Subaru ER12 User manual

SERVICE MANUAL
ER12ER12

1. SPECIFICATIONS............................................... 1
2. PERFORMANCE ............................................... 2
3. FEATURES .................................................... 4
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS . . . . . . . . . . . . . . . . 5
5. DISASSEMBLY AND REASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5-1 PREPARATIONS AND PRECAUTIONS                            12
5-2 SPECIAL TOOLS 12
5-3 DISASSEMBLY PROCEDURE  13
5-4 REASSEMBLY PROCEDURE 27
6. ENGINE OIL ................................................... 43
7. LUBRICATION SYSTEM ......................................... 44
8. MAGNETO .................................................... 47
9. WIRING DIAGRAM.............................................. 48
10. AUTOMATIC DECOMPRESSION SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . 49
11. CARBURETOR................................................ 50
12. RECOIL STARTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
13. INSTALLATION................................................ 63
14.TROUBLESHOOTING........................................... 65
15. STANDARD REPAIR TABLES.................................... 68
15-1 STANDARD DIMENSIONS AND LIMITS OF USE                   68
15-2 SERVICE DATA (The following are only for your reference)           73
15-3 TIGHTENING TORQUE 74
15-4 AIR GAP AND CLEARANCE 74
16.MAINTENANCE AND STORAGE .................................. 75
CONTENTS
Section Title Page

- 1 -
1. SPECIFICATIONS
*Specifications are subject to change without notice
Model ER12
Type Air-Cooled, 4-Cycle, Single-Cylinder,
Horizontal P.T.O. Shaft, OHC Gasoline Engine
Bore × Stroke mm (in) 60 × 43 (2.36 × 1.69)
Piston Displacement ml (cuin) 121 (7.38)
Compression Ratio 9.6
Maximum Output kW(HP)/rpm 2.6(3.5)/3600
Maximum Torque
N
・
m / rpm
(kgf
・
m / rpm)
(ft
・
lb / rpm)
7.3/2400
(0.74/2400)
(5.38/2400)
Direction of Rotation Counterclockwise as viewed from the P.T.O. shaft side
Valve Arrangement Overhead cam system
Cooling System Forced air cooling system
Lubrication System Trochoid Pump, Forced and Splash lubrication system
Lubricant Automotive detergent oil - SAE; #20, #30 or 10W-30
API service class; SE or higher (SG, SH or SJ is recommended)
Capacity of Lubricant L (US gal) 0.35 (0.092)
Carburetor Horizontal draft, Float type or Diaphragm type
Fuel Automobile unleaded gasoline
Fuel Supply System Gravity type
Spark Plug NGK CR5HSB
Starting System Recoil starter
Governor Centrifugal flyweight type
Air Cleaner system Semi wet type
Dry Weight kg (lb) 9.9 (21.78)
Dimensions (L x W x H) mm (in) 264 x 288 x 334 (10.39 x 11.34 x 13.15) : Float type Caburetor
264 x 288 x 336 (10.39 x 11.34 x 13.23) : Diaphragm type Caburetor

- 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 engin’s life and fuel consumption
When the engine is installed on a certain equipment, it is recommended that the continuous output required
from the equipment to 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
specific rpm

- 3 -
2-4. PERFORMANCE CURVES
N・m
2000 3000 4000
6.0
7.0
8.0
0.6
0.7
0.8
0.9
1.0
0
2.0
3.0
1.0
0
2.0
3.0
4.0
kW
[HP]
[kgf・m]
r.p.m.REVOLUTION
TORQUE
OUTPUT
RECOMMENDED
HORSEPOWER
RANGE
MAXIMUM
TORQUE
MAXIMUM
HORSEPOWER

- 4 -
3. FEATURES
3-1. DEVELOPED EXCLUSIVELY FOR RAMMER
The new ER12 has been developed exclusively for rammer, which especially requires the engine for high
durability, high power output and superb mountability among many construction machineries
3-2. LIGHTWEIGHT AND COMPACT DESIGN
ER12 has realized lightweight and compact design, while achieving high power output of 26kW (engine
displacement 120cc) that enables to widely fulfill the operating weight of 60 to 80kg-class rammers, the
lightest-in-class* weight of 99kg, and the smallest-in-class* on the length and width
3-3. DESIGNED TO OFFER SUPERIOR MOUNTABILITY
ER12 has been designed to offer superior mountability, which is valued for rammer engine, by the optimal
center of gravity for right-and-Ieft balance
3-4. USER'S SAFETY AS WELL AS USER FRIENDLINESS
ER12 offers several new functions as standard equipment, which has been required to rammer engine for
user's safety as well as user friendliness, such as oil sensor that monitors the oil level not only at starting-up
but also during operation, and automatic shutoff device that stops engine when the rammer rolls over or has
no operation with idling
3-5. EASE OF MAINTENANCE AND ECONOMICAL EFFICIENCY
ER12 has beeh designed in consideration of ease of maintenance and economical efficiency, such as
adopting solid crank case or the newly developed resinous dust-proof air cleaner for realizing ease of
maintenance, realizing longer operational hours without oil-refilling
* FHI researches

- 5 -
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS
4-1 CYLINDER AND CRANKCASE
The cylinder and crankcase are aluminum die-casting
as a single piece A special cast iron cylinder liner is
molded into the aluminum die-casting
The crankcase has a mounting surface on the output
shaft side to which the main bearing cover is attached
And the lib is made for the crankcase room center
cum oil shelter plate, that improvement breather
function and strength up
And inside of the crankcase has large rib for oil shelter
which to inprove the breather function and stiffness
4-2 MAIN BEARING COVER
The main bearing cover is an aluminum die-casting
with heavy-duty structure to endure to install on
rammers, which is mounted on the output shaft side of
the crankcase By removing the main bearing cover,
the inside of the engine can be inspected with ease
Pilots and bosses are machined into the cover for
direct mounting of the engine onto rammers
And it have suction pipe, oil pump, oil filter and oil
pressure switch
4-3 CRANKSHAFT
The crankshaft is forged carbon steel, and the crank
pin is high-frequency inductionhardened
The crank pulley used to drive the timing belt and the
gear used to drive the governor gear are pressed into
the output end of the shaft
4-4 CONNECTING ROD AND PISTON
The connecting rod is a specially heat-treated
aluminum alloy die-casting Its large and small ends
function as bearings The piston is an aluminum alloy
casting with grooves for mounting one compression
ring and one oil ring
JCC

- 6 -
4-7 VALVE ARRANGEMENT
This engine has a belt-driven overhead cam and
overhead valve construction, with a single cam
performing both intake and exhaust operations
4-6 CAMPULLEY
The campulley is made of special nylon They are
constructed as a single piece The campulley is
provided with intake and exhaust cam, and the
decompression release lever is mounted on the
sprocket shaft end side
EXHAUST VALVE INTAKE VALVE
TOP
RING
OIL
RING
1
2
TAPER
THREE-PIECE
CONSTRUCTION
1
2
4-5 PISTON RINGS
The piston rings are made of special cast iron The profile of the top ring is a tapered face
The oil ring is designed for better sealing and less oil consumption, in combination with 3 pieces

- 7 -
4-8 CYLINDER HEAD
The cylinder head is on aluminum die-casting with a
lens-shaped combustion chamber The intake and
exhaust ports are arranged in a cross direction to
improve combustion efficiency
4-11 LUBRICATION SYSTEM
Lubricant (engine oil) is sprayed onto the parts with pressure spray by the trochoid type of oil pump, and
those parts splashes to the parts necessary to be lubricated
The trochoid pump is driven by the crankshaft Lubricant is wholly filtered by the oil pump filter plugged in the
under of the main bearing cover
4-10 COOLING SYSTEM
The engine uses a forced air-cooling system in which a cooling fan on the frywheel, reduce noise and forces
cooling air into the cylinder and cylinder head
Baffle is provided to guide the flow of cooling air
4-9 GOVERNOR SYSTEM
This engine is equipped with a centrifugal flyweight
type governor that makes it possible to operate the
engine at a constant speed, even with load
variations (The governor flyweights are mounted on
a governor gear)
GOVERNOR
GEAR

- 8 -
4-14 CARBURETOR
The engine is equipped with two types of horizontal
draft carburetors, one has a float controlled fuel system
and a fixed main jet, and another is diaphragm type
The carburetors are calibrated carefully for sure
starting, good acceleration, less fuel consumption and
maximum output
For details, refer to page 50, section “11-3 FLOAT
CARBURETOR As details of diaphragm type, refer to
page 53, section “11-4 DIAPHRAGM CARBURETOR”
FLOAT TYPE DIAPHRAGM TYPE
4-12 TIMING BELT
Timing belt system is adopted and designed for
lubricating for the upper portion of cylinder head
The timing belt is engaged between the campulley in
the cylinder head and the crankshaft gear
The pulley and the gear teeth in round shape are
adopted to
enhance the durability and to realize low
noise level
4-13 IGNITION SYSTEM
The ignition system is a pointless flywheel magnet by
a digital control
The magneto consists of a flywheel and ignition coil
with CPU (Central Processing Unit) and CDI
(Capacitor Discharge Ignition) The flywheel is
directly mounted on the crankshaft and the ignition
coil is directly mounted on the crankcase
TIMING BELT
CAMPULLEY
CRANKSHAFT
DRIVEPULLEY
IGNITION COIL
FLYWHEEL
FAN
THICKNESS
GAUGE

- 9 -
4-15 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
AIR CLEANER BASE ELEMENT
URETHANE FOAM
AIR CLEANER COVER
4-16 DECOMPRESSION SYSTEM
The automatic decompression system is mounted on
the campulley It opens the exhaust valve before the
compression top, thereby alleviating the compression
pressure and reducing the force required to pull the
recoil starter
During engine operation, the decompression system
is overpowered by centrifugal force and compression
is fully utilized to produce power
RETURN SPRING
ROCKER ARM
(EXHAUST VALVE SIDE)
EXHAUST VALVE
CAMSHAFT

- 10 -
4-17 SECTIONAL VIEW OF THE ENGINE
Cross sectional view – across the shaft
OIL PRESSURE SWITCH
PISTON
PISTON RING
SUCTION PIPE
PLUG
CYLINDER HEAD
PISTON PIN
OIL PUMP
RECOIL STARTER
FLYWHEEL MAIN BEARING COVER
ADAPTER
CRANKSHAFT
CRANKCASE
SPARK PLUG
P.T.O. SHAFT
IGNITION COIL
SER No. (Stamping)

- 11 -
CRANKSHAFT
SER No. (Stamping)
CONNECTING ROD
TIMING BELT
AIR CLEANER
CARBURETOR
(DIAPHRAGM TYPE)
FLOAT TYPE CARBURETOR
OIL DRAIN PLUG
CRANKCASE
INTAKE VALVE
PISTON RING
OIL GAUGE
STOP SWITCH
ROCKER ARM
GOVERNOR LEVER
GOVERNOR GEAR
SPEED CONTROL LEVER
BREATHER COVER
EXHAUST VALVE
CAMPULLEY
ROCKER COVER
MUFFLER
Cross sectional view – along the shaft

- 12 -
5. DISASSEMBLY AND REASSEMBLY
5-1 PREPARATIONS AND PRECAUTIONS
1) When disassembling the engine, memorize the location of each part so that you can reassemble the engine
correctly If necessary, attach identification tags with the required assembly information to the parts
2) Store groups of parts in separate boxes This will make reassembly easier
3) To prevent parts from being mislaid, keep each group provisionally assembled after removing the parts
from the engine
4) Handle the disassembled parts with the utmost care Clean them with cleaning oil if necessary
5) Use the correct tools in the correct way when disassembling and reassembling the engine
5-2 SPECIAL TOOLS
Tool name Use
Commercially available product Flywheel puller For pulling off the ywheel
Commercially available product Piston ring plier For removing and
installing piston rings
Commercially available product Piston ring
compresser For holding piston rings
Commercially available product Chain wrench For locking the ywheel
FLYWHEEL PULLER PISTON RING PLIER
CHAIN WRENCHPISTON RING COMPRESSER

- 13 -
5-3 DISASSEMBLY PROCEDURE
Step Parts to remove Remarks and procedures Fasteners
1
Drain the engine oill Remove a drain plug (M8 x 12mm) located on both
sides of the case
Take care not to lose the gaskets
*
To discharge oil quickly, remove the oil gauge(M22)
12 mm spanner
2
Air cleaner Remove breather pipe from rocker cover 10mm box spanner
M6 nut:2pcs
GASKET
(Aluminum )
GASKET
(Rubber )
OIL GAUGE
URETHANE FOAM
M6 SELF LOCK NUT : 2pcs.
CLEANER BASE CLEANER COVER
GASKET(INTAKE)
BREATHER PIPE
ELEMENT
M8 DRAIN PLUG : 1pc.
STEP 1
STEP 2

- 14 -
Step Parts to remove Remarks and procedures Fasteners
3
Muffler and Muffler cover (1) Remove the muffler cover from the muffler and
gasket(muffler)
(2) Remove the muffler from the cylinder head
Take care not to lose the gasket
* Take care not to cut your hand with muffler gasket
10mm box spanner or
spanner
13mm box spanner
M6×18mm:3pcs
M6 nut:2pcs
4
Recoil starter Disconnect wire of stop switch first, then remove recoil
starter
10mm box spanner
M6×20mm:2pcs
M6×14mm:1pc
Do Not remove the plug.
RECOIL ASSY
MUFFLER COVER
MUFFLER
STOP SWITCH
M4 SCREW : 2 pcs. M6 x 18
FLANGE BOLT : 3 pcs.
M6 x 20
FLANGE BOLT : 2 pcs.
M6 x 14
FLANGE BOLT : 1 pc. GASKET
(MUFFLER) M6 SELF LOCK NUT : 2pcs.
STEP 3
STEP 4

- 15 -
Step Parts to remove Remarks and procedures Fasteners
5
Carburetor, Insulator Remove the linkage bushing from governor rod
(1) Loosen the and remove the governor lever from
the governor shaft There is no need to remove the
bolt
(2) Remove the governor spring
(3) Remove the governor rod and the rod spring from
the carburetor
Remove the carburetor from the cylinder head
Remove the insulator
10mm box spanner or
spanner
M6×20mm:1pc
M6 Nut:1pc
CYLINDER HEAD GASKET
(INSULATOR)
BLACK
GASKET
(CARBURETOR)
BROWN
GASKET
(INSULATOR)
BLACK
GASKET
(CARBURETOR)
BLACK
CARBURETOR
(DIAPHRAGM TYPE)
INSULATOR 1
SELF LOCK NUT
INTAKE PIPE
INSULATOR 2
STEP 5
A
CYLINDER HEAD
GASKET
(CARBURETOR)
BROWN
CARBURETOR
(FLOAT TYPE)
INSULATOR
STEP 5
A
GASKET
(INSULATOR)
BLACK ROD SPRING
LINKAGE BUSHING
GOVERNOR ROD
GOVERNOR LEVER
GOVERNOR
SPRING
BOLT NUT
DETAIL A

- 16 -
Step Parts to remove Remarks and procedures Fasteners
6
Speed control lever and
Base plate
Remove the speed control lever and base plate from
the crankcase (If necessary)
10mm box spanner
M6×10mm:2pcs
14mm box spanner
Pivot bolt:1pc
M6×20 BOLT
SPEED CONTROL AY
RETURN SPRING
SPACER
GOVERNOR SPRING
GOVERNOR LEVER M6 NUT
STEP 6
SET SCREW (HIGH SPEED)
SET SCREW (LOW SPEED)
PIVOT BOLT Tightening torque : 7.0 - 9.0 N•m
(70 - 90 kgf•cm)
(5.1 - 6.5 ft•lb.)
SPEED CONTROL
LEVER
SWIVEL (NUT) M4 x 0.7
PIVOT BOLT
BASE PLATE
M6×10 FLANGE BOLT:2pcs.
FRICTION WASHER
(NYLON)
NUT
STEP 6