Specifications and dimensions are subject to change without notice.
x
31 1 mm
#20, #30 or 1OW-30
L86C
Starter
kg
(37.5
Ibs.)
(16.10 X 14.65 x 12.24
in.)
-1-
2.
PERFORMANCE
2-1
MAXIMUM OUTPUT
The maximum output
valve fully opened after its initial break-in period when all the moving parts are properly worn in.
Therefore, a new engine may not produce the maximum output in the beginning because the moving
parts are not in a properly worn-in condition.
2-2
MAXIMUM TORQUE
The maximum torque indicates the torque at the output shaft when the engine is producing the maximum
output.
2-3
PERFORMANCE CURVES
EH18V
of
an engine
5.2;
(7.
0
Tn"--r
4.41
(6.0
is
such a standard power
""_~_
as
produced by the engine with
"""
"""_
"""
its
throttle
7.4!
(2.
0
2000 2400 2800 3200
REVOLUTlON
-
3600
r.p.m
"i
-2-
3.
FEATURES
1.
The overhead valve design offers compactness, light weight and ideal combustion characteristics
resulting in more power
2.
The parts
3.
The automatic decompression system offers easy and sure starting.
4.
The muffler and carburetor are located
flow
5.
The oil pump and oil filter provide excellent lubrication regardless of engine posture during
operation.
6.
This engine
7.
The Pro-Poly version engine is covered with a stylishly designed
fuel tank incoroprated into it.
'8.
The Classic Steel version does not have the shroud or combined fuel tank.
4.
GENERAL DESCRIPTION
4-1
CYLINDER AND CRANKCASE
The cylinder and crankcase is single piece aluminum diecasting. The cylinder liner, made of
special cast iron, is molded into the aluminum
casting.
The crankcase has a mounting surface
output shaft side, where the main bearing cover is
attached. (See Fig.
such
as a large capacity muffler, dual element air cleaner reduce noise
much easier in the design of power equipment.
is
offered in two stylish versions.
4-1.)
from
less fuel and prolonged engine life.
on
opposite sides, making the arrangements
OF
on
ENGINE COMPONENTS
the
shroud
with the
to
a minimum level.
for
cooling air
4-2
MAIN BEARING
The main bearing cover is an aluminum
diecasting, which is mounted
side of the crankcase. Remove the main bearing
cover
to
inspect inside
The main bearing cover also functions as an oil
pan, with,a trochoid
(See Fig.
4-2.)
COVER
of
the engine.
oil
pump and
..
on
the output shaft
oil
filler.
-3-
Fig.
Fig.
4-1
4-2
4-3
CRANKSHAFT
The crankshaft is a forged carbon steel, and the
crank pin
is
induction-hardened. The PTO end
the shaft has a crankshaft gear which is pressed
into position. (See
44
CONNECTING
Fig.
ROD
4-3.)
AND PISTON
of
Fig.
CRANKSHAFT
4-3
r,
GEAR
The connecting rod
is
a forged aluminum alloy,
and its large and small ends function as bearings.
The piston
4-5
CAMSHAFT
The camshaft is a hollow shaped
is
an aluminum alloy casting, and
and
made of
special cast iron with the camshaft gear casted
together.
A
centrifugal decompression lever is assembled
the camshaft. The lubrication oil
by the groove
(See Fig.
4-5.)
on
the end of the camshaft.
pump
is driven
on
Fig.
4-4
-4-
Fig.
4-5
4-6
VALVE ARRANGEMENT
The intake valve is located at flywheel side
'
cylinder head.
of
the
Hard alloy valve seats are molded in the cylinder
head and stellite is fused to the exhaust valve face.
The cylinder baffle leads cooling air to the exhaust
valve area for the optimum cooling.
(See
Fig.
4-6.)
4-7
CYLINDER HEAD
The cylinder head ,is an aluminum die casting,.
which utilizes wedge type combustion chamber for
the highest combustion efficiency.
(See Fig.
4-7.)
EXHAUST
Vi
Fig.
II
4-6
n
4-8
GOVERNOR SYSTEM
The governor is a centrifugal flyweight type which
ensures constant operation at the selected speed
against load variations.
The governor gear with governor weights is installed on the bearing cover and driven
camshaft gear. (See Fig.
4-8.)
by'
the
-5-
Fig.
Fig.
4-7
4-8
4-9
COOLING SYSTEM
The large fins
on
the flywheel provide sufficient cooling air capacity for the inlet and exhaust area and
cylinder.
The cylinder baffle helps the cooling air flow efficiently.
4-1
0
LUBRICATION
EH18V
EH18V
has a trochoid pump outside the main bearing cover that is driven by the camshaft.
uses
forced
splash
type lubrication.
(See
Fig.
4-9.)
/
M6
FLANGE BOLT
OIL
SHELTER
...
PLATE
1
pce.
CAMSHAFT
M,
AIN BEARING
COVER
OIL PUMP
COVER
Fig.
4-9
-6-
&-
M6
FLANGE
BOLT
...
4pcs.
4-1
1
IGNITION
The
ignition system
magneto ignition system which consists of a
SYSTEM
is
a transistor controlled
fly-
wheel and an ignition coil with a built in transistor
mounted on the crankcase.
This system has an automatic ignition timing
advancing for easier starting. (See Fig.
For details, refer to page
39,
section
4-10.)
6.
4-12
CARBURETOR
The engines are equipped with a horizontal draft
carburetor
that
has a float controlled
and a fixed main jet.
The carburetors are calibrated carefully for the
sure starting,
good
acceleration, low fuel consumption and sufficient output.
For the- datails, refer
CARBURETOR”.
4-13
AIR
The air-cleaner
.
element system. (See
(See
CLEANER
is
to
page 42, section
Fig.
4-11.)
a heavy-duty type with a dual
Fig.
4-12.)
fuel
system
“8
WING
BOLT
GROMMET
I;’
eo
.
Fig.
4-1
1
<
#(URETHANE FOAM)
:’
.
.’
J
CLEANER COVER
PRIMARY ELEMENT
-7-
Fig.
SECONDARY ELEMENT
SECONDARY ELEMENT
PAPER ELEMENT)
(PAPER ELEMENT)
4-12
4-14
DECOMPRESSION
An
automatic decompression mechanism which
opens exhaust valve
compression top is assembled
easy starting. (See
For details, refer
to
Fig.
page
SYSTEM
before
4-13)
41,
the piston reaches
on
section
the camshaft for
7.
[
AUTOMATIC DECOMPRESSION
RETURN SPRING
&$
SYSTEM
n
-a-
4-15
SECTIONAL
VIEW
OF
ENGINE
RECOIL
STARTER
\
BLOWER
I
HOUSING
MAIN
BEARING COVER
-9-
CRANKSHAFT
SPARK
PLUG
MUFFLER
CONNECTING
-
10
-
ROD
5.
DISASSEMBLY
5-1
PREPARATIONS AND SUGGESTIONS
AND
REASSEMBLY
When disassembling the engine, remember the locations
1)
reassembled correctly. If you are uncertain of identifying some parts,
attached to them.
Have boxes ready to keep disassembled parts
To
prevent missing and misplacing, temporarily assemble each group
Carefully handle disassembled parts, and clean them with