean parts thoroughly before reassembly.
Pay close attention to the cleanliness of piston, cylinder, crankshaft, connecting rod and bearings.
2) Scrape off all carbon deposits from cylinder head, piston top and piston ring grooves.
3) Check lip of oil seals. Replace oil seal if the lip is damaged. Apply oil to the lip before reassembly.
4) Replace all the gaskets with new ones.
5) Replace keys, pins, bolts, nuts, etc., if necessary.
6) Torque bolts and nuts to specification refer to the "TORQUE SPECIFICATIONS" (See page 76).
7) Apply oil to rotating and sliding portions.
8) Check and adjust clearances and end plays where specified in this manual.
5-4-1 CRANKSHAFT
(1) Install crankshaft in crankcase wrapping the
keyway with polyvinyl tape to avoid damage
to oil seal.
(2) Install woodruff key for flywheel on crankshaft.
CRANKSHAFT
POLYVINYL TAPE
Fig. 5-23
5-4-2 PISTON AND PISTON RINGS
(1) Install oil ring first, then second ring and top
ring.
OPEN ENDS OF PISTON RING
Spread ring only far enough to slip over piston and into correct groove. Use care not to
distort ring.
Install second ring with punched mark beside
the gap face upward. (See Fig. 5-26a, 26b)
Fig. 5-24
- 30 -
①
②
1
TOP
RING
2
SECOND
RING
③
3
OIL
RING
EH09D
EH12-2D
BARREL
EH09D
TAPER
EH12-2D
TAPER
UNDER CUT
EH09D
CUTTER RING
EH12-2D
CUTTER RING WITH
COIL EXPANDER
Fig. 5-25
MARK "R"
MARK "RN"
Model: EH09D
Model: EH12-2D
Fig. 5-26a
Fig. 5-26b
5-4-3 PISTON AND CONNECTING ROD
(1) EH09D
The direction of piston on connecting rod is
not specified.
EH12-2D
When installing the piston on the connecting
rod, place the valve recess of the piston crown
as shown in the illustration to the “MAG” side
of the connecting rod.
(2) Apply oil to the small end of connecting rod,
piston and piston pin before assembling.
Be sure to use clips on the both side of the
piston pin to secure piston pin in position.
- 31 -
"MAG"
MARK
"MA"
MARK
VALVE RECESS
Model: EH09D
Model: EH12-2D
Fig. 5-27
(3) Install piston and connecting rod assembly
into cylinder.
PISTONRING
COMPRESSOR
Use a piston ring compressor to hold piston
rings.
CONNECTING ROD
("MA"SIDE EH09D)
("MAG"SIDE EH12-2D)
The “MA” mark (EH09D) ,“MAG” mark (EH122D) of the connecting rod is to face the flywheel side of the engine when assembled.
Note:
(1) Apply enough oil to lubricate the piston rings, connecting rod bearings
and cylinder bore before assembly.
CRANKCASE (FLYWHEEL SIDE)
Fig. 5-28
(2) Set gaps of the piston rings 90 degrees apart from each other before
assembly.
SECOND RING
OIL RING
TOP RING
5-4-4 CONNECTING ROD
Fig. 5-29
(1) Turn crankshaft to bottom dead center, lightly
tap top of the piston until large end of the rod
meet crank pin.
(2) Install connecting rod cap to connecting rod.
Make sure to match the alignment marks on
the rod caps.
Torque connecting rod bolts to specification.
M5 x 25 mm connecting rod bolt : 2 pcs. (EH09D)
M6 x 34 mm connecting rod bolt : 2 pcs. (EH12-2D)
Tightening torque
EH09D
EH12-2D
5.9 - 7.8 N・m
(60 - 80 kg・cm)
(4.3 - 5.7 ft・lb.)
8.8 - 11 N・m
(90 - 115 kg・cm)
(6.5 - 8.3 ft・lb.)
ALIGNMENT
MARK
ALIGNMENT
MARK
Model: EH09D
Fig. 5-30
(3) Check for free movement of connecting rod
by turning crankshaft slowly.
- 32 -
Model: EH12-2D
5-4-5 TAPPETS AND CAMSHAFT
(1) Oil the tappets and install them.
Push in fully to avoid damage during camshaft
installation.
CAMSHAFT
TIMING MARK
(2) Lubricate bearing surfaces of camshaft.
Align the timing mark on crankshaft gear with
the timing mark on camshaft and install camshaft in the crankcase. (See Fig. 5-31a)
CRANKSHAFT
GEAR
CAUTION :
Incorrect valve timing will cause malfunction of the engine.
Fig. 5-31a
5-4-6 ADJUST CRANKSHAFT END PLAY
(1) Adjust end play to 0.2 mm (0.008") using the
proper spacer.
The proper spacer may be determined in the
following manner.
1) Measure the height “A” (From the mating
surface to the inner race of the ball bearing.)
2) Measure the depth “B” (From the mating
surface to the crank gear.)
B-A = SIDE CLEARANCE (mm)
(SIDE CLEARANCE)-0.2 mm = THICKNESS OF CRANKSHAFT SHIM (mm)
B-A = SIDE CLEARANCE (in.)
(SIDE CLEARANCE)-0.008 in.= THICKNESS OF CRANKSHAFT SHIM (in.)
Following are available spacer shims.
CRANKSHAFT
SPACER SHIMS
T= 0.6 mm (0.024 in.)
T= 0.8 mm (0.031 in.)
T= 1.0 mm (0.039 in.)
Table. 5-1
Fig. 5-31b
- 33 -
(2) Lubricate the oil seal and bearing surfaces.
Coat the surface of the main bearing cover with sealant (Three bond 1216).
Place spacer chosen in step (1) on crankshaft.
Use an oil seal guide when installing the main bearing cover to avoid damaging the oil seal .
Tap the cover into place with a soft hammer.
Main bearing cover EH09D M6 x 30 mm bolt and washer : 9 pcs.
EH12-2D M6 x 30 mm bolt and washer : 8 pcs.
Tightening torque
EH09D, EH12-2D
9.8 - 11.8 N・m
(100 - 120 kg・cm)
(7.2 - 8.7 ft・lb.)
EH09D
SPACER
SEALANT
(Three bond 1216)
CRANKSHAFT
CAMSHAFT
CRANKCASE
M6 x 30 BOLT AND
WASHER AY : 9 pcs.
EH12-2D
MAIN BEARING
COVER CP
SEALANT
(Three bond 1216)
MAIN BEARING COVER CP
SPACER
M6 x 30 BOLT AND
WASHER AY : 8 pcs.
CRANKSHAFT
CAMSHAFT
CRANKCASE
Fig. 5-32
- 34 -
5-4-7 CYLINDER HEAD
(1) Clean carbon and gum deposits from the valves, seats, ports and guides. Inspect valves, valve seats
and valve guides.
(2) Replace valves that are badly burned, pitted or warped.
(3) When installing valves in cylinder head, oil the valve stems and insert them into valve guide.
Then place cylinder head on flat table, install valve spring and spring retainer.
(4) Valve guides should be replaced when valve stem clearance exceeds specifications (See “SERVICE
DATA”).
Draw valve guides out and press new guides in.
Refer to “SERVICE DATA” for clearance specifications.
After replacing valves and guides, lap valves in place until a uniform ring shows around the face of
the valve. Clean valves and wash cylinder head thoroughly.
(5) Install cylinder head onto cylinder with new head gasket.
Tighten four flange bolts evenly in three steps by the following tightening torque:
Cylinder head M8 x 55 mm bolt : 4 pcs. (EH09D)
Tightening torque (EH09D)
1 st step
2 nd step
Final Step
5.0 N・m
(50 kg・cm)
(3.6 ft・lb.)
9.8 N・m
(100 kg・cm)
(7.2 ft・lb.)
18.6-20.6 N・m
(190-210 kg・cm)
(13.7-15.2 ft・lb.)
Cylinder head M8 x 65 mm bolt : 4 pcs. (EH12-2D)
Tightening torque (EH12-2D)
1 st step
2 nd step
Final Step
5.0 N・m
(50 kg・cm)
(3.6 ft・lb.)
9.8 N・m
(100 kg・cm)
(7.2 ft・lb.)
23.0-26.0 N・m
(230-270 kg・cm)
(17.0-30.0 ft・lb.)
- 35 -
5-4-8 ROCKER ARMS AND PUSH RODS
(1) Insert push rods into crankcase.
Put push rod tip in the hollow of tappet top.
Note:
An oil return slot is located next to the tappet boss. If you do not put the push rod in the
tappet properly, the push rods will fall into the crankcase.
Removal of the main bearing cover is necessary to get them out.
(2) Apply oil to rocker arms and assemble them to cylinder head using pivot bolt and nut.
M6 x 60 BOLT AND
WASHER AY : 4 pcs.
ROCKER COVER
BOLT (PIVOT) : 2 pcs.
ROCKER ARM
COLLET
SPRING RETAINER
M6 NUT
: 2 pcs.
GASKET
VALVE SPRING
GUIDE PLATE
M8 x 55 FLANGE
BOLT : 4 pcs.
CYLINDER
HEAD CP
EXHAUST VALVE
INTAKE VALVE
GASKET
PUSH ROD
Fig. 5-33
- 36 -
5-4-9 VALVE CLEARANCE ADJUSTMENT
Note:
Temporally fit the flywheel in position for
easy operation.
(1) EH09D
Position the piston at the top dead center of
compression stroke by matching the alignment
mark of flywheel with the alignment mark of
crankcase.
ALIGNMENT
MARKS
FLYWHEEL
Model: EH09D
Fig. 5-34a
EH12-2D
Position the piston at the top dead center of
compression stroke. The top dead center may
be obtained by placing the key slot on the
power take off shaft to 10 o’clock position. (See
Fig. 5-34b)
45°
P.T.O
(2) Loosen the nut under the rocker arm and turn
the bolt (pivot) to adjust the clearance between
rocker arm and valve stem end.
Tighten the nut on rocker arm.
Valve clearance : 0.07 - 0.13 mm
(0.0028 - 0.0051 in.)
Model: EH12-2D
Fig. 5-34b
Note:
Check and adjust valve clearance while
engine is cold.
ROCKER ARM
THICKNESS GAUGE
Check operation of valves by turning
crankshaft. Then recheck the valve clearance.
BOLT
(PIVOT)
(3) Install rocker cover and gasket.
Rocker cover M6 x 25 mm bolt : 4 pcs.
NUT
Fig. 5-35
- 37 -
5-4-10 SPARK PLUG
Install spark plug to cylinder head.
Spark plug : NGK BM6A, BMR6A (EH09)
: NGK B6ES, BR6ES (EH12-2D)
Tightening torque (EH09D)
Tightening torque (EH12-2D)
New spark plug
Retightening
New spark plug
Retightening
11.8 - 14.7 N・m
(120 - 150 kg・cm)
(8.7 - 10.9 ft・lb.)
22.6 - 24.5 N・m
(230 - 250 kg・cm)
(16.6 - 18.1 ft・lb.)
11.8 - 14.7 N・m
(120 - 150 kg・cm)
(8.7 - 10.9 ft・lb.)
22.6 - 26.5 N・m
(230 - 270 kg・cm)
(16.6 - 19.5 ft・lb.)
5-4-11 FLYWHEEL MAGNETO
(1) Put the woodruff key in the keyway of crankshaft. Wipe off oil and grease thoroughly from
the tapered portion of crankshaft and flywheel
center hole.
(2) Install the flywheel to crankshaft.
Tighten the flywheel nut with the starter pulley.
Tightening torque
EH09D
EH12-2D
44.2 - 49.1 N・m
(450 - 500 kg・cm)
(32.5 - 36.2 ft・lb.)
59.0 - 63.0 N・m
(600 - 650 kg・cm)
(43.0 - 47.0 ft・lb.)
Fig. 5-36
- 38 -
5-4-12 IGNITION COIL
Install ignition coil to crankcase.
Pay attention the direction of ignition coil and the
location of code.
Adjust air gap between ignition coil and flywheel
using a thickness gauge and tighten bolts.
M6 x 25 mm bolt and washer : 2 pcs.
IGNITION COIL
Air gap : 0.3 - 0.5 mm
(0.012 - 0.020 in.)
Model: EH09D
THICKNESS
GAUGE
Fig. 5-37a
Tightening torque
8.8 - 10.8 N・m
(90 - 110 kg・cm)
(6.5 - 8.0 ft・lb.)
IGNITION
COIL
THICKNESS GAUGE
Model: EH12-2D
Fig. 5-37b
5-4-13 INTAKE PIPE, INSULATOR (EH12-2D)
(1) Install the intake pipe to the cylinder head with
gasket.
M6 NUT : 2 pcs.
M6 x 40 BOLT
AND WASHER AY: 1 pce.
GASKET
M6 flange nut : 2pcs.
M6 x 40 mm bolt and washer : 1pce.
Tightening torque : 9.8 - 13.7 N・m
(100 - 140 kg・cm)
(7.2 - 10.1 ft・lb.)
Then put the gasket and insulator on the intake
pipe.
INTAKE
PIPE
Fig. 5-38
- 39 -
5-4-14 GOVERNOR, SPEED CONTROL SYSTEM AND CARBURETOR
EH09D
(1) Install governor lever to governor shaft, then tighten the locking bolt temporarily.
(2) Install base plate to crankcase.
(3) Install speed control lever, friction washer, pivot bolt, etc. to base plate as shown in illustration.
(4) Hook governor spring to proper holes of governor lever and speed control lever. (See Fig. 5-40a)
(5) Install insulator and gaskets for carburetor to cylinder head.
(6) Install carburetor to cylinder head hooking governor rod to governor lever and throttle lever of carburetor. Hook rod spring over governor rod.
(7) Attach air cleaner base to carburetor. Tighten two flange nuts and a bolt. Connect breather pipe from
rocker cover to cleaner base.
M6 x 8 FLANGE
BOLT : 2 pcs.
SPACER
SPEED CONTROL
LEVER AY
FRICTION WASHER
M6 PIVOT BOLT
: 1 pce.
RETURN
SPRING
BASE
PLATE CP
GASKET (INSULATOR)
CARBURETOR
ROD SPRING
INSULATOR
GOVERNOR ROD
GOVERNOR LEVER
GOVERNOR SPRING
GOVERNOR SHAFT
M6 BOLT AND
WASHER AY : 1 pce.
Fig. 5-39a
- 40 -
EH12-2D
(1) Install governor lever to governor shaft, then tighten the locking bolt temporarily.
(2) Install speed control lever, pivot bolt, etc. as shown in illustration.
(3) Hook governor spring to proper holes of governor lever and speed control lever. (See Fig. 5-40b)
(4) Install insulator and gaskets for carburetor to intake pipe.
(5) Install carburetor to intake pipe hooking governor rod to governor lever and throttle lever of carburetor. Hook rod spring over governor rod.
(6) Attach air cleaner base to carburetor. Tighten two flange nuts and a bolt. Connect breather pipe from
rocker cover to cleaner base.
INSULATOR
CARBURETOR
ROD SPRING
GASKET
(INSULATOR)
GOVERNOR
LEVER
GOVERNOR
ROD
M6 PIVOT BOLT : 1 pce.
GOVERNOR
SPRING
SPEED CONTROL LEVER
NUT
M6 x 12 FLANGE
BOLT : 1 pce.
M6 BOLT AND
WASHER AY : 1 pce.
PROTECTOR
WIRE BRACKET
M6 x14 FLANGE BOLT : 1 pce.
Fig. 5-39b
- 41 -
M8 x 16 BOLT AND
WASHER AY : 1 pce.
5-4-15 AIR CLEANER
Install the air cleaner gasket and the cleaner base
and tighten them with 2-M6 flange nuts.
Then install the element and the cleaner case.
5-4-16 ADJUST GOVERNOR SYSTEM
(1) Turn the speed control lever all the way toward the high speed position and fix it by tightening self lock
nut.
(2) Check that the governor lever is pulled by the governor spring and carburetor throttle valve is fully
open.
(3) Turn the governor shaft clockwise all the way using a screw driver, and tighten lock bolt to secure the
lever on the shaft.
(4) Loosen the self lock nut to allow the speed control lever to move freely.
GOVERNOR
ROD SPRING
GOVERNOR ROD SPRING
GOVERNOR
ROD
GOVERNOR
SPRING
GOVERNOR
ROD
Normal hooking
position
GOVERNOR
LEVER
Normal hooking
position
GOVERNOR
LEVER
GOVERNOR
SPRING
SPEED CONTROL
LEVER
GOVERNOR
SHAFT
SPEED CONTROL
LEVER
GOVERNOR
SHAFT
Model: EH09D
Model: EH12-2D
Fig. 5-40a
Fig. 5-40b
- 42 -
5-4-17a CYLINDER BAFFLE, MUFFLER BRACKET and MUFFLER (EH09D)
(1) Temporarily install cylinder baffle, muffler
bracket and blower housing bracket 2 to the
cylinder head.
: M6 flange nut : 2 pcs.
Do not tighten the flange nut fully.
(2) Temporarily install muffler and gasket to cylinder head.
: M6 self lock nut : 2 pcs.
: M6 x 12 mm bolt and washer : 2 pcs.
(3) Finally, tighten the self lock nut etc. fully,
according to the following priority.
1 M6 self lock nut : 2 pcs.
2 M6 x 12 mm bolt and washer : 2 pcs.
3 M6 flange nut : 2 pcs.
Tightening torque
8.8 - 10.8 N・m
(90 - 110 kg・cm)
(6.5 - 8.0 ft・lb.)
3 M6 FLANGE NUT : 2 pcs.
2 M6 x 12 BOLT AND
WASHER AY : 2 pcs.
BLOWER HOUSING
BRACKET CP 2
MUFFLER
BRACKET CP
MUFFLER CP
CYLINDER BAFFLE
GASKET
(MUFFLER)
1 M6 SELF LOCK
NUT : 2 pcs.
Fig. 5-41a
- 43 -
5-4-17b HEAD COVER, MUFFLER BRACKET and MUFFLER (EH12-2D)
(1) Temporarily install head cover and muffler
bracket to cylinder head.
: M6 x 18 mm flange bolt : 2 pcs.
(2) Temporarily install muffler, gasket (muffler) and
spacer (exhaust) to cylinder head.
: M8 self lock nut : 2 pcs.
: M8 x 16 mm bolt and washer : 4 pcs.
Tightening torque (M8)
22.5 - 26.5 N・m
(230 - 270 kg・cm)
(16.5 - 19.5 ft・lb.)
(3) Finally, tighten the self lock nut etc. fully,
according to the following priority.
1 M8 self lock nut : 2 pcs.
2 M8 x 16 mm bolt and washer : 2 pcs.
3 M8 x 16 mm bolt and washer : 2 pcs.
4 M8 x 18 mm flange bolt : 2 pcs.
2 M8 x 16 BOLT AND
WASHER AY : 2 pcs.
Tightening torque (M6)
8.8 - 10.8 N・m
(90 - 110 kg・cm)
(6.5 - 8.0 ft・lb.)
GASKET
(MUFFLER)
MUFFLER
A
SPACER
(EXHAUST)
1 M8 SELF LOCK
NUT : 2 pcs.
MUFFLER BRACKET
HEAD COVER
M8 WASHER : 2 pcs.
3 M8 x 16 BOLT AND
WASHER AY : 2 pcs.
4 M6 x 18 FLANGE
BOLT : 2 pcs.
A
Fig. 5-41b
- 44 -
5-4-18 BLOWER HOUSING AND RECOIL STARTER
(1) Attach blower housing to crankcase. Tighten
five flange bolts.
M6 x 12 mm flange bolt : 5 pcs.
Insert the high tension cord from the ignition
coil into the notch of the blower housing so as
not to pinch the cord.
(2) Install recoil starter to blower housing.
M6 x 8 mm flange bolt : 4 pcs.
Note:
Be careful of pulling direction of starter
rope.
5-4-19 STOP SWITCH
(1) Install stop switch to blower housing.
CLAMP
(2) Connect wires referring to the wiring diagram.
STOP SWITCH
STOP SWITCH WIRE
- End of the reassembly -
Model: EH12-2D
Fig. 5-42
- 45 -
5-5 BREAK-IN OPERATION
A new engine or an engine that has been completely overhauled by being fitted with a new piston, rings,
valves and connecting rod should be thoroughly RUN-IN before being put back into service.
Good bearing surfaces and running clearances between the various parts can only be established by
operating the engine under reduced speed and loads for a short period of time.
While the engine is being tested, check for oil leaks.
Make final carburetor adjustment and regulate the engine operating speed.
Step
Load
Engine Speed
Time
Step 1
No Load
2,500 rpm
10 min.
Step 2
No Load
3,000 rpm
10 min.
Step 3
No Load
3,600 rpm
10 min.
3,600 rpm
30 min.
3,600 rpm
60 min.
EH09D
0.7 kW (1.0 HP)
EH12-2D
1.0 kW (1.4 HP)
EH09D
1.4 kW (1.9 HP)
EH12-2D
2.1 kW (2.8 HP)
Step 4
Step 5
Table. 5-2
6. MAGNETO
6-1 OPERATION AND FUNCTION
The ignition system of the EH09D and EH12-2D is a breakerless flywheel magneto with an automatic
advancing system.
Being different from the breaker point type ignition system, this system is completely free from such
troubles as starting-up failure due to dirty, burnt or corroded point surface.
The electronic automatic advancing ensures extremely easy starts and stable high performance at operating speed by advancing the ignition timing to the most suitable point.
6-2 BASIC THEORY
(1) Revolution of the flywheel generates electricity on the primary side of the ignition coil, and the base
current I1 flows to the power transistor.
Current I1 turns the power transistor “ON” and the electric current I2 flows.
- 46 -
(2) At lower engine revolution, when the flywheel reached the ignition point the low speed ignition timing
control circuit operates to run the base current I3 to turn the signal transistor A “ON” allowing the
current I1 to bypass as current I4.
At this moment the power transistor turns “OFF” and the current I2 is abruptly shut off resulting in the
high voltage generated in the secondary coil which produces sparks at the spark plug.
(3) At higher engine revolution, the advancing control circuit operates at the ignition timing to run the
base current I5 to turn the signal transistor B “ON” allowing the current I1 to bypass as current I6.
At this moment the power transistor turns “OFF” and the current I2 is abruptly shut off resulting in the
high voltage generated in the secondary coil which produces sparks at the spark plug.
I4
Primary Coil
Power Transistor
Spark plug
I5
Secondary Coil
Automatic
Advancing
Control
Circuit
I1
Signal Transistor B
I3
I2
I6
Fig. 6-1a
ELECTRONIC ADVANCING FLYWHEEL
MAGNETO SYSTEM
(B.T.D.C.)
(EH12-2D)
23°
IGNITION TIMING
Low Speed
Ignition
Timing
Control Circuit
Signal Transistor A
Resister
The operating timing of the advancing control circuit advances in accordance with the increase of
engine speed resulting in the advancing of ignition timing as shown in Fig. 6-1(b).
STEP ADVANCING
(EH09D)
18°
15°
500
1000
2000
ENGINE REVOLUTION
Fig. 6-1b
- 47 -
3000 (r.p.m.)
6-3 WIRING DIAGRAM
● STANDARD
Fig. 6-2
- 48 -
7. AUTOMATIC DECOMPRESSION SYSTEM
EH09D and EH12-2D engines employ an automatic decompression system as a standard feature. This
enables easy starting of the engine, with lighter recoil pull.
The automatic decompression system releases the compression of the engine by lifting up the exhaust
valve at cranking speeds. The following is the explanation of how the system works.
At the end of the compression process, the release lever lifts up the tappet which in turns opens up the
exhaust valve slightly to release the compression. The release lever has a flyweight on its end and
another end of the lever is a crescent cam.
When the engine is cranked, the crescent cam projects above the cam profile and lifts up the tappet
because the gravity force on the weight is larger than the centrifugal force on the weight.
TAPPET
FLYWEIGHT
RELEASE LEVER
CRESCENT CAM
N
EXHAUST CAM
IO
T
TA
EXHAUST CAM
RO
CAMSHAFT
Fig. 7-1
When the cranking speed reaches a specified r.p.m., the crescent cam is retracted under the cam profile
because the centrifugal force applied to the flyweight becomes larger than the force of gravity on the
weight and thus it is shifted to the position shown in the illustration below.
FLYWEIGHT
TAPPET
RELEASE LEVER
CRESCENT CAM
N
EXHAUST CAM
IO
RO
T
TA
EXHAUST CAM
CAMSHAFT
Fig. 7-2
- 49 -
8a. FLOAT TYPE CARBURETOR (EH09D)
8a-1 OPERATION AND CONSTRUCTION
8a-1-1 FLOAT SYSTEM
The float chamber is located below the carburetor body and, with a float and a needle valve,
maintains a constant fuel level during engine operation.
FUEL
The fuel flows from the fuel tank into the float
chamber through the needle valve. When the fuel
rises to a specific level, the float rises, and when
its buoyancy and fuel pressure are balanced, the
needle valve closes to shut off the fuel, thereby
keeping the fuel at the predetermined level.
NEEDLE VALVE
FLOAT
Fig. 8-1
PILOT JET
BY-PASS
PILOT AIR JET
;;
;;;
;;
PILOT OUTLET
MAIN NOZZLE
CHOKE
AIR
INTAKE
;
FLOAT
MAIN AIR JET
MAIN JET
Fig. 8-2
- 50 -
8a-1-2 PILOT SYSTEM
The pilot system feeds the fuel to the engine during idling and low-speed operation. The fuel is fed
through the main jet to the pilot jet, where it is metered, and mixed with the air metered by the pilot air jet.
The fuel-air mixture is fed to the engine through the pilot outlet and the bypass. At idling speed, the fuel
is mainly fed from the pilot outlet.
8a-1-3 MAIN SYSTEM
The main system feeds the fuel to the engine at medium and high-speed operation. The fuel is metered
by the main jet and fed to the main nozzle. The air metered by the main air jet is mixed with the fuel
through the bleed holes in the main nozzle, and the mixture is atomized out of the main bore. It is mixed
again with the air taken through the air cleaner into an optimum fuel-air mixture, which is supplied to the
engine.
8a-1-4 CHOKE
The choke is used for easy starting when the engine is cold. When the starter is operated with a closed
choke, the negative pressure applied to the main nozzle increases and draws more fuel ; thus richening
the mixture and making starting the engine easier.
8a-2 DISASSEMBLY AND REASSEMBLY
Apart from mechanical failures, most of carburetor troubles are caused by an incorrect mixing
ratio, which may arise mainly due to a clogged up
air or fuel passage in jets, or fuel level variations.
In order to assure proper flow of air and fuel, the
carburetor must be kept clean at all times. The
carburetor disassembly and reassembly procedures are as follows.
1
2
3
4
5
9
8
7
6
13
12
8a-2-1 THROTTLE SYSTEM
(1) The spring r can be taken out by removing
the throttle stop screw t.
(2) Remove the philips screw q and throttle valve
w, and pull out the throttle shaft e.
16
19
18
15
17
*Be careful not to damage throttle valve rim.
11
14
10
Fig. 8-3
- 51 -
8a-2-2 CHOKE SYSTEM
(1) Remove the philips screws y and choke valve u, and pull out the choke shaft i.
(2) When reassembling the choke shaft, make sure that the cutout in the choke valve faces the pilot air
jet.
8a-2-3 PILOT SYSTEM
(1) Remove the pilot jet o, using correct tool to avoid damage to it.
(2) Reassembly
Tighten the pilot jet securely. Otherwise, the fuel may leak, causing engine malfunction.
8a-2-4 MAIN SYSTEM
(1) Remove the bolt !0 and take out float chamber body !1.
(2) Remove the main jet !3 and guide holder from the body !2 .
(3) Reassembly
a) Fasten the main jet securely to the body. Otherwise, the fuel may become too rich and cause
engine malfunction.
b) The bolt !0 tightening torque is 90 kg-cm. Be sure to set the gasket !5 and washer !4 for chamber
!1.
8a-2-5 FLOAT SYSTEM
(1) Pull out the float pin !6 and remove the float !7 and then remove the clip !8 and needle valve !9. If the
needle valve needs to be replaced, replace it with rubber needle.
CAUTION :
When cleaning the jets, use neither a drill nor a wire (because of possible damage of the
orifice which will adversely affect fuel flow). Be sure to use compressed air to blow them
clean.
(2) When removing the needle valve and float, gently tap the reverse side of the float pin !6 using a rod
more slender than the float pin and remove, since the float pin is pressed into the carburetor body.
- 52 -
8b. FLOAT TYPE CARBURETOR (EH12-2D)
8b-1 OPERATION AND CONSTRUCTION
8b-1-1 FLOAT SYSTEM
The float chamber is located below the carburetor body and, with a float and a needle valve,
maintains a constant fuel level during engine operation.
FUEL
The fuel flows from the fuel tank into the float
chamber through the needle valve. When the fuel
rises to a specific level, the float rises, and when
its buoyancy and fuel pressure are balanced, the
needle valve closes to shut off the fuel, thereby
keeping the fuel at the predetermined level.
NEEDLE VALVE
FLOAT
Fig. 8-4
PILOT JET
PILOT OUTLET
BY-PASS
PILOT AIR JET
MAIN NOZZLE
AIR
INTAKE
CHOKE
FLOAT
MAIN AIR JET
MAIN JET
Fig. 8-5
- 53 -
8b-1-2 PILOT SYSTEM
The pilot system feeds the fuel to the engine during idling and low-speed operation.
The fuel is fed through the main jet to the pilot jet, where it is metered, and mixed with the air metered by
the pilot air jet. The fuel-air mixture is fed to the engine through the pilot outlet and the bypass. At idling
speed, the fuel is mainly fed from the pilot outlet.
8b-1-3 MAIN SYSTEM
The main system feeds the fuel to the engine at medium and high-speed operation. The fuel is metered
by the main jet and fed to the main nozzle. The air metered by the main air jet is mixed with the fuel
through the bleed holes in the main nozzle, and the mixture is atomized out of the main bore. It is mixed
again with the air taken through the air cleaner into an optimum fuel-air mixture, which is supplied to the
engine.
8b-1-4 CHOKE
The choke is used for easy starting when the engine is cold. When the starter is operated with a closed
choke, the negative pressure applied to the main nozzle increases and draws more fuel ; thus richening
the mixture and making starting the engine easier.
8b-2 DISASSEMBLY AND REASSEMBLY
1
Apart from mechanical failures, most of carburetor troubles are caused by an incorrect mixing
ratio, which may arise mainly due to a clogged up
air or fuel passage in jets, or fuel level variations.
In order to assure proper flow of air and fuel, the
carburetor must be kept clean at all times. The
carburetor disassembly and reassembly procedures are as follows.
8b-2-1 THROTTLE SYSTEM
2
3
7
6
8
11
9
4
14
5
10
20
15
(1) Remove the philips screw q and throttle valve
w, and pull out the throttle shaft e.
(2) The spring r can be taken out by removing
the throttle stop screw t.
23
17
22
16
19
21
*Be careful not to damage throttle valve rim.
13
18
12
Fig. 8-6
- 54 -
8b-2-2 CHOKE SYSTEM
(1) Remove the philips screws y and choke valve u, and pull out the choke shaft i.
(2) When reassembling the choke shaft, make sure that the cutout in the choke valve faces the pilot air
jet. Meanwhile, when reassembling set the rings o and !0 at the right position.
8b-2-3 PILOT SYSTEM
(1) Remove the pilot jet !1, using correct tool to avoid damage to it.
(2) Reassembly
Tighten the pilot jet securely. Otherwise, the fuel may leak, causing engine malfunction.
8b-2-4 MAIN SYSTEM
(1) Remove the bolt !2 and take out float chamber body !3.
(2) Remove the main jet !6 and guide holder !7 from the body !4 . And then remove the main nozzle !5.
(3) Reassembly
a) Fasten the main jet and main nozzle securely to the body. Otherwise, the fuel may become too rich
and cause engine malfunction.
b) The bolt !2 tightening torque is 70 kg-cm. Be sure to set the gasket !9 and washer !8 for chamber
!3.
8b-2-5 FLOAT SYSTEM
(1) Pull out the float pin @0 and remove the float @1 and then remove the clip @2 and needle valve @3. If the
needle valve needs to be replaced, replace it with rubber needle.
CAUTION :
When cleaning the jets, use neither a drill nor a wire (because of possible damage of the
orifice which will adversely affect fuel flow). Be sure to use compressed air to blow them
clean.
(2) When removing the needle valve and float, gently tap the reverse side of the float pin @0 using a rod
more slender than the float pin and remove, since the float pin is pressed into the carburetor body.
- 55 -
8c. DIAPHRAGM TYPE CARBURETOR (OPTION)
8c-1 OPERATION AND CONSTRUCTION
4
3
1
8
;;
;;
2
5
6
19
20
15
18
14
17
16
7
13
11
10
12
9
Fig. 8-7
1. ENGINE IMPULSE
The alternating action of the positive pressure and negative pressure inside the engine crankcase operates the fuel pump diaphragm.
2. FUEL PUMP DIAPHRAGM
The fuel pump diaphragm undulates in response to the engine impulse and as a result of that movement
it feeds the fuel through the fuel pump valve.
3. FUEL INLET
The fuel inlet is the opening through which fuel is sucked from the fuel tank.
4. INLET VALVE
The inlet valve opens when the diaphragm is submitted to the action of a negative pressure in response
to the movement of the pump diaphragm and the inlet valve shuts when it is submitted to a positive
pressure.
5. OUTLET VALVE
Oppositely to the inlet valve, the outlet valve shuts when it is submitted to the action of a negative
pressure and opens when submitted to a positive pressure.
- 56 -
6. INLET SCREEN
The inlet screen filters the fuel that is sucked from the fuel tank to the carburetor.
7. INLET NEEDLE VALVE
The inlet needle valve controls the fuel that is fed from the fuel pump to the metering chamber.
8. THROTTLE VALVE
The throttle valve controls the volume of air sucked into the engine, thereby changing the engine speed.
9. AIR VENT HOLE
The air vent hole is open to the atmosphere, with the purpose of allowing smooth operation of the
metering diaphragm.
10. METERING DIAPHRAGM
The metering diaphragm has the function of operating the metering lever, which is pulled up by the
variations in the negative pressure of the engine.
11. METERING LEVER
The metering lever has the function of opening/shutting the inlet needle valve by transmitting the movements of the metering diaphragm to that valve.
12. METERING LEVER SPRING
The metering lever spring has the function of pushing up the metering lever, thereby shutting the needle
valve when the engine is stopped and when the metering chamber is full of fuel.
13. METERING CHAMBER
The metering chamber is the fuel storage compartment that has the function of supplying fuel to the
nozzle holes and other parts.
14. FIRST IDLE HOLE
The first idle hole is the only fuel supply hole that is available when the engine is idling.
15. SECOND AND THIRD IDLE HOLES
The second and the third idle holes have the function of supplying fuel when the throttle is at an intermediate opening state between the idling state and the fully open state.
- 57 -
16. IDLE NEEDLE
The idle needle has the function of controlling the fuel when the engine is at idling speeds and when the
throttle is at a low speed position.
17. HIGH SPEED NEEDLE
The high speed needle has the function of controlling the fuel when the engine is operating at high speed
and when the throttle is at a high speed position.
18. MAIN NOZZLE
The main nozzle is the hole through which fuel is ejected when the engine is operating at high speed and
when the throttle is at a high speed position.
19. VENTURI
The venturi has the function of increasing the air flow at the nozzle section, thereby improving the atomization of the fuel.
20. CHOKE VALVE
The choke valve has the function of shutting the suction of air when the engine is started at cold state,
thereby securing the temporary supply of a rich fuel/air mixture.
- 58 -
8c-2 DISASSEMBLY PROCEDURE
Prior do disassembling the carburetor, make sure
to wash it with clean gasoline, washing oil or the
like.
14
13
(1) Loosen the pump cover screw !4 and remove
the screw and the pump cover !3.
(2) Remove the pump gasket !2 and the diaphragm
!1.
12
(3) Next, place the carburetor with the metering
side up and remove the metering cover screws
i (4 screws).
11
15
1
20
10
9
(4) Remove the metering cover u, the diaphragm
ass'y y and the gasket t.
(5) Loosen the metering lever pin screw !7 and
remove the lever r, pin !8, spring e, needle
valve w, etc.
(6) Remove the high-speed needle o and the
idle needle !0.
19
16
3
2
4
18
17
5
8c-3 INSPECTION PROCEDURE
6
(1) Wash the carburetor body with gasoline or the
like and blow it with compressed air.
However, make sure not to blow compressed
air into the check valve unit of the carburetor
equipped with primer pump.
(2) Check the gaskets for any deformation and/or
damage. If a gasket is deformed or damaged,
make sure to replace it with a new one.
7
8
Fig. 8-8
(3) Make sure that the pump diaphragm !1 is not
damaged and make sure that the inlet valve
and outlet valve are flat and not bent.
(4) Make sure that the metering diaphragm y is not damaged and that the plate is not bent.
(5) Check the throttle shaft !9 and the choke shaft @0 for smooth operation.
(6) Check the inlet screen q for sticking of foreign matter. If there is any particle of foreign matter stuck
on the inlet screen, wash it and blow it out with compressed air.
(7) Check the inlet needle valve w for abnormal wearing. If the inlet needle valve is worn, change it with
a new one.
- 59 -
8c-4 REASSEMBLY PROCEDURE
(1) Mount the inlet screen q on the body.
(2) Mount the inlet needle valve w, metering lever spring e, metering lever r and other related parts.
After mounting these parts, adjust the metering lever r position at the specified height. Be particularly careful when carrying out this adjustment, because the metering lever height depends on the
model.
(3) Next, mount the metering gasket t , metering diaphragm y and cover u in this order and then
tighten the four cover screws i.
(4) Mount the high-speed needle o and the idle needle !0, turn them gently clockwise to the fully shut
position and then adjust them to the specified opening by returning them counterclockwise from that
position. Be particularly careful when carrying out this adjustment, because the opening depends on
the model, both for the H and L positions.
(5) Next, mount the pump diaphragm !1, pump gasket !2 and pump cover !3 in this order and then
tighten the pump cover screw !4.
Refer to the figure at the Fig. 8-8 for the procedure for mounting the parts of the carburetor.
By the way, when the idle needle !0 and the high-speed needle o require a considerable amount of
adjustment and when large amounts of foreign matter is stuck on the inlet screen q when the carburetor is disassembled, be sure to clean the interior of the fuel tank and change the tank filter.
- 60 -
8c-5 DIAPHRAGM CARBURETOR ADJUSTMENT METHOD
In the first place, set the idle needle !0 and the high-speed needle o at their standard return openings
and then carry out the adjustment according to the following steps of procedure.
8c-5-1 IDLING ADJUSTMENT
(1) Start the engine and then carry out the adjustment of the idle adjust screw !5 for the engine to operate
at a speed slightly lower than the speed at which the clutch engages.
(2) Turn the idle needle !0 clockwise/counterclockwise so as to find the position where the engine operates most smoothly.
(3) By means of the idle adjust screw !5, adjust the engine at a speed approximately 500 r.p.m. higher than
the specified idling speed.
(4) Next, turn the idle needle !0 counterclockwise for the engine to operate at the specified idling speed.
8c-5-2 HIGH-SPEED ADJUSTMENT
(1) Set the throttle valve !6 at the fully open state and check whether the engine rotates at the speed
specified by the manufacturer.
1) If the engine speed is too high, turn the high-speed needle o counterclockwise so as to adjust the
engine revolution speed at the specified value.
2) If the engine speed is too low, turn the high-speed needle o clockwise so as to adjust the engine
revolution speed at the specified value.
*The idle needle !0 and the high-speed needle o are set at the correct adjustments through the execution of
the steps of procedure described above.
At that time, the adjustment is regarded as correct and normal if the needle return opening is within 1/2 of
the standard return opening.
- 61 -
9. STARTING SYSTEM
9-1 RECOIL STARTER
Tools required: Driver, Pinchers (Pliers) and Protective Glasses
WARNING :
Before starting the disassembly, make sure to wear the protective glasses.
9-1-1 Disassembly Steps
(1) Setting off the spring power
-1 : Hold the starter knob and extract the starter
rope.
-2 : Extract the rope fully and hold the rope so
that the knob of the rope in the reel makes
a direct line with the rope guide.
-3 : Push and hold the reel with the thumbs of
both hands firmly so that the rope will not
be wound back. (Fig. 9-1)
-4 : Pull off the knot of the rope out of the reel,
unfasten the knot and pull it off to the direction of the starter knob. (2 persons required)
Fig. 9-1
-5 : By controlling the reel with the thumbs of
both hands, unwind the rope gently until
the rotation of the reel Stops.
WARNING :
The spring power is at its most when the rope is fully extracted. Therefore, do not abruptly
put off your hand nor loosen the pressure of your finger unintentionally.
- 62 -
(2) Setting the attachments off (Fig. 9-2)
SET SCREW
-1 : Fix the case and loosen the set-screw.
RATCHET
GUIDE
-2 : Put off the set-screw, the ratchet guide,
the friction spring and the ratchet in the
same order from above.
FRICTION
SPRING
(3) Setting the reel off (Fig. 9-2)
RATCHET
-1 : Push the reel lightly so that it will not float
up. Move the reel clockwise and counterclockwise about a quarter circle for several times until it moves smoothly.
REEL
-2 : Pull up the reel gradually and slowly and
put it off from the case.
-3 : In case the spring in the reel is close to
pop up, redo the steps of (3)-1 and (3)-2
again.
WARNING :
STARTER
CASE
Fig. 9-2
Do not drop or shake the reel and put it
on a level table because there is a spring
set in the disassembled reel.
Disassembly is complete.
WARNING :
Before starting the assembly, make sure to wear the protective glasses.
9-1-2 Assembly Steps
(1) Setting the reel into the case.
GREASE PASTING
-1 : Paste grease on the case. (Fig. 9-3)
-2 : Adjust the position of the inner end of the
spring, which is set in the reel. (Fig. 9-4)
-3 : Hold the reel so that the shaft/hook part
and the inner-end of the spring are hooked
together. Drop the reel gently from above
into the case.
-4 : Move the reel slightly counterclockwise and
make sure the spring is hooked.
SHAFT / HOOK PARTS
Fig. 9-3
THE POSITION THE END TOUCHES
THE RIB OF THE BEARING
Fig. 9-4
- 63 -
(2) Setting the attachments
-1: Set the ratchet into the reel. (Fig. 9-5)
THE RATCHET IS KEPT AT CLOSE-POSITION
Fig. 9-5
-2: Holding the ratchet, set the ratchet-guide
subassembly. (Fig. 9-6)
SET SCREW
RATCHET
GUIDE
FRICTION
SPRING
RATCHET GUIDE SUB-ASSEMBLY
Fig. 9-6
(3) Tightening the set-screw.
A
FR BOU
O T
M 2
TH 00
E mm
RE
EL
-1 : Push the ratchet-guide lightly by hand so
that the ratchet guide won't move and
tighten the set-screw.
(4) Storing the spring-power.
-1 : Hold the case tight and using both hands,
wind up the reel counterclockwise 6 times.
-2 : Set the reel to keep the position, whereby
the rope hole of the reel and the rope guide
make a direct line. (Fig. 9-7)
Fig. 9-7
WARNING :
The spring power is at its most when the reel is being wound. Therefore, do not abruptly
put off your hand nor loosen the pressure of Your finger unintentionally.
- 64 -
(5) Setting the rope. (2 persons required)
-1 : Set the end of the rope through the rope
guide and the rope hole of the reel and pull
the end about 20 cm out of the reel.
(Fig. 9-7)
ABOUT
20mm
-2 : Fasten the end of the rope.
Fig. 9-8
-3 : Put the rope into the reel, whereby make
sure that the rope will not float up.
(Fig. 9-9)
-4 : Hold the rope firmly with one hand at the
position about 50 cm from the rope guide
and keep the rope slightly pulled so that
the rope will not be wound in.
-5 : Take your hand off the reel gently and release the rope slowly checking the winding power of the spring until the knob
reaches the rope guide.
Fig. 9-9
Assembly is complete.
(6) Test the operation of the recoil starter to see if the rope recoils satisfactorily and the ratchets extend
and retract properly. Mount the recoil starter to the engine.
(7) If the spring escapes from the reel when disassembling the recoil, hook the outer end of the spring
onto the notch of the reel and rewind the spring into the housing.
(8) Lubricate the rotating parts, sliding parts and spring with heat resistant grease before reassembling
the recoil and prior to long term storage.
- 65 -
10. TROUBLESHOOTING
The following three conditions must be fulfilled for satisfactory engine start.
1. The cylinder filled with a proper fuel-air mixture.
2. Good compression in the cylinder.
3. Good spark, properly timed, to ignite the mixture.
The engine cannot be started unless these three conditions are met. There are also other factors which
make engine start difficult, e. g., a heavy load on the engine when it is about to start at low speed, and a
high back pressure due to a long exhaust pipe.
The most common causes of engine troubles are given below :
10-1 STARTING DIFFICULTIES
10-1-1 FUEL SYSTEM
(1) No gasoline in the fuel tank, or the fuel cock closed.
(2) The carburetor is not choked sufficiently especially when the engine is cold.
(3) Water, dust or gum in the gasoline interfering with the fuel flow to the carburetor.
(4) Inferior grade gasoline or poor quality gasoline not vaporized enough to produce the correct fuel-air
mixture.
(5) The carburetor needle valve is held open by dirt or gum. This trouble can be detected as the fuel flows
out of the carburetor when the engine is idling. (Overflow)
This trouble may be remedied by lightly tapping the float chamber with the grip of a screwdriver or the
like.
(6) If the carburetor overflows, excessive fuel runs into the cylinder when starting the engine, making the
fuel-air mixture too rich to burn. If this happens, remove the spark plug, and turn the starting pulley a
few turns in order to let the rich fuel-air mixture out of the spark plug hole and into the atmosphere.
Keep the choke valve open during this operation.
Dry the spark plug well, screw it into place, and try to start again.
10-1-2 COMPRESSION SYSTEM
If starting difficulties and loss of power are not due to the fuel system or ignition system, the followings
must be checked for possible lack of compression.
(1) Engine inside is completely dried up because of a long period of storage.
(2) Loose or broken spark plug. This causes a hissing noise made by air/fuel mixture running out of
cylinder in compression stroke during cranking.
(3) Damaged head gasket or loose cylinder head. A similar hissing noise is produced during compression stroke.
- 66 -
(4) Incorrect Valve clearance
If the correct compression is not obtained even after remedying the above, disassemble the engine
and check further as follows :
a) Valve stuck open due to carbon or gum on the valve stem.
b) If the piston rings are stuck on the piston, remove the piston and connecting rod from the engine.
Clean or replace the parts.
10-1-3 IGNITION SYSTEM
Check the followings for lack of sparks.
(1) Wires of the ignition coil, spark plug or contact breaker disconnected.
(2) Ignition coil damaged and shorted.
(3) Spark plug cable wet or soaked with oil.
(4) Spark plug dirty or wet.
(5) Spark plug electrode gap incorrect.
(6) Spark plug electrodes are connected or bridged.
(7) Incorrect spark timing.
(8) Proper connection of all wires.
10-2 ENGINE MISFIRES
(1) Incorrect spark plug electrode gap. Adjust it to anywhere between 0.7 and 0.8 mm.
(2) Ignition cable worn and leaking.
(3) Sparks weak.
(4) Ignition wire connections loose.
(5) Water in gasoline.
(6) Insufficient compression.
10-3 ENGINE STOPS
(1) Fuel tank empty. Water, dirt, gum, etc. in gasoline.
(2) Vapor lock, i. e., gasoline evaporating in the fuel lines due to overheating of the engine.
(3) Vapor lock in the fuel lines or carburetor due to the use of too volatile (winter) gas in the hot season.
(4) Air vent hole in the fuel tank cap plugged.
(5) Bearing parts seized due to lack of oil.
(6) Magneto or ignition coil faulty.
- 67 -
10-4 ENGINE OVERHEATS
(1) Crankcase oil level low. Add oil immediately.
(2) Spark timing incorrect.
(3) Low grade gasoline is used, or engine is overloaded.
(4) Cooling air circulation restricted.
(5) Cooling air path misdirected causing loss of cooling efficiency.
(6) Cylinder head cooling fins clogged up with dirt.
(7) Engine operated in an enclosed space without sufficient cooling air.
(8) Exhaust gas discharge restricted, or carbon deposits in the combustion chamber.
(9) Engine running on low-octane gasoline detonates due to heavy load at low speed.
10-5 ENGINE KNOCKS
(1) Poor quality gasoline.
(2) Engine operating under heavy load at low speed.
(3) Carbon or lead deposits in the cylinder head.
(4) Spark timing incorrect.
(5) Loose connecting rod bearing due to wear.
(6) Loose piston pin due to wear.
(7) See causes of engine overheat.
10-6 ENGINE BACKFIRES THROUGH CARBURETOR
(1) Water or dirt in gasoline, or low-grade gasoline.
(2) Intake valve stuck.
(3) Valves overheated, or hot carbon particles in the combustion chamber.
(4) Engine cold.
- 68 -
11. INSTALLATION
Engine life, ease of maintenance and inspection, frequency of checks and repairs, and operating cost all
depend on the way in which the engine is installed. Review the following instructions carefully for installing the engine.
11-1 INSTALLING
When mounting the engine, carefully examine its position, the method of connecting it to a machine, the
foundation, and the method of supporting the engine.
When determining its mounting position, in particular, make sure that gasoline and oil can easily be
supplied and checked, the spark plug can easily be checked, the air cleaner can easily be serviced, and
that the oil can easily be discharged.
11-2 VENTILATION
Fresh air is necessary for cooling the engine and burning the fuel.
In the case the engine is operated under a hood or in a small room, temperature rise in the engine room
can cause vapor lock, oil deterioration, increased oil consumption, loss of power, piston seizure, shorter
engine life, etc., making it impossible to operate the engine properly. It is necessary, therefore, to provide
a duct or baffle to guide cooling air to the engine to prevent recirculation of the hot air used for engine
cooling, and temperature rise of the machine. Keep the engine room temperature below 50°
C even in the
hottest period of the year.
11-3 EXHAUST GAS DISCHARGE
Exhaust gas is noxious. When operating the engine indoors, be sure to discharge the exhaust gas
outdoors. If a long exhaust pipe is used in such a case, the internal resistance increases causing loss of
engine power. Thus pipe inside diameter must be increased in proportion to exhaust pipe length.
Exhaust pipe : Less than 3 m long, pipe inside diameter 30 mm ,
Less than 5 m long, pipe inside diameter 33 mm.
11-4 POWER TRANSMISSION TO DRIVEN MACHINES
11-4-1 BELT DRIVE
Take the following notes into consideration.
* V-belts are preferable to flat belts.
* The driving shaft of the engine must be parallel to the driven shaft of the machine.
* The driving pulley of the engine must be in line with the driven pulley of the machine.
* Install the engine pulley as close to the engine as possible.
* If possible, span the belt horizontally.
* Disengage the load when starting the engine.
If no clutch is used, use a belt tension pulley or the like.
11-4-2 FLEXIBLE COUPLING
When using a flexible coupling, run out and misalignment between the driven shaft and engine shaft
must be minimized. Run out and misalignment tolerance are specified by the coupling manufacturer.
- 69 -
12. SERVICE DATA
“STD” in the following table is the parts dimension from the brand new engine or the spare parts.
Whereas, “Limit” shows the maximum allowance for the parts to be used on the engine.
If the measurement exceeds beyond the “Limit”, the part needs to be replaced and/or repaired.
12-1 CLEARANCE DATA AND LIMITS
Unit : mm (in.)
EH09D
ITEM
CYLINDER HEAD
* Flatness
STD
Limit
LESS THAN
0.05
(0.002)
0.1
(0.004)
0.8 - 1.1
(0.0315 - 0.0433)
2.0
(0.079)
5.500 - 5.518
(0.2165 - 0.2172)
5.65
(0.2224)
* Valve seat contact width
IN. EX.
* Valve guide inside dia.
Unit : mm (in.)
EH12-2D
ITEM
STD
Limit
LESS THAN
0.05
(0.002)
0.1
(0.004)
0.7 - 1.0
(0.028 - 0.039)
2.0
(0.079)
5.500 - 5.518
(0.2165 - 0.2172)
5.65
(0.2224)
CYLINDER HEAD
* Flatness
* Valve seat contact width
IN. EX.
* Valve guide inside dia.
- 70 -
Unit : mm (in.)
EH09D
EH12-2D
ITEM
STD
CYLINDER
* Inside dia.
Limit
To be rebored
when the
difference
between max.
and min.
of diameter
reached to 0.1
(0.004).
STD
Limit
To be rebored
when the
difference
between max.
and min.
of diameter
reached to 0.1
(0.004).
STD
51.0 - 51.019
(2.008 - 2.009)
1 st
reboring
51.250 - 51.269
(2.0177 - 2.0185)
Ditto
60.250 - 60.269
(2.3720 - 2.3728)
Ditto
2 st
reboring
51.500 - 51.519
(2.0276 - 2.0283)
--------------------
60.500 - 60.519
(2.3819 - 2.3826)
--------------------
LESS THAN
0.01
(0.004)
--------------------
LESS THAN
0.01
(0.004)
--------------------
LESS THAN
0.015
(0.0006)
--------------------
LESS THAN
0.015
(0.0006)
--------------------
STD
50.97 - 50.99
(2.0067 - 2.0075)
50.88
(2.0031)
59.96 - 59.98
(2.3606 - 2.3614)
59.87
(2.3571)
1 st o / s
51.22 - 51.24
(2.0165 - 2.0173)
51.13
(2.0123)
60.21 - 60.23
(2.3705 - 2.3713)
60.12
(2.3669)
2nd o / s
51.47 - 51.49
(2.0264 - 2.0272)
51.38
(2.0228)
60.46 - 60.48
(2.3803 - 2.3811)
60.37
(2.3768)
60.000 - 60.019
(2.3622 - 2.3630)
* Roundiness after reboring.
* Cylindricity after reboring.
PISTON
* Piston size (At skirt in thrust
direction)
- 71 -
Unit : mm (in.)
EH09D
EH12-2D
ITEM
PISTON
* Ring groove side clearance
STD
Limit
STD
Limit
Top
0.035 - 0.080
(0.0014 - 0.0031)
0.15
(0.006)
0.030 - 0.075
(0.0012 - 0.0030)
0.15
(0.006)
2nd
0.035 - 0.080
(0.0014 - 0.0031)
0.15
(0.006)
0.030 - 0.075
(0.0012 - 0.0030)
0.15
(0.006)
Oil ring
0.010 - 0.065
(0.0004 - 0.0026)
0.15
(0.006)
0.020 - 0.075
(0.0008 - 0.0030)
0.15
(0.006)
10.991 - 11.009
(0.4327 - 0.4334)
11.035
(0.4344)
12.991 - 13.002
(0.5115 - 0.5119)
13.035
(0.5132)
10.992 - 11.000
(0.4328 - 0.4331)
10.960
(0.4315)
12.992 - 13.000
(0.5115 - 0.5118)
12.960
(0.5102)
0.010 - 0.049
(0.0004 - 0.0019)
0.25
(0.010)
0.015 - 0.074
(0.0006 - 0.0029)
0.25
(0.010)
1.5
(0.0591)
0.2 - 0.4
(0.008 - 0.016)
1.5
(0.0591)
1.5
(0.0591)
0.2 - 0.4
(0.008 - 0.016)
1.5
(0.0591)
* Piston pin hole
* Piston pin outside dia.
* Clearance between piston and
cylinder at skirt
area.
* Piston ring end gap
;;;;;
;;;
Top
2nd
Oil ring
Top
0.15 - 0.35
(0.006 - 0.014)
2nd
0.35 - 0.55
(0.014 - 0.022)
0.05 - 0.25
(0.002 - 0.010)
- 72 -
Unit : mm (in.)
EH09D
EH12-2D
ITEM
STD
Limit
STD
Limit
20.000 - 20.013
(0.7874 - 0.7879)
20.1
(0.7913)
26.000 - 26.013
(1.0236 - 1.0241)
26.1
(1.0276)
0.037 - 0.063
(0.0015 - 0.0025)
0.2
(0.008)
0.020 - 0.046
(0.0008 - 0.0018)
0.2
(0.008)
11.010 - 11.021
(0.4335 - 0.4339)
11.08
(0.4362)
13.010 - 13.021
(0.5122 - 0.5126)
13.08
(0.5150)
0.010 - 0.029
(0.0004 - 0.0011)
0.12
(0.0047)
0.010 - 0.029
(0.0004 - 0.0011)
0.12
(0.0047)
0.1 - 0.7
(0.004 - 0.028)
1.0
(0.040)
0.1 - 0.7
(0.004 - 0.028)
1.0
(0.040)
19.950 - 19.963
(0.7854 - 0.7859)
19.85
(0.7815)
25.967 - 25.980
(1.0223 - 1.0228)
25.85
(1.0177)
CONNECTING ROD
* Big end inside dia.
* Clearance between big end
and crankpin
* Small end inside dia.
* Clearance between small
end and piston pin
* Big end side clearance
CRANKSHAFT
* Crankpin outside dia.
* Journal dia.
D1
D2
D1, D2
19.988 - 19.997
(0.7869 - 0.7873)
- 73 -
D1, D2
24.988 - 24.997
(0.9839 - 0.9841)
Unit : mm (in)
EH09D
EH12-2D
ITEM
STD
Limit
STD
Limit
18.3 - 18.5
(0.720 - 0.728)
18.15
(0.715)
29.6 - 29.8
(1.165 - 1.173)
29.45
(1.159)
D1
9.972 - 9.987
(0.3926 - 0.3932)
9.95
(0.3917)
16.973 - 16.984
(0.6682 - 0.6687)
16.95
(0.6673)
D2
9.972 - 9.987
(0.3926 - 0.3932)
9.95
(0.3917)
14.973 - 14.984
(0.5895 - 0.5899)
14.95
(0.5886)
IN.
5.440 - 5.455
(0.2142 - 0.2148)
5.35
(0.2106)
5.440 - 5.455
(0.2142 - 0.2148)
5.35
(0.2106)
EX.
5.426 - 5.444
(0.2136 - 0.2143)
5.35
(0.2106)
5.426 - 5.444
(0.2136 - 0.2143)
5.35
(0.2106)
IN.
0.045 - 0.078
(0.0018 - 0.0031)
0.3
(0.012)
0.045 - 0.078
(0.0018 - 0.0031)
0.3
(0.012)
EX.
0.056 - 0.092
(0.0022 - 0.0036)
0.3
(0.012)
0.056 - 0.092
(0.0022 - 0.0036)
0.3
(0.012)
IN. / EX.
(cold)
0.07 - 0.13
(0.0028 - 0.0051)
CAMSHAFT
* Cam height (IN. and EX.)
* Journal outside dia.
"D" type
D1
D2
VALVE
* Valve stem outside dia.
*Clearance between valve stem
dia. and valve
guide.
* Valve clearance
- 74 -
0.07 - 0.13
(0.0028 - 0.0051)
Unit : mm (in)
EH09D
EH12-2D
ITEM
STD
Limit
STD
Limit
TAPPET
* Stem outside dia.
7.960 - 7.975
(0.3134 - 0.3140)
7.960 - 7.975
(0.3134 - 0.3140)
8.000 - 8.015
(0.3150 - 0.3156)
8.000 - 8.015
(0.3150 - 0.3156)
0.025 - 0.055
(0.0010 - 0.0022)
0.025 - 0.055
(0.0010 - 0.0022)
* Guide inside dia.
* Tappet guide clearance
VALVE SPRING FREE LENGTH
26.7
(1.05)
--------------------
30.5
(1.2)
--------------------
VALVE SEAT ANGLE (IN. and EX.)
* Valve cutter angle (a)
* Valve contact width (b)
a : 90 °
b : 0.8 - 1.1
(0.031 - 0.043)
b
b
a
- 75 -
2.0
(0.079)
a : 90 °
b : 0.7 - 1.0
(0.028 - 0.039)
2.0
(0.079)
12-2 TORQUE SPECIFICATIONS
Tightening torque
ITEMS
Cylinder head
bolts
Connecting rod
cap bolts
N・
・m
Kg・cm
ft・lb.
(EH09D)
18.6 - 20.6
190 - 210
13.7 - 15.2
(EH12-2D)
23.0 - 26.0
230 - 270
17.0 - 30.0
(EH09D)
5.9 - 7.8
60 - 80
4.3 - 5.7
(EH12-2D)
8.8 - 11.0
90 - 115
6.5 - 8.3
(EH09D)
44.2 - 49.1
450 - 500
32.5 - 36.2
(EH12-2D)
59.0 - 63.0
600 - 650
43.0 - 47.0
(EH09D)
9.8 - 11.8
100 - 120
7.2 - 8.7
(EH12-2D)
9.8 - 11.8
100 - 120
7.2 - 8.7
New one
11.8 - 14.7
120 - 150
8.7 - 10.9
Retightening
22.6 - 24.5
230 - 250
16.6 - 18.1
New one
11.8 - 14.7
120 - 150
8.7 - 10.9
Retightening
22.6 - 26.5
230 - 270
16.6 - 19.5
9.8 - 13.7
100 - 140
7.2 - 10.1
(EH09D)
8.8 - 10.8
90 - 110
6.5 - 8.0
(EH12-2D)
22.5 - 26.5
230 - 270
16.5 - 19.5
Flywheel nut
Main bearing
cover bolts
Spark plug
(EH09D)
Spark plug
(EH12-2D)
Intake pipe (EH12-2D)
Muffler nut
12-3 OIL GRADE CHART
Comparison between oil viscosity and temparature
5W
10W
20W
Single
grade
#20
Specified
Lubricant
Quality
#30
#40
10W-30
Multigrade
10W-40
- 20
-4
- 10
14
0
32
10
50
20
68
30
86
40 °C
104 °F
Use oil classified as SE or higher.
Multi-grade oil tends to increase its consumption at high ambient temperature.
- 76 -
13. MAINTENANCE AND STORAGE
The following maintenance jobs apply when the engine is operated correctly under normal conditions.
The indicated maintenance intervals are by no means guarantees for maintenance free operations during these intervals.
For example, if the engine is operated in extremely dusty conditions, the air cleaner should be cleaned
every day instead of every 50 hours.
13-1 DAILY MAINTENANCE
MAINTENANCE ITEMS
1) Clean away dust and chaff from engine.
REMARKS
Governor linkage is especially sensitive to dust.
2) Check fuel leakage from fuel system. If any,
retighten fasteners or replace necessary parts.
3) Inspect for loose hardware and retighten if
necessary.
Loose bolts and nuts may come off and result in
breakage of other parts.
4) Check oil level and add to full mark.
13-2 INITIAL 20 HRS. MAINTENANCE
MAINTENANCE ITEMS
1) Replace crankcase oil.
REMARKS
To remove sludge from run-in operation.
13-3 EVERY 50 HRS. (10 DAYS) MAINTENANCE
MAINTENANCE ITEMS
1) Change crankcase oil.
REMARKS
Contaminated oil quickens wear.
2) Clean air cleaner.
3) Check and clean spark plug.
If dirty, wash in gasoline or polish with emery paper.
- 77 -
13-4 EVERY 100-200 HRS. (MONTHLY) MAINTENANCE
MAINTENANCE ITEMS
REMARKS
1) Clean fuel filter and fuel tank.
2) Inspect cooling system and remove dirt and chaff.
Remove blower housing and clean up between fins
and housing.
13-5 EVERY 300 HRS. or YEARLY MAINTENANCE
MAINTENANCE ITEMS
REMARKS
1) Check and adjust valve clearance
13-6 EVERY 500-600 HRS. MAINTENANCE
MAINTENANCE ITEMS
REMARKS
Carbon deposits in combustion chamber causes lack
of power.
1) Remove carbon from cylinder head.
2) Disassemble and clean carburetor.
13-7 EVERY 1000 HRS. (YEARLY) MAINTENANCE
MAINTENANCE ITEMS
REMARKS
1) Overhaul engine.
Clean and correct parts.
Replace piston rings and other necessary parts.
2) Replace fuel lines once a year.
Avoid hazards caused by fuel leakage.
13-8 ENGINE STORAGE
(1) Perform the above 13-1 and 13-2 maintenance jobs.
(2) Drain fuel from the fuel tank and carburetor float chamber.
(3) To prevent rust in the cylinder bore, apply oil through the spark plug hole and turn the crankshaft
several turns by hand. Reinstall the plug.
(4) Turn the starting pulley by hand and leave it where the resistance is the heaviest.
(5) Clean outside of the engine with oiled cloth.
(6) Put a plastic cover or the like over the engine and store the engine in dry place.
- 78 -
PRINTED IN THE USA