Robin America EH12-2, EH17-2, EH25-2 User manual

CONTENTS
Section Title
1 .
2 .
3 .
4 .
5 .
6 .
7 .
8 .
Page
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-1
0
4-1 1
4-1 2
4-13
4-1 4
4-1
5
4-1 6
4-1 7

I. SPECIFICATIONS
~~ ~ ~~~ ~ ~ ~~ ~~ ~~~ ~~~~ ~~ ~~~ ~ ~
EH 12-2
EH12-2B EH12-2DS EHl2-2D EH12-2BS
Model
TY Pe
Air-Cooled, 4-Cycle, Single-Cylinder, Horizontal P.T.O. Shaft, Gasoline Engine
Bore
X Stroke
Piston Displacement
60
x 43 rnm (2.36 x 1.57 in.)
121
cm3 (7.38 cu.in.)
I
Max. Torque
Nem (kaf*m)/rDm 15 (1
52) /1300 7.5 (0.76)/2600
Direction
of Rotation
Cooling system
Counterclockwise
As Viewd From P.T.O. Shaft Side
Forced Air Cooling
Valve Arrangement
Lubrication
Overhead Valve
Splash Type
~~ ~ ~~~~~ ~~ ~
Lubricant
Capacityof Lubricant
0.6 L (0.16 U.S. gal.)
~~ ~
Automobile Oil SAE #20, #30or 1OW-30 ; Class SE,SF or higher
I Carburetor I HorizontalDraft,FloatType
I Fuel I AutomobileGasoline
~~~~~~~ ~~
310 g/KW*h (230gr/HP*h) At Continuous Rated Output
~ ~~~
I FuelFeedSystem I GravityType
FuelTank Capacity
Flywheel Magneto (Solid State) Ignition System
3.6 L (0.95
U.S. gal.)
I SparkPlug NGK BGES
Charging Capacity
Starter
Recoil Starter Starting System
12V - 1.3A
-
12V - 1.3A
-
Recoiland Electric
Starter Recoil and Electric
Recoil Starter
I SpeedReduction 2:l Cam Shaft Drive
Governor System Centrifugal Flyweight System
Dry Weight
Length
15.5 kg(34.2Ib.)
I 18.0 kg (39.7Ib.) I 15.0kg(33.1Ib.) I 17.5kg (38.6Ib.)
299mm (11.77 in.)
I 299mm (11.77 in.) I 297mm (11.69 in.) I 297mm(ll.69in.)
330mrn (12.99in.)
366mm (14.41 in.) 341mm (13.43in.) 366mm (14.41 in.)
-1-

EH17-2
EH17-2B EH17-2DS
EH17-2D
EH17-2BS
Model
TY Pe
Air-Cooled, 4-Cycle, Single-Cylinder, Horizontal P.T.O. Shaft, Gasoline Engine
Bore
X Stroke
~~ ~~ ~~ ~~~~ ~ ~
67 x 49 mrn (2.64 X 1.93 in.)
172cm3(10.50cu.in.)
.
Compression Ratio 8.5
Output 2.6
(3.5) /3000 2.9 (4.0) /3600
2.6
(3.5) / 1500 2.9 (4.0) / 1800
Continuous
Kw (HP)/rpm 4.4 (6.0)/4000
4.4 (6.0) /2000
Max.
Max. Torque
Nom (kgf*m)/rpm 21.4 (2.1 8)
/ 1300
1 0.7 (1 -09) / 2600
I I
Directionof Rotation Counterclockwise
As Viewd From P.T.O.Shaft Side
I Coolingsystem I Forced Air Cooling
I ValveArrangement I
~~
Overhead Valve
I Lubrication I SplashType
~ ~~ ~~ ~
Lubricant
Capacityof Lubricant
Horizontal Draft, Float Type Carburetor
0.65
L (0.17 U.S. gal.)
~~~~~~~ ~ ~_____ _____ ~ ~
Automobile Oil SAE #20,#30 or 1OW-30 ; Class SE, SF or higher
Fuel
310g/KW-h (230gr/HP*h) At Continuous Rated Output
Fuel Consumption Rate
Automobile Gasoline
Fuel Feed System
3.6 L (0.95 US. gal.)
Fuel Tank Capacity
Gravity Type
Flywheel Magneto (Solid State)
Spark Plug
12V
- 1.3A
-
12V - 1.3A
-
Charging Capacity
NGK B6HS
I StartingSystem
Speed Reduction
Centrifugal Flyweight System Governor System
-
2:l Cam Shaft Drive
Dry Weight
Dimensions
16.5 kg (36.4 Ib.)
341
rnm (13.43in.:
330
rnm (12.99in.)
341
rnrn (13.43in.) 330 mm (12.99in.)
Width
299mm(ll.77in.)
299
mm (11.77 in.) 301 mrn (1 1.85 in.)
301
mm (11.85 in.)
Length
18.5 kg
(40.8 Ib.)
16.0 kg (35.3 Ib.)
19.0 kg (41.9 Ib.)
Height 380mm (14.96in.) 380rnm (14.96in.) 380mm (14.96in.) 380rnm (14.96in.:
-2-

~~~~~~ ~~ ~
EH25-2
EH25-2 6
EH25-2DS
EH25-2D
EH25-26s
Model
TY Pe
Air-Cooled, 4-Cycle, Single-Cylinder, HorizontalP.T.O. Shaft, Gasoline Engine
Bore
x Stroke
Piston Displacement
75 X 57 mm (2.95 X 2.24 in.)
251 cm3(15.31cu.in;)
Compression Ratio
8.5
output 4.0
(5.5) /3000 4.7 (6.4) /3600
4.0
(5.5) I1 500 4.7 (6.4) / 1800
Continuous
Kw (HP)hm 6.3
(8.5) /4000
6.3
(8.5) /2000
Max.
Max. Torque
Nom (kgf*m)/rpm 33.1 (3.38)
/ 1300 16.6 (1.69)
/ 2600
Direction
of Rotation I CounterclockwiseAsViewdFrom P.T.O.ShaftSide
Cooling system
Valve Arrangement
Forced Air Cooling
Overhead Valve
Lubrication
Automobile Oil SAE#20,#30or
1 OW-30 ; Class SE, SF or higher Lubricant
Splash Type
Capacityof Lubricant
1 .O L (0.26 U.S. gal.)
Carburetor
Fuel
Horizontal Draft, Float Type
Automobile Gasoline
~ ~~~ ~ ~ ~ ~~~~~
Fuel Consumption Rate
Fuel Feed System
31
0 g/KW*h (230 gr / HP-h) At Continuous Rated Output
GravityType
Fuel Tank Capacity
Flywheel Magneto (Solid State)
Ignition System
6.0
L (1 59 U.S. gal.)
Spark Plug
12V
- 1.3A
-
12V - 1.3A
-
Charging Capacity
NGK B6HS
Starting System Recoil Starter
Starter
Recoil and Electric
Recoil Starter 1 Starter Recoiland Electric
SpeedReduction
I 2:l CamShaftDrive I -
GovernorSystem I CentrifugalFlyweightSystem
Dry Weight
332mm(l3.07in.)332mm (13.07in.)
333mm (13.11in.)
333mm (13.11 in.)
I Length
27.0kg (59.5
Ib.) 23.0 kg (50.7 Ib.) 28.0 kg (61.7 Ib.)
24.0 kg (52.9
Ib.)
~~~ ~~
Dimensions
440mm (17.32in.)440mm (17.32in.)
440mm (17.32in.)
440mm (17.32in.)
Height
380mrn (14.96in.)380mm (14.96in.)
380mm (14.96in.)
380mm (14.96in.)
Width
-3-

2-1 MAXIMUMOUTPUT
The maximum output is the output of an engine with its throttle valve fully opened under the condition
that all the moving parts are properly
worn in after the initial break-in period.
A new engine may not produce full maximum output while its moving parts are still not broken-in.
2-2 CONTINUOUS RATED OUTPUT
Thecontinuousratedoutputistheoutput of anengineatoptimumgovernedspeedwhichismost
favorable from the view point
of engine’s life and fuel consumption.
Whentheengine
is installed on a certainequipment, it is recommendedthatthecontinuousoutput
required from the enginebe 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
certainrevolution.
-4-

2-4 PERFORMANCECURVES
8 0 EHlPD, B
HP kW
4
3
+ 3 l2
n
+
0
3
1
0
2
1
for B type
2000 3000
(1 000) (1 500)
REVOLUTION - r.p.m.
4000
(2000)
-5-

0 EH17D, 6
for B tvDe
(1 000)
REVOLUTION - r.p.m.
N.m kgfam
3000 4000
(1 500) (2000)
-6-

EH25D, B
HP
8
7
t:
$4
&
I-
2
1
0
r I I I I I I I I I
I
"
"-
I I
1
"
MAXIMUM TORQUE AL\
I I I I I
kW I I MAXIMUM HORSEPOWER '(NET) I
-6
5
4
I
RECOMMENDED
I
i
N.m kgf-m
16.5 (33)
15.5 (31)
14.5
(29)
1.7 (3.4)
1.6 (3.2)
1.5 (3.0)
1.4 (2.8)
c
2000 3000 ' 4000
(1 000) (1 500) (2000)
REVOLUTION - r.p.m.
-7-

3. FEATURES , ,
1. Theoverheadvalvedesignoffers a compactness,lightweightandidealcombustioncharacteristics
2. An optimum lubrication and better tilted operation thanks to upright cylinder design.
3. A crossflow arrangement of intake and exhaust ports ensures stable performance under high ambient
temperature.
4. Theautomaticdecompressiomsystemlightens the recoilpull force by 40% comparingtothe
conventional
SV engines.
5. An easy operation thanks to integrated engine control system.
Improved throttle mechanism
is adopted foreasy starting.
6. Combustionandmechanicalnoiseshavebeenanalyzedacousticallyandimprovedforbettertonal
quality and lower engine noise.
7. Optimallydesignedreciprocatingpartsreducethevibrationlevel of theengine. EH25-2 engine
equips single through-balancer shaft as an option.
resulting in more power from Iess fuel and prolonged engine life.
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS
4-1 CYLINDER AND CRANKCASE
The cylinder and crankcase is single piece aluminum
diecasting.Thecylinderliner,made of specialcast
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.
4-2 MAIN BEARING COVER
Themainbearingcover is analuminumdiecasting,
which
is mounted on theoutputshaftside of the
crankcase.
Remove the main bearing cover to inspect the inside
of the engine.
The pilots and bosses are machined on the cover for
direct mounting of the engine onto such machines
as
generators and pumps.
Oil gauge (fillers) are on both sides of the cover for
easy maintenance.
Fig. 4-1
OILGAUGE OIL GAUGE
/"-
\
/"
Fig. 4-2
-8-

4-3 CRANKSHAFT
The crankshaft is forged carbon steel, and the crank
The output endof the shaft has a crankshaft gear, and
balancergearfor
EH25-2 whicharepressedinto
position.
W pinisinduction-hardened.
44 CONNECTING ROD AND PISTON
The connecting rod is an aluminum alloy diecasting,
and
its largeandsmalIendsfunctionasbearings.
Thepiston
is an aluminumalloycasting,andcarries
two compression rings and one
oil ring.
4-5 PISTONRINGS
The piston rings are made of special cast iron.
Theprofile of thetopring
is barrelfaceandthe
second ring has a tapered
face.
The oil ringconsists of acutterring anda coil
expander for better sealing and less oil consumption.
B TYPE
D TYPE
Fig. 4-3
I
fig. 4-4
TOP RING
SECOND RING
OIL RING
fig. 4-5
-9-

4-6 CAMSHAFT
Thecamshaft for theD-typeengine ismade of
specialcastiron and camshaftgearsarecastedto-
gether
in one piece.
Both sides of the shaft fit into the plane bearings on
the crankcaseand main bearing cover.
ThecamshaftfortheB-typeengineismade of
forged carbon steel and also functions as PTO shaft.
The cam gear
is press fitted on the shaft and the ball
bearingsareemployed
on both sidesforsupporting
the shaft.
4-7 VALVEARRANGEMENT
Theintakevalveislocated on flywheelside of the
cylinder head.
The hard alloy valve seatsaxe molded in the cylinder
head and stellite is fused to the exhaust valve face.
Thecylinderbaffleleadscoolingair to the exhaust
valve area for the optimum cooling.
4-8 CYLINDER HEAD
The cylinder head is an aluminum die casting which
utilizeswedge
type combustionchamber for the
highest combustion efficiency.
B TYPE
D lYPE
Fig. 4-6
n
/
INTAKE
Fig. 4-7
Fig. 4-8
- 10 -

4-9 GOVERNORSYSTEM
Thegovernor is acentrifugalflyweighttypewhich
ensuresconstantoperationattheselectedspeed
against load variations.
The governor gear with governor weights is installed
on the main bearing cover.
4-10 COOLINGSYSTEM
Thelargefinsontheflywheelprovidesufficient
coolingaircapacity
for theinletandexhaustarea
and cylinder.
Thecylinderbafflehelpsthecoolingairfloweffi-
ciently.
GOVERNOR GEAR
/
Fig. 4-9
4-1 1 LUBRICATION
Alltherotatingandslidingpartsaresplash-
lubricated by the oil scraper on the connectingrod.
I
OIL SCRAPER
Fig. 4-10
4-1 2 -IGNITION SYSTEM
Theignitionsystemis atransistorcontrolledmag-
neto ignition system which cosists of a flywheel and
an ignition coil witha built in transistor.
This system has an ignition timing advance for easy
starting.
Fig. 4-1 7
- 11 -

4-13 CARBURETOR
Theenginesareequippedwithahorizontaldraft
carburetor that has a float controlled fuel system and
a
fixed main jet.
Thecarburetors are calibratedcarefullyforeasy
starting,goodacceleration,lowfuelconsumption
and sufficient output.
4-14 AIR CLEANER
The air cleaner is a single urethane foam element system. As anoption,heavydutytypewith a double
element type is available.
CLEANER
CASE
Single elementtype
Fig. 4- 1 3- I
4-15 BALANCER (Option for EH25-2)
Unbalanced inertia force is balanced by the balancer
whichrotates at thesamespeedwiththe crankshaft
to effectively reduce vibration.
CLEANER COVER
Doubleelement type
Fig. 4- 13-2
BALANCER
I
- Fig. 4-14
- 12-

4-16 DECOMPRESSION SYSTEM
An automaticdecompressionmechanismwhich
opensexhaustvalvebeforethepistonreachescom-
pressiontop
is assembledonthecamshaftforeasy
starting.
AUTOMATIC DECOMPRESSOR SYSTEM
Fig. 4-14
- 13-

4-1 7 SECTIONAL VIEW OF ENGINE
FUEL TANK
FLYWHEEL MAIN BEARING COVER
- 14-

a
ROCKER ARM PUSH ROD
- 15 -

5. DISASSEMBLY AND REASSEMBLY
5-1 PREPARATIONSANDSUGGESTIONS
1) Whendisassemblingtheengine,memorizethelocations of individualparts so thatthey canbe
reassembedcorrectly. If yor areuncertain
of identifyingsomeparts,it is suggestedthattagsbe
attached to them.
2) Have boxes readyto keep disassembed partsby group.
3) To prevent losing and misplacing, temporarily assemble each group of disassembed parts.
4) Carefully handle disassembed parts, and cleanthem with washing oil if necessary.
5) Use the correct tools in the correct way.
5-2 SPECIAL TOOLS
Tool No. Use
Tool
209 - 95004- 07 For pulling off theflywheel EH25-2
Flywheel puller with bolt
Market parts
For pulling off theflywheel EH12-2, EH17-2
Flywheel puller
/"-
FLYWHEELPULLER FLYWHEEL
PULLER
Fig. 5-1
- 16 -

5-3 DISASSEMBLYPROCEDURES
Step
Tool
RemarksProcedures Part to remove
I
1
14mm box wrench
Be careful
not to lose the
(1) Remove oil drain plug and drain oil.Oil drain
(2) To discharge oil quickly, remove oil gasket.
gauge.
GASKET
I
Fig. 5-2
DRAIN PLUG
- 17 -