Yamaha EH63 User manual

SERVICE MANUAL
EH63
EH64
EH65
EH72
7D5-28197-E0
2019.03×1 !
7D5-28197-E0_cover.indd 1-2 2019/03/12 10:04:33

7D5-28197-E0_cover.indd 3-4 2019/03/12 10:04:33

EH63/EH64/EH65/EH72
SERVICE MANUAL
©2019 by Yamaha Motor Powered
Products Co., Ltd.
1st Edition, February 2019
All rights reserved.
Any reprinting or unauthorized use
without the written permission of
Yamaha Motor Powered
Products Co., Ltd.
is expressly prohibited.

IMPORTANT
This manual was produced by the Yamaha Motor Powered Products Co., Ltd. primarily for use by
Yamaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a
mechanic in one manual. Therefore, anyone who uses this book to perform maintenance and
repairs on Yamaha machines should have a basic understanding of mechanics and the techniques
to repair these types of machines. Repair and maintenance work attempted by anyone without this
knowledge is likely to render the machine unsafe and unfit for use.
Yamaha Motor Powered Products Co., Ltd. is continually striving to improve all of its models. Modifi-
cations and significant changes in specifications or procedures will be forwarded to all authorized
Yamaha dealers and will appear in future editions of this manual where applicable.
TIP
Designs and specifications are subject to change without notice.
IMPORTANT MANUAL INFORMATION
Particularly important information is distinguished in this manual by the following notations.
This is the safety alert symbol. It is used to alert you to potential personal injury hazards.
Obey all safety messages that follow this symbol to avoid possible injury or death.
A WARNING indicates a hazardous situation which, if not avoided, could result in death or
serious injury.
A NOTICE indicates special precautions that must be taken to avoid damage to the machine
or other property.
TIP
A TIP provides key information to make procedures easier or clearer.
WARNING
NOTICE

HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic.
Comprehensive explanations of all installation, removal, disassembly, assembly, repair and check
procedures are laid out with the individual steps in sequential order.
• The manual is divided into chapters and each chapter is divided into sections. The current section
title is shown at the top of each page “1”.
• Sub-section titles appear in smaller print than the section title “2”.
• To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section “3”.
• Numbers are given in the order of the jobs in the exploded diagram. A number indicates a disas-
sembly step “4”.
• Symbols indicate parts to be lubricated or replaced “5”. Refer to “SYMBOLS”.
• A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc. “6”. This step explains removal procedure only. For installation, reverse
the steps.
• Jobs requiring more information (such as special tools and technical data) are described sequen-
tially “7”.
PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
3-46
PISTONS AND CRANKSHAFT
Order Job/Parts to remove Q’ty Remarks
Removing the pistons and crankshaft Remove the parts in the order listed.
2pacdorgnitcennoC1
1tfahsknarC2
1mihstfahsknarC3
2dorgnitcennoC4
4pilcricnipnotsiP5
2nipnotsiP6
2
notsiP7
gnirpoT2gnirnotsiP8
gnirdn22gnirnotsiP9
gnirliO2gnirnotsiP01
1
2
3
4
5
6
7
8
9
10
5
5
7
10 98
5
6
1
25 N・m (2.5 kgf・m, 18 lb・ft)
25 N・m (2.5 kgf・m, 18 lb・ft)
4
PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT
3-54
INSTALLING THE CRANKCASE COVER
1. Install:
• Crankcase cover
• Crankcase cover bolts “1”–“10”
CHECKING THE CYLINDERS AND PISTONS
1. Check:
• Piston wall
• Cylinder wall
Vertical scratches →Replace the cylinder, and
replace the piston and piston rings as a set.
2. Measure:
• Cylinder warpage
TIP
Measure the warpage on the contact surface of the cylin-
der head at six points using a straight edge and thickness
gauge.
Out of specification →Replace the crankcase
assembly.
3. Measure:
• Piston-to-cylinder clearance
a. Measure the cylinder bore “C” with the cylinder
bore gauge.
10
1
2
3
45
6
7
8
9
10
Crankcase cover bolt:
25 N·m (2.5 kgf·m, 18 lb·ft)
T
R
.
.
Thickness gauge:
90890-03268
Feeler gauge set:
YU-26900-9
Warpage limit:
0.1 mm (0.0039 in)
1
7
2
6
3
4
5

SYMBOLS
The following symbols are used in this manual for easier understanding.
TIP
The following symbols are not relevant to every machine.
SYMBOL DEFINITION SYMBOL DEFINITION
Filling fluid Lubricant
Special tool Tightening torque
Wear limit, clearance Engine speed
Electrical data Replace the part with a new one.
Lithium-soap base grease Molybdenum disulfide grease
Engine oil Apply locking agent (LOCTITE®)
T
R
.
.
New
LS
M
E
LT

GENERAL INFORMATION
PERIODIC CHECKS AND
ADJUSTMENTS
ENGINE
FUEL
ELECTRICAL
TROUBLESHOOTING
SPECIFICATIONS
1
2
3
4
5
6
7
8
9
10
INDEX

TABLE OF CONTENTS
GENERAL INFORMATION
MACHINE IDENTIFICATION...................... 1-1
SERIAL NUMBER ................................. 1-1
DIMENSIONS ............................................. 1-2
DIMENSION CHART FOR P.T.O. .......... 1-2
TOP ....................................................... 1-4
MOUNTING BASE ................................ 1-4
LEFT SIDE ............................................ 1-5
FRONT .................................................. 1-5
REAR .................................................... 1-6
IMPORTANT INFORMATION..................... 1-7
PREPARATION FOR REMOVAL AND
DISASSEMBLY ..................................... 1-7
CAUTION ON SERVICE ....................... 1-7
NOTES ON SERVICE ........................... 1-7
ALL REPLACEMENT PARTS................ 1-8
GASKETS, OIL SEALS, AND
O-RINGS ............................................... 1-8
BEARINGS AND OIL SEALS................ 1-9
BASIC SERVICE INFORMATION .............. 1-9
ELECTRICAL SYSTEM ........................ 1-9
SPECIAL TOOLS AND TESTERS........... 1-13
PERIODIC CHECKS AND
ADJUSTMENTS
INTRODUCTION ........................................ 2-1
MAINTENANCE INTERVALS CHART ....... 2-1
PERIODIC MAINTENANCE/
LUBRICATION INTERVALS....................... 2-1
PERIODIC MAINTENANCE ....................... 2-3
SPARK PLUGS ..................................... 2-3
FUEL LEAKAGE ................................... 2-4
FUEL FILTER ........................................ 2-4
ENGINE OIL LEAKAGE ........................ 2-5
ENGINE OIL LEVEL.............................. 2-5
REPLACING THE ENGINE OIL ............ 2-6
OIL COOLER (EH72A/EH72B/
EH72K).................................................. 2-8
AIR FILTER ELEMENT ......................... 2-8
MUFFLER ........................................... 2-10
BREATHER HOSE .............................. 2-11
CYLINDER HEAD
DECARBONIZATION...........................2-11
ADJUSTING THE VALVE
CLEARANCE.......................................2-12
ENGINE SPEED (EH63K/EH64A/
EH64K/EH65A/EH65B) .......................2-14
ENGINE SPEED (EH72A/EH72B/
EH72K) ................................................2-16
FITTINGS AND FASTENERS..............2-18
ENGINE
ENGINE INSPECTION................................3-1
MEASURING THE COMPRESSION
PRESSURE ...........................................3-1
AIR FILTER .................................................3-3
EH63K/EH64A/EH64K/EH65A/
EH65B ...................................................3-3
EH72A/EH72B/EH72K...........................3-4
MUFFLER ...................................................3-5
EH63K/EH72B/EH72K...........................3-5
EH64K ...................................................3-6
EH65B ...................................................3-7
EH65A/EH72A .......................................3-8
INSTALLING THE MUFFLER ................3-9
OIL COOLER AND OIL FILTER ...............3-10
REMOVING THE OIL COOLER
(EH72A/EH72B/EH72K) ......................3-11
CHECKING THE OIL COOLER
(EH72A/EH72B/EH72K) ......................3-11
INSTALLING THE OIL COOLER
(EH72A/EH72B/EH72K) ......................3-11
RECTIFIER/REGULATOR ........................3-13
CASE AND FAN........................................3-14
REMOVING THE CASE AND FAN ......3-15
CHECKING THE CASE AND FAN ......3-15
INSTALLING THE CASE AND FAN.....3-16
CYLINDER COVERS ................................3-17
CYLINDER COVER 1 AND
CYLINDER COVER 2 ..........................3-17
CYLINDER COVER 3 ..........................3-18
TCI UNITS, FLYWHEEL AND STATOR
COIL ASSEMBLY .....................................3-19
TCI UNITS ...........................................3-19

FLYWHEEL AND STATOR COIL
ASSEMBLY ......................................... 3-20
REMOVING THE FLYWHEEL AND
STATOR COIL ASSEMBLY.................. 3-21
CHECKING THE FLYWHEEL AND
STATOR COIL ASSEMBLY.................. 3-22
INSTALLING THE FLYWHEEL AND
STATOR COIL ASSEMBLY.................. 3-22
INSTALLING THE TCI UNITS ............. 3-23
ENGINE SWITCH AND OIL WARNING
LIGHT (EQUIPPED MODELS ONLY) ...... 3-25
CYLINDER HEAD COVERS, CYLINDER
HEADS ..................................................... 3-26
CYLINDER HEAD #1 .......................... 3-26
CYLINDER HEAD #2 .......................... 3-29
CHECKING THE ROCKER ARMS ..... 3-32
REMOVING THE CYLINDER
HEADS ................................................ 3-32
CHECKING THE CYLINDER
HEADS ................................................ 3-32
INSTALLING THE CYLINDER HEAD
ASSEMBLIES...................................... 3-33
VALVES .................................................... 3-34
CYLINDER HEAD #1 .......................... 3-34
CYLINDER HEAD #2 .......................... 3-35
REMOVING THE VALVES AND
VALVE SPRINGS ................................ 3-36
CHECKING THE VALVES AND
VALVE SPRINGS ................................ 3-36
CHECKING THE VALVE SEATS ......... 3-38
VALVE LAPPING................................. 3-39
INSTALLING THE VALVES AND
VALVE SPRINGS ................................ 3-40
OIL PUMP................................................. 3-41
DISASSEMBLING THE OIL PUMP..... 3-42
CHECKING THE OIL PUMP ............... 3-42
ASSEMBLING THE OIL PUMP........... 3-42
PISTONS, CAMSHAFT, CRANKCASE,
AND CRANKSHAFT ................................ 3-44
CRANKCASE COVER ........................ 3-44
CAMSHAFT......................................... 3-45
PISTONS AND CRANKSHAFT........... 3-46
CRANKCASE ...................................... 3-47
CHECKING THE RELIEF VALVE........ 3-48
ASSEMBLING THE RELIEF VALVE ... 3-48
CHECKING THE OIL PUMP
STRAINER...........................................3-48
ASSEMBLING THE OIL PUMP
STRAINER...........................................3-48
REMOVING THE FLYWEIGHT
SHAFT ASSEMBLY AND
GOVERNOR FORK .............................3-48
DISASSEMBLING THE FLYWEIGHT
SHAFT ASSEMBLY .............................3-49
CHECKING THE FLYWEIGHT
SHAFT ASSEMBLY .............................3-49
ASSEMBLING THE FLYWEIGHT
SHAFT ASSEMBLY .............................3-50
INSTALLING THE FLYWEIGHT
SHAFT ASSEMBLY AND
GOVERNOR FORK .............................3-50
REMOVING THE CAMSHAFT AND
VALVE LIFTERS ..................................3-51
CHECKING THE CAMSHAFT.............3-51
CHECKING THE VALVE LIFTERS ......3-53
INSTALLING THE VALVE LIFTERS
AND CAMSHAFT ................................3-53
CHECKING THE CRANKCASE
COVER ................................................3-53
INSTALLING THE CRANKCASE
COVER ................................................3-54
CHECKING THE CYLINDERS AND
PISTONS .............................................3-54
CHECKING THE CRANKCASE ..........3-56
CHECKING THE PISTON PINS ..........3-56
CHECKING THE PISTON RINGS .......3-57
CHECKING THE CRANKSHAFT ........3-58
CHECKING THE CONNECTING
RODS OIL CLEARANCE.....................3-58
INSTALLING THE PISTONS AND
PISTON RINGS ...................................3-59
INSTALLING THE CRANKSHAFT.......3-60
SELECTING THE CRANKSHAFT
SHIM....................................................3-62
FUEL
FUEL PUMP................................................4-1
EH63K/EH64A/EH64K/EH65A/
EH65B ...................................................4-1
EH72A/EH72B/EH72K...........................4-2
CHECKING THE FUEL PUMP ..............4-3

CARBURETOR ASSEMBLY ...................... 4-4
REMOVING THE CARBURETOR
(EH63K/EH64A/EH64K/EH65A/
EH65B).................................................. 4-4
DISASSEMBLING THE
CARBURETOR (EH64A/EH65B) .......... 4-5
DISASSEMBLING THE
CARBURETOR (EH63K/EH64K/
EH65A).................................................. 4-7
REMOVING THE CARBURETOR
(EH72A/EH72B/EH72K)........................ 4-9
DISASSEMBLING THE
CARBURETOR (EH72A/EH72B/
EH72K)................................................ 4-10
REMOVING THE CARBURETOR
ASSEMBLY ......................................... 4-11
CHECKING THE CARBURETOR ....... 4-11
INSTALLING THE CARBURETOR
ASSEMBLY ......................................... 4-12
ADJUSTING THE GOVERNOR .......... 4-13
INTAKE MANIFOLD................................. 4-14
EH63K/EH64A/EH64K/EH65A/
EH65B ................................................. 4-14
EH72A/EH72B/EH72K ........................ 4-15
REMOVING THE INTAKE
MANIFOLD.......................................... 4-16
CHECKING THE INTAKE
MANIFOLD.......................................... 4-16
INSTALLING THE INTAKE
MANIFOLD.......................................... 4-16
ELECTRICAL
CIRCUIT DIAGRAM ................................... 5-1
ELECTRICAL COMPONENTS .................. 5-3
CHECKING THE SWITCH
CONTINUITY ........................................ 5-5
CHECKING THE OIL PRESSURE
SWITCH ................................................ 5-5
CHECKING THE IGNITION SPARK
GAP....................................................... 5-6
CHECKING THE AIR GAP.................... 5-7
CHECKING THE IGNITION COIL (TCI
UNIT, PRIMARY) RESISTANCE ........... 5-7
CHECKING THE IGNITION COIL (TCI
UNIT, SECONDARY) RESISTANCE ..... 5-7
CHECKING THE ENGINE SWITCH
(EQUIPPED MODELS ONLY) ...............5-8
CHECKING THE STARTER MOTOR
OPERATION ..........................................5-8
CHECKING THE WIRE HARNESS.......5-9
ELECTRIC STARTING SYSTEM..............5-10
REMOVING THE STARTER
MOTOR................................................5-10
CHARGING SYSTEM ...............................5-11
CHECKING THE STATOR COIL
ASSEMBLY ..........................................5-11
CHECKING THE RECTIFIER/
REGULATOR .......................................5-11
TROUBLESHOOTING
ENGINE DOES NOT START ......................6-1
ELECTRIC STARTING SYSTEM................6-2
ENGINE STARTS BUT STALLS.................6-2
ENGINE SPEED DOES NOT
INCREASE..................................................6-3
ENGINE SPEED IS UNEVEN .....................6-4
THE BATTERY (OPTION) IS NOT
CHARGED ..................................................6-4
GOVERNOR OPERATION..........................6-5
SPECIFICATIONS
GENERAL SPECIFICATIONS ....................7-1
MAINTENANCE SPECIFICATIONS ...........7-3
ENGINE .................................................7-3
ELECTRICAL.........................................7-7
TIGHTENING TORQUES............................7-8
GENERAL TORQUE
SPECIFICATIONS.....................................7-10
LUBRICATION POINTS AND TYPE OF
LUBRICANTS ...........................................7-11
WIRE ROUTING DIAGRAM .....................7-12
FUEL PUMP AND FUEL HOSE
(EH63K) ...............................................7-12

FUEL PUMP AND FUEL HOSE
(EH64A)............................................... 7-13
FUEL PUMP AND FUEL HOSE
(EH64K, EXCEPT FOR KOR) ............. 7-14
FUEL PUMP AND FUEL HOSE
(EH64K, FOR KOR) ............................ 7-15
FUEL PUMP AND FUEL HOSE
(EH65A)............................................... 7-16
FUEL PUMP AND FUEL HOSE
(EH65B)............................................... 7-17
FUEL PUMP AND FUEL HOSE
(EH72A)............................................... 7-18
FUEL PUMP AND FUEL HOSE
(EH72B, FOR SEA/EH72K, FOR
CHN) ................................................... 7-19
FUEL PUMP AND FUEL HOSE
(EH72K, EXCEPT FOR CHN)............. 7-20
AIR FILTER, CARBURETOR AND
FUEL HOSE (EH63K/EH64A/EH64K,
EXCEPT FOR KOR)............................ 7-21
AIR FILTER, CARBURETOR AND
FUEL HOSE (EH64K, FOR KOR/
EH65A/EH65B) ................................... 7-22
AIR FILTER, CARBURETOR AND
FUEL HOSE (EH72A/EH72B/
EH72K)................................................ 7-23
CARBURETOR AND INTAKE
MANIFOLD (EH64A/EH64K,
EXCEPT FOR KOR)............................ 7-24
CARBURETOR AND INTAKE
MANIFOLD (EH64K, FOR KOR/
EH65A/EH65B) ................................... 7-25
CARBURETOR AND INTAKE
MANIFOLD (EH72A/EH72B/
EH72K)................................................ 7-26
TCI UNIT (EH63K) .............................. 7-27
TCI UNIT (EH64A) .............................. 7-28
TCI UNIT (EH64K, EXCEPT FOR
KOR).................................................... 7-29
TCI UNIT (EH64K, FOR KOR) ............ 7-30
TCI UNIT (EH65A) .............................. 7-31
TCI UNIT (EH65B) .............................. 7-32
TCI UNIT (EH72A) .............................. 7-33
TCI UNIT (EH72B, FOR SEA/EH72K,
FOR CHN)........................................... 7-34
TCI UNIT (EH72K, EXCEPT FOR
CHN) ................................................... 7-35
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH63K)................7-36
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH64A)................7-37
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH64K, EXCEPT
FOR KOR) ...........................................7-38
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH64K, FOR
KOR) ....................................................7-39
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH65A)................7-40
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH65B)................7-41
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH72A)................7-42
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH72B,
FOR SEA/EH72K, FOR CHN) .............7-43
RECTIFIER/REGULATOR AND
STARTER MOTOR (EH72K, EXCEPT
FOR CHN) ...........................................7-44

MEMO

1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
1-1
GENERAL INFORMATION
MACHINE IDENTIFICATION
SERIAL NUMBER
The serial number is printed on the label affixed to the
position “1” of the multi-purpose engine as shown in the
illustration.
TIP
• The first four digits identify the model, and the remaining
digits indicate the production number.
• Designs and specifications are subject to change without
notice.
1

DIMENSIONS
1-2
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
DIMENSIONS
DIMENSION CHART FOR P.T.O.
mm (in)
35 (1.38)
19 (0.75)
28 (1.1)
63 (2.48)
80 (3.15)
M10 1.25
12 (0.47)
10.5 (0.41)
30 (1.18)
35 (1.38)
3 (0.12)
63 (2.48)
80 (3.15)
M10 1.25
21 (0.83)
28.58 (1.13)
7/16-20UNF-2B
99.3 (3.91)
38 (1.5)
47 (1.85)
85.5 (3.37)

DIMENSIONS
1-3
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
UNF: Unified fine thread (Unit: in)
A: EH65B, EH72B
B: EH65B, EH72B
C: EH64A, EH65A, EH72A
D: EH64A, EH65A, EH72A
E: EH63K, EH64K, EH72K
F: EH63K, EH64K, EH72K
28.58 (1.13)
13.5 (0.53)
12 (0.47)
3 (0.12)
7/16-20UNF-2B
99.3 (3.91)
40 (1.57)
49 (1.93)
85.5 (3.37)
35 (1.38)
22.1 (0.87)
19.2 (0.76)
16 (0.63)
24 (0.94)
5/16-24UNF-2B
35 (1.38)
5/16-24UNF-2B
10 (0.39)
8.5 (0.33)
18 (0.71)
3 (0.12)
26 (1.02)
19.2 (0.76)
22.1 (0.87)

DIMENSIONS
1-4
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
TOP
MOUNTING BASE
mm (in)
mm (in)
57.1 (2.25)
26 (1.02)
90.5 (3.56)
195 (7.68)
16 (0.63)
102
(4.02)
61.4
(2.42) 4.2 (0.17)
105.1 (4.14)
63.4 (2.5)
16 (0.63)
4 R5.3
4 10.6

DIMENSIONS
1-5
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
LEFT SIDE
FRONT
mm (in)
mm (in)
133.3 (5.25)
190.6 (7.5)
5 (0.2)
99.9 (39.3)
417.3 (16.43)
25 (0.98)
317.4 (12.5)
477 (18.78)
253.5 (9.98)
475 (18.7)

DIMENSIONS
1-6
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
REAR
*1: UNC: Unified coarse thread (Unit: in)
mm (in)
144 (5.67)
288.1 (11.34)
116 (4.57)
153.9 (6.06)
7/16-14 UNC
3/8-16 UNC
26 (1.02 )
26 (1.02 )
30°
30°
5°
45°
5°
45°
65 0.2 (2.56 0.01)
52 0.15 (2.05 0.01)
M8 1.25
M8 1.25
127 0.2
165.1 0.2
196.8 0.2
52 0.15 (2.05 0.01)

IMPORTANT INFORMATION
1-7
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL AND
DISASSEMBLY
CAUTION ON SERVICE
Fire prevention
When servicing the engine, always keep the engine and
yourself away from fire.
NOTES ON SERVICE
Correct tools
Be sure to use the correct special tool for the job to guard
against damage.
Oil, grease and seals
Be sure to use genuine Yamaha oils, grease and sealers,
or the equivalents.
Expendable parts
Always replace the gaskets, O-rings, cotter pins and cir-
clips with new parts when servicing engine.

IMPORTANT INFORMATION
1-8
1
2
3
4
5
6
7
8
9
10
GENERAL INFORMATION
Tightening torque
Be sure to follow torque specifications. When tightening
bolts, nuts or screws, start with the largest-diameter fas-
tener and work from an inner position to an outer position
in a crisscross pattern.
Notes on disassembly and assembly
• Parts should be cleaned in solvent and blown dry with
compressed air after disassembly.
• Contact surfaces of moving parts should be oiled when
reassembled.
• Make sure that the parts, move smoothly after each sec-
tion of the machine is assembled.
ALL REPLACEMENT PARTS
We recommend the use of genuine Yamaha parts for all
replacements. Use oil and/or grease, recommended by
Yamaha, for assembly and adjustment.
GASKETS, OIL SEALS, AND O-RINGS
1. All gaskets, seals, and O-rings should be replaced
when an engine is overhauled. All gaskets surfaces,
oil seal lips, and O-rings must be cleaned.
2. Properly oil all mating parts and bearings during reas-
sembly. Apply grease to the oil seal lips.