Kubota WG752 E3 Instructions for use

KUBOTA ENGINES
APPLICATION MANUAL
(WG752, WG972 E3 MODEL)
(DG972 E2 MODEL)
First Edition
January, 2011
KUBOTA

CONTENTS
1. PREFACE
2. GENERAL INFORMATION
0. GENERAL
1. EMISSION REGULATION
2. FUEL SYSTEM
3. EXHAUST SYSTEM
4. ELECTRICAL SYSTEM
3. TECHNICAL INFORMATION
4. APPLICATION CHECK SHEET
5. EXHAUST EMISSION CHECK SHEET
6. EMISSIONS-RELATED INSTALLATION
INSTRUCTION

1. PREFACE
1. This has been prepared so as to enable users to properly and efficiently utilize KUBOTA small SI
engines.
2. This manual describes the features of the engines, the cautions and the check items for mounting
the engines on various machines.
3. The contents of this manual are roughly divided into the following two items.
a) General information
b) Technical information
4. This manual describes only the content that should be mentioned specially for small SI engines.
Please also refer to the diesel engine application manual.
5. Phase3 emissions regulations require confirmation of “Emissions-Related Installation Instructions”,
“Contractual agreement” etc. between engine and equipment manufactures under 40CFR1068.
6. The specifications and features described in this manual are subject to change without advance
notice for technical improvement.
7. If you have any question about this manual, please contact with nearest KUBOTA sales
representatives or send e-mail to “[email protected]”.

2GENERAL INFORMATION

0. GENERAL
CONTENTS
1. SPECIFICATIONS......................................................................................................................... 0-1
2. PERFORMANCE CURVES........................................................................................................... 0-4
3. DIMENSIONS ................................................................................................................................ 0-6

0-1
1. SPECIFICATIONS
NOTE
• * LPG regulator with vaporizer operates on a liquid withdrawal type system.
Model
Item WG752-G-E3 WG752-GL-E3
Type Vertical, water cooled
4-cycle Gasoline engine
Vertical, water cooled 4-cycle Dual Fuel
(Gasoline/LPG)
Gasoline fuel LPG fuel
Number of cylinders 3
Cylinder bore x Stroke mm (in) 68.0 (2.68) x 68.0 (2.68)
Total displacement L (cu. in) 0.740 (45.2)
High idle min-1 (rpm) 3850
Low idle min-1 (rpm) 1500
Brake horse
power
SAE J1995 Gross
intermittent
kW (HP) /
min-1 (rpm)
18.5 (24.8) / 3600 17.7 (23.8) / 3600
SAE J1349 Net
intermittent 17.1 (23.0) / 3600 16.4 (22.0) / 3600
SAE J1349 Net
continuous 13.4 (18.0) / 3600 12.7 (17.0) / 3600
ISO Gross 18.5 (24.8) / 3600 17.7 (23.8) / 3600
ISO Continuous 13.4 (18.0) / 3600 12.7 (17.0) / 3600
JIS B8002 Net
Intermittent 17.1 (23.0) / 3600 16.4 (22.0) / 3600
JIS B8002 Continuous 13.4 (18.0) / 3600 12.7 (17.0) / 3600
Max. torque (SAE J1349) N·m (ft-lb)
min-1 (rpm) 54.9 (40.5) / 2400 52.0 (38.3) / 2400
Compression ratio 9.2
Firing order 1−2−3
Ignition timing B.T.D.C.18 °
Fuel Unleaded
gasoline
Commercial
LPG *
Direction of rotation Counter-clockwise from flywheel side
Starting system Electric starting with cell starter
Starter output V-kW 12−0.7
Alternator output V-W 12−150 (Standard)
Lubricating system Forced lubricating by trochoid pump
Lubricating oil Quality better than SH class
Lubricating oil capacity L (U.S. gal) 3.25 (0.86)
Catalytic Muffler / Converter Three Way Catalyst
Coolant capacity (with radiator) L (U.S. gal) 2.8 (0.74)
Governor type Centrifugal ball mechanical type governor
Dimensions (L x B x H) mm (in) 428.5 x 396.9 x 539.8 (16.87 x 15.63 x 21.25)
Dry weight kg (lb) Approx. 61.7 (136.0)

0-2
NOTE
• *1 Consult Kubota for further information.
• *2 LPG regulator with vaporizer operates on a liquid withdrawal type system.
Model
Item WG972-G-E3 WG972-GL-E3
Type Vertical, water cooled
4-cycle Gasoline engine
Vertical, water cooled 4-cycle Dual Fuel
(Gasoline/LPG)
Gasoline fuel LPG fuel
Number of cylinders 3
Cylinder bore x Stroke mm (in) 74.5 (2.93) x 73.6 (2.90)
Total displacement L (cu. in) 0.962 (58.7)
High idle min-1 (rpm) 3850
Low idle min-1 (rpm) 1500
Brake horse
power
SAE J1995 Gross
intermittent
kW (HP) /
min-1 (rpm)
24.2 (32.5) / 3600 23.1 (31.0) / 3600
SAE J1349 Net
intermittent 23.1 (31.0) / 3600 22.0 (29.5) / 3600
SAE J1349 Net
continuous 18.7 (25.0) / 3600 17.5 (23.5) / 3600
ISO Gross 24.2 (32.5) / 3600 23.1 (31.0) / 3600
ISO Continuous 18.7 (25.0) / 3600 17.5 (23.5) / 3600
JIS B8002 Net
Intermittent 23.1 (31.0) / 3600 22.0 (29.5) / 3600
JIS B8002 Continuous 18.7 (25.0) / 3600 17.5 (23.5) / 3600
Max. torque (SAE J1349) N·m (ft-lb)
min-1 (rpm) 68.6 (50.6) / 2400 64.6 (47.6) / 2400
Compression ratio 9.2
Firing order 1−2−3
Ignition timing B.T.D.C. 8 ° / 1000 min-1 (rpm) B.T.D.C. 21 ° / 3600 min-1 (rpm) *1
Ignition system Distributor-less Solid State type
Fuel Unleaded
gasoline
Commercial
LPG *2
Direction of rotation Counter-clockwise from flywheel side
Starting system Electric starting with cell starter
Starter output V-kW 12−1.0
Alternator output V-W 12-480 (Standard)
Lubricating system Forced lubricating by trochoid pump
Lubricating oil Quality better than SH class
Lubricating oil capacity L (U.S. gal) 3.4 (0.90)
Catalytic Muffler / Converter Three Way Catalyst
Coolant capacity (with radiator) L (U.S. gal) 3.5 (0.92)
Governor type Centrifugal ball mechanical type governor
Dimensions (L x B x H) mm (in) BBH : 452.6 x 416.4 x 502.5 (17.82 x 16.39 x 19.78)
SAEH : 525.5 x 416.4 x 502.5 (20.69 x 16.39 x 19.78)
Dry weight kg (lb) Approx. 72.0 (159)

0-3
NOTE
• *1 Consult Kubota for further information.
• *2 With Japanese standard natural gas.
The lower heating value : 9699kcal/m3 (1090BTU/ft3).
CAUTION
• This engine is only for stationary use. e.g. oil field and emergency generator.
• The brake horse power is limited under 19kW for emission regulations.
Model
Item DG972
Type Vertical, water cooled 4-cycle Natural Gas engine
Number of cylinders 3
Cylinder bore x Stroke mm (in) 74.5 (2.93) x 73.6 (2.90)
Total displacement L (cu. in) 0.962 (58.7)
High idle min-1 (rpm) 3850
Low idle min-1 (rpm) 1500
Brake horse
power
SAE J1995 Gross
intermittent
kW (HP) /
min-1 (rpm)
18.7 (25.1) / 3600 *2
SAE J1349 Net
intermittent 17.6 (23.6) / 3600 *2
SAE J1349 Net
continuous 14.5 (19.4) / 3600 *2
ISO Gross 18.7 (25.1) / 3600 *2
ISO Continuous 14.5 (19.4) / 3600 *2
JIS B8002 Net
Intermittent 17.6 (23.6) / 3600 *2
JIS B8002 Continuous 14.5 (19.4) / 3600 *2
Max. torque (SAE J1349) N·m (ft-lb)
min-1 (rpm) 55.0 (40.5) / 2400 *2
Compression ratio 9.2
Firing order 1−2−3
Ignition timing B.T.D.C. 15 ° / 1000 min-1 (rpm) B.T.D.C. 28 ° / 3600 min-1 (rpm) *1
Ignition system Distributor-less Solid State type
Fuel Natural Gas only *2
Direction of rotation Counter-clockwise from flywheel side
Starting system Electric starting with cell starter
Starter output V-kW 12−1.0
Alternator output V-W 12-480 (Standard)
Lubricating system Forced lubricating by trochoid pump
Lubricating oil Quality better than SH class
Lubricating oil capacity L (U.S. gal) 3.4 (0.90)
Coolant capacity (with radiator) L (U.S. gal) 3.5 (0.92)
Governor type Centrifugal ball mechanical type governor
Dimensions (L x B x H) mm (in) BBH : 452.5 x 415.4 x 502.53 (17.81 x 16.35 x 19.78)
SAEH : 525.5 x 415.4 x 502.53 (20.69 x 16.35 x 19.78)
Dry weight kg (lb) BBH : Approx. 72.0 (159)
SAEH : Approx. 95.4 (210)

0-4
2. PERFORMANCE CURVES

0-5

0-6
3. DIMENSIONS
WG752-G-E3BBH-1 (EG641-00000)

0-7
WG752-GL-E3BBH-1 (EG645-00000)

0-8
WG972-G-E3BBH-1 (EG801-00000)

0-9
WG972-GL-E3BBH-1(EG805-00000)

0-10
WG972-GL-E3SAEH-1 (EG802-00000)

0-11
DG972-E2-BBH-1 (EG581-00000)

0-12
DG972-E2-SAEH-1 (EG582-00000)

0-13
WG752, WG972, DG972
Flywheel : Normal SAE for Clutch No.6-1/2
Flywheel Housing : Normal SAE No.5

1. EMISSION REGULATION
CONTENTS
1. GENERAL...................................................................................................................................... 1-1
2. IMPORTANT ITEMS...................................................................................................................... 1-2
[1] Important Notice ...................................................................................................................... 1-2
[2] Emission-Related Installation Instructions ............................................................................... 1-3
(1) Air Intake System .............................................................................................................. 1-3
(2) Exhaust System (See EXHAUST SYSTEM section) : (WG752, WG972)......................... 1-5
(3) High Altitude Operation (See FUEL SYSTEM section) : (WG752, WG972) ..................... 1-5
(4) Evaporative Emission Controls.......................................................................................... 1-5
(5) Engine Set Speed.............................................................................................................. 1-5
(6) Engine Labels.................................................................................................................... 1-6
(7) Vaporizer (WG752−GL, WG972−GL), Gas Regulator (DG972) Connections................... 1-6
(8) Tamper Resistance ........................................................................................................... 1-6

1-1
1. GENERAL
Along with E3 models, E2 models are yet available to be used in the following countries per output category.
NOTE
• * DG972 is only for stationary use.
e.g.oil field and emergency generator.
Current and future emission regulations.
HC+NOX/CO (g/kWh)
NOTE
• * with evaporative emission regulation
kW, disp. Model Type North America Europe Japan
P ≤19
0.225 ≤L
WG752-G/GL-E3 E3 Available Non-available Available
WG/DF752-E2 E2 Non-available Available Available
DG972 * E2 Available Available Available
19 < P ≤30
0.825 < L ≤1.0
WG972-G/GL-E3 E3 Available Available Non-available
WG/DF972-E2 E2 Non-available Available Non-available
Countries kW, disp. 2009 2010 2011 2012 2013 2014 2015 2016
USA
CARB
P ≤19
0.225 ≤L 8.0/549 *
19 < P
L ≤0.825 12.0/549 8.0/549 *
19 < P
0.825 < L ≤1.0 12.0/549 6.5/375 * 0.8/20.6 *
EPA
P ≤19
0.225 ≤L 12.1/610 8.0/610 *
19 < P ≤30
L ≤1.0 12.1/610 8.0/610 *
Canada P ≤19
0.225 ≤L 12.1/610 8.0/610
Japan
P < 19
0.225 ≤L 12.1/610
19 ≤P < 560 HC/0.6 g/kWh, NOX/0.6 g/kWh, CO/20 g/kWh
EU
P ≤19
0.225 ≤L 12.1/610
19 < P None