This product is subject to change for the purpose of improvement.
THE WG752-E2/DF752-E2 ENGINE CONFORMS TO 2008 AND LATER
U.S. EPA PHASE 2 AND EU EMISSION REGULATIONS FOR SI
SOREs.
2EPA USEFUL LIFE CATEGORY: A
READ AND SAVE THIS BOOK
PRINTED IN JAPAN AM . J . 7 - 19 . 20 . AK Code No. EG601-8916-5
INTRODUCTION
Thank you very much for purchasing a KUBOTA engine.
This operator’s manual is intended to acquaint you with the right way of using/ operating this engine with hints on routine checking and care.
Please read this manual carefully and observe the hints given etc. so that your engine can fully exhibit its true performance for a long time.
SPECIFICATIONS
Item
Type
No. of cyl. – bore 쎹 stroke
Total displacement
Brake horse power
SAE Gross int.
SAE net int.
Max. torque
Governor type
Ignition system
Fuel used
SAE net cont.
SAE net int.
Lubricating oil capacity
Starter
Total dimensions (L 쎹 W 쎹 H)
Weight (Dry)
Common tune up specification
Adjustment of idle speed
High idle setting
Ignition timing
Spark plug type / Spark plug gap
Intake / Exhaust valve clearance
Check when engine is cold.
Unit mm (in.)
L (cu-in.) kW(HP)/rpm
N·m(ft·lbs)/rpm
L (US gal.) mm (in.) kg (lbs)
WG752-E2
Gasoline
DF752-E2
Gasoline LPG
Vertical, Water-cooled 4 cycle
3-C68 쎹 L68 (3-C2.68 쎹 L2.68)
0.740 (45.21)
18.5 (24.8) / 3600
17.1 (23.0) / 3600
13.4 (18.0) / 3600
54.9 (40.5) / 2400
17.7 (23.8) / 3600
16.4 (22.0) / 3600
12.7 (17.0) / 3600
52.0 (38.3) / 2400
Centrifugal ball mechanical type
Full transistor (no points)
Unleaded gasoline Commercial LPG*
3.25 (0.859)
12 V 쎹 0.7 kW
421 (16.57) 쎹 392 (15.43) 쎹 540 (21.26)
61.7 (136.0) r/s (rpm) r/s (rpm) deg. BTDC mm (in.)
1500 앧100
3850 ~ 3950
18 앧1
NGK BKR4E-11/1.0~1.1 (0.039~0.043) mm (in.) 0.165
앧0.02 (0.0065앧0.00079)
Specifications subject to change without notice.
* NOTE : LPG regulator with vaporizer operates on a liquid withdrawal type system.
3
SAFE OPERATION
1. Before operation, wear a proper cap and work clothes to prevent clothing, hair, towels and such from getting caught in the engine.
2. Before operation, check all set bolts and nuts for looseness and tighten them if necessary.
3. Avoid placing inflammable materials close to the engine during operation.
4. As exhaust gases are harmful :
(1) Avoid operating the engine in an ill-ventilated place or where exhaust gases accumulate easily.
(2) Take special care during operation to prevent exhaust gases from affecting yourself, or people or animals around you.
5. Be sure to keep the flywheel safety covered during operation.
6. When using a fan belt, install a cover, fence or similar device to prevent the risk of injury.
7. Keep children and pets away from the engine during operation.
8. Do not touch the muffler, exhaust pipe or other hot parts, during or immediately after operation.
9. Always stop the engine in the following cases :
(1) When checking, adjusting or cleaning each part
(2) When discharging, pouring or injecting oil from or into each part
(3) When cleaning off dust or other foreign matter accumlated on the muffler
(4) When checking radiator coolant level
10. If the engine is to be lent to someone, explain the handling procedures and point out that the Operator’s Manual must be read carefully before use.
11. Use the standard LPG fuel recommended by KUBOTA. The use of other fuel may cause a hazardous or dangerous condition.
12. LPG fuel in the gaseous state is heavier than air and will settle in low areas, this may be hazardous.
Please follow all operator’s manual instructions when changing the fuel tank and servicing the fuel system.
LONG-TERM STORAGE
In order to keep the engine in good working condition, be sure to observe the following.
(1) Close the liquid withdrawal valve of the LPG fuel tank and start the engine to empty the fuels in fuel pipings. (DF752-E2)
(2) Empty the gasoline fuel tank.
(3) Loosen the drain screw of the carburetor float chamber using a screw driver to let gasoline out of the carburetor.
(4) Store the engine or its equipment in a wellventilated and shady place.
(5) Remove the battery, recharge it, adjust the electrolyte to the proper level, and store it in a dry and shady place.
IMPORTANT INFORMATIONS OF EXHAUST EMISSION REGULATION
쏋 To conform to U.S. EPA and EU SOREs (Small Off-Road Engines) emission regulations, the following standards must be followed before using the WG752-E2/DF752-E2 engine.
1. INLET AND EXHAUST SYSTEM (COMMON)
THE WG752-E2/DF752-E2 ENGINE MUST USE THE BELOW AIR CLEANER AND INLET
PIPE, AND EXHAUST BACK PRESSURE OF THE MUFFLER MUST BE WITHIN THE
BELOW VALUES;
PART
GENUINE AIR CLEANER
GENUINE INLET PIPE
PART NO.
15372-11010
12581-11620
BRAKE HORSE POWER SAE net int.
17.1 kW (23 HP)/ 3600 rpm
ALLOWABLE MAXIMUM
EXHAUST BACK PRESSURE
19.6 kPa (147.1 mmHg)/ 3600rpm
Any modifications to the fuel system or any adjustments made on this engine will cause this engine to be in non-compliance with emission regulations.
See “LPG FUEL SYSTEM AND DIAGRAMS” and “TAMPER RESISTANCE” section.
2. KUBOTA RECOMMENDED LPG FUEL SPECIFICATIONS (DF752-E2)
¡ Commercial Propane gas only.
¡ Equivalent to Propanes H-D-5 of GPA* standards.
C
3
H
8
C
3
H
6
C
4
H
10
Others
X90% Z5% Z2.5% –
(vol %)
* GPA means Gas Processors Association (U.S.A)
3. LENGTH OF THE LPG VAPOR HOSE (DF752-E2)
The length of the LPG vapor hose between the LPG carburetor and its regulator must be within 300 앧 20mm (11.8 앧 0.8 in.)
The incorrect use of the hose may not conform to EPA EMISSION REGULATIONS.
4. LPG REGULATOR WITH VAPORIZER (DF752-E2)
When operating DF752-E2 on LPG, only a KUBOTA GENUINE LPG REGULATOR KIT can be used.
Only this regulator can be installed by an authorized KUBOTA DISTRIBUTOR or the manufacturer of the equipment in which this engine is used.
5. HIGH ALTITUDE OPERATION
쏋 IMPORTANT
Altitude compensation kit is applied for EPA certified engines only.
EPA emission regulations require the ultimate users of non-road SI engine under 19 kW, as their obligation, to adjust the emissions by installing the appropriate genuine altitude compensation kit. And the engine manufacturer must provide such kit when the engine is operated at an altitude that exceeds the standard level, as guarantied by the engine manufacturer. For this purpose, KUBOTA prepared genuine altitude compensation kit described below. The ultimate users of SI engines must comply with the regulations through the installation of the appropriate altitude compensation kit for the altitude range where the engine will be operated.
Altitude Compensation Kit
Original carburetor
(with 0 m kit)
0 m
0 ft
1000 m compensation kit
2000 m compensation kit
Applicable Altitude Ranges
700 m
2300 ft
300 m
1000 ft
1300 m
4300 ft
1700 m
5600 ft
2700 m
8900 ft
*) Prepare for the users who have lost original carburetor’s jet.
Altitude compensation kit part number: Please contact your local KUBOTA dealer and specify your engine type and engine serial No.
Please consult your local KUBOTA dealer for further information on the altitude compensation kit.
CONSULT YOUR LOCAL KUBOTA DEALER FOR FURTHER INFORMATION ON THIS
PROCEDURE.
LPG FUEL SYSTEM AND DIAGRAMS (DF752-E2)
Never use LPG fuel on the WG752-E2 engine. Otherwise severe damage will occur.
¡ All fuel connections added to this engine must be installed by qualified personnel and utilizing recognized procedures and standards.
¡ These non-KUBOTA installed parts, such as hoses, fittings, piping and shut off solenoid valve should be approved for LPG use and conform to UL, CSA, NFPA, MSHA and all other applicable standards.
¡ An approved, listed fuel filter and shut off solenoid valve must be installed between the LPG tank and KUBOTA LPG regulator with vaporizer.
쏋 TIGHTENING TORQUES AND LEAK CHECK FOR LPG REGULATOR WITH VAPORIZER
(1) Each fitting must be sealed with approved joint sealant compound, and be tightened to the specified torque using a wrench and leak check must be performed as show in the below table.
[TIGHTENING TORQUE AND LEAK CHECK PRESSURE]
FITTING
LPG OUT (VAPOR)
LPG IN (LIQUID)*
WATER IN/OUT
Qty.
1
1
2
SIZE
PT-3/8
PT-1/4
PT-3/8 tightening torque
N·m
29.4~58.8
19.6~39.2
29.4~58.8
kgf·m
3.0~6.0
2.0~4.0
3.0~6.0
ft-lbs
21.7~43.4
14.5~28.9
21.7~43.4
kPa leak check press.
> 9.8
> 1471
> 245 kgf/cm 2
> 0.1
> 15
> 2.5
psi
> 1.42
> 213
> 35.6
* NOT KUBOTA supplied
(2) CHANGE THE ANGLE OF LPG FITTING OF DUAL FUEL CARBURETOR
The fitting on the dual fuel carburetor may be mounted on any position since is not sealed.
The nut may be loosened using a wrench.
LPG fitting may be changed to any specified angle.
The nut should be tightened to the specified torque using a wrench as shown in the below table.
[TIGHTENING TORQUE]
FITTING
LPG IN(VAPOR)
Qty.
1
SIZE
M12 쎹1.25
tightening torque
N·m
11.8~26.5
kgf·m
1.2~2.7
ft-lbs
8.7~19.5
leak check soap solution or its equivalent
쏋 SETTING OF LPG REGULATOR AND VIBRATION LIMITS
Install the LPG regulator in UPRIGHT position as shown in below A marking figure.
It must be installed within 4G vibration level. If not, it may not supply necessary LPG fuel to the engine.
(See “PRE-OPERATION CHECK, w FUEL, LPG” section)
TAMPER RESISTANCE
¡ Carburetor (WG752-E2), Dual fuel carburetor (DF752-E2)
The carburetor is tamper resistant; the idle mixture screw has been covered by tamper plug after adjustment at the factory.
You CANNOT adjust this screw.
¡ Distributor
The distributor is tamper resistant; the ignition timing adjustment screw has been covered after adjustment at the factory.
You CANNOT adjust the ignition timing.
WIRING DIAGRAMS
¡ LPG regulator (DF752-E2)
LPG regulator is tamper resistant; the main and idle pressure adjustment screws have been covered by tamper caps after adjustment at the factory.
You CANNOT adjust the above 2 screws.
If service or repair is needed, contact your local KUBOTA dealer.
q ENGINE OIL
쏋 Checking oil level and adding engine oil.
(1) Detach the dipstick, wipe it clean, reinsert it, take it out again, and check the oil level.
(2) Add engine oil if necessary. Engine oil level within this range A is proper.
IMPORTANT :
Engine oil should meet as a minimum SAE viscosity and SH class grades (API classification).
Change the engine oil according to the ambient temperature, expected between changes.
above 77 °F
32 °F to 77°F
32 °F to 0°F
SAE30 or 10W30
SAE20 or 10W30
SAE10W or 10W30 w FUEL
쏋 Gasoline
1. Use unleaded gasoline only.
¡ DO NOT use gasoline blended with methyl alcohol.
쏋 LPG (DF752-E2)
1. Use Commercial LPG only.
2. Fuel tank is liquid withdrawal type.
IMPORTANT :
¡ Be sure that the fill up valve and the liquid withdrawal valve are closed.
¡ Be sure that LPG hose is connected with the liquid withdrawal valve.
¡ Be sure that LPG tank is placed firmly not to move by machine vibration.
(See “LPG FUEL SYSTEM AND DIAGRAMS” section.)
PRE-OPERATION CHECK
e RADIATOR
3 WARNING :
To avoid personal injury :
¡ Do not touch or remove radiator cap when engine is hot !
쏋 Checking level, adding and changing coolant.
(1) Remove the radiator pressure cap and check to see if coolant reaches the supply port.
(2) To prevent possible coolant problems to the engine, always assure a 50% / 50% anti-freeze and H
2
O mixture regardless of temperature.
Use only ethylene glycol or propylene glycol type anti-freeze for this engine.
(3) In case of loss of coolant, add the appropriate amount of 50% / 50% mixture of anti-freeze and water. In addition, check two drain cocks at the lower position of the radiator and the side of the crankcase to see if they are securely tightened.
(4) Change anti-freeze and H
2
O mixture once a year.
r BATTERY
Checking the electrolyte level.
¡ The electrolyte level drops as water evaporates.
Excessively low electrolyte level can damage the battery.
¡ Be sure to add only distilled water.
¡ Be sure to wear protective clothing and safety glasses when checking battery condition !
IMPORTANT :
¡ When there is a fear of the temperature dropping below 5°F (–15°C) detach the battery from the machine, and keep it in doors to be reinstalled just before the next operation.
STARTING THE ENGINE
Gasoline q Open the fuel cock of the gasoline line.
LPG q Open the liquid withdrawal valve of the LPG fuel tank.
w Turn the fuel selector switch* to the
“Gasoline” position. (DF752-E2) w Turn the fuel selector switch* to the
“LPG” position. (DF752-E2)
* Not KUBOTA supplied the fuel selector switch.
See “WIRING DIAGRAMS” section about the wiring.
e Set the speed control lever to “low idling”.
i
Gasoline
If the engine is started, open the choke lever gradually (move the lever to the
“OPEN” position).
i
LPG
Do not move the choke lever, when
LPG starting.
o Check to see that the oil pressure lamp and charge lamp are OFF.
If not, immediately stop the engine and check the cause.
!0
Warm up the engine at medium speed running for 3 to 5 minutes.
IMPORTANT :
(1) NEVER turn the starter switch while the engine is running.
(2) Be sure to warm up the engine not only in winter but also in other warmer seasons.
(3) In case of converting the fuel (gasoline ,/ LPG) while running the engine, the engine should be operated with the engine speed high and no-loaded. If you convert the fuel with the engine speed low, the engine will stop. (DF752-E2) r Move the choke lever to the
“CLOSED” position.
r DO NOT move the choke lever, when
LPG starting.
STOPPING THE ENGINE
q
Gasoline
Disengage the engine drive power and set the speed control lever to
“low idling”.
LPG t Insert the key into the starter switch and turn it to the “ON” (') position.
y Check to see that the oil pressure lamp and charge lamp are ON.
u Turn the key to the “START” position and the starter will begin turning. Release the key immediately, when the engine starts.
w Close the fuel cock of the gasoline line.
e Cool down the engine for 2 to 3 minutes.
w Close the liquid withdrawal valve of the LPG fuel tank.
r Turn the starter switch to the “OFF”
( 쎲) position.
Remove the key at the “OFF” position.
MAINTENANCE / CHECKING SCHEDULE
In order to keep your engine in good working conditions, be sure to follow the maintenance / checking schedule given in the table below.
(The schedule applies to an engine in use under normal conditions.)
Item
Each parts
Engine oil
Oil filter cartridge
Spark plug
Ignition wires
Air cleaner element
Intake pipe / clamp bands
Fuel filter
Fuel tank
Fuel pipe /clamps
(Gasoline line)
Fuel pipe / clamps
(LPG line : LPG tank~
Dual carburetor)
Carburetor
LPG vaporizer regulator
Battery
Radiator coolant
Radiator hoses and clamp bands
Interval
Every
8 hours
(daily)
Every
50 hours
(weekly)
Every
100 hours
Every
200 hours
Every
1000 hours
Yearly
Each
2 years
Check / Clean
Check / Replenish
쎲
쎲
Change
Change
(Intail change)
(Intail change)
쎲
쎲
Clean
Adjust
쎲
왖
Change 쎲
Change 쎲
Check
Clean
왖
왖 쎲
Change 쎲* 1
Change 쎲
Check / Clean 쎲
Change
Clean
쎲
쎲
Check setting 왖 쎲
Check 쎲
Change 쎲
Check the connector 쎲
Check fuel leakage 쎲
Change 쎲
Clean 쎲
Check 쎲
Change
Check inner parts* 2
쎲
쎲
Check 쎲
Change 쎲
Check 쎲
Change 쎲
Check 쎲
Change 쎲
Radiator and water jacket Clean 쎲
Fan belt tension
Check
Adjust
쎲
왖
Valve clearance
Cylinder head
Valve seats
Adjust
Clean
Check / relap
쎲
쎲
쎲
왖 : If necessary
* 1 Change more often when operating under dusty conditions.
Remarks &
Ref. Item No.
Gasoline line
LPG line
Hot water line / vacuum lock pipe
Hot water line / vacuum lock pipe
3
4
5
2
8
7
10
9
6
6
6
1
* 2 If necessary, contact your local KUBOTA dealer.
To keep your KUBOTA performing for many years of service, use only genuine KUBOTA replacement parts.
zDF752-E2x
MAINTENANCE
BREAK-IN :
During the engine break-in period, observe the following.
(1) Change engine oil and oil filter cartridge, after the initial 50 hours of operation.
(2) When the ambient temperature is low, only operate the machine after the engine has been completely warmed up.
PERIODIC SERVICE :
(1) FAN BELT – Adjustment of tension
An improperly adjusted fan belt can cause engine over-heating and insufficient battery charging.
Push on the fan belt at the middle with a finger and check that it deflects about 10 mm (0.4 in.).
(2) AIR CLEANER – Cleaning of element & Replace q The element used on this engine is a dry type and so do not apply oil to it.
w When dry dust adheres to the element, blow compressed air from the inside turning the element, pressure of compressed air must be under 205 kPa (2.1 kgf/cm 2 , 30 psi).
e Replace the element every year or every six cleanings.
r Install the air cleaner dust cup with “TOP” indicated on the rear of the cup.
t Do not over-service the air filter element.
(3) ENGINE OIL – Changing engine oil q Place an oil pan under the engine. Remove the drain plug at the bottom of the engine, and drain all the old oil. Draining oil will be easy and complete if done while the engine is still warm.
w Supply new engine oil up to the upper limit of the dipstick.
(4) OIL FILTER CARTRIDGE – Replacing q Remove the oil filter cartridge with a filter wrench.
w Apply a film of oil to the gasket for the cartridge.
e Screw in the cartridge by hand. When the gasket comes in contact with the seal surface, tighten the cartridge enough by hand.
(5) SPARK PLUG – Cleaning & Ajustment clearance
If the spark plug electrode or its insulator is soiled or is covered with deposited carbon, it may cause engine trouble. The soil, carbon deposits etc. can be brushed off using a wire brush.
After cleaning, be sure to adjust for proper clearance.
(6) RADIATOR q In the event of insufficient coolant, fill the radiator with a 50% / 50% mixture of antifreeze / H
2
O and check.
If radiator is equipped with a coolant recovery tank, fill this tank also to the level indicated on the tank.
w Never use muddy or sea water as coolant.
e Be sure to tighten the radiator pressure cap securely after supplying coolant.
쏋 Checking radiator hoses (water pipes)
1.
Check to see the radiator hoses are properly fixed every 200 hours of operation or six months, whichever comes first.
q If clamp bands are loose and water leaks, tighten bands securely.
w If radiator hoses are swollen, hardened or cracked, replace hoses and tighten clamp bands securely.
2.
If checked and found that hoses are swollen, hardened or cracked, replace hoses and clamp bands every 2 years or earlier.
(7) LPG LEAKAGE CHECK (for DF752-E2)
Turn on the gas at low idling rpm and use a soap solution or its equivalent to check all connections for leaks between the fuel tank and dual fuel carburetor.
Bubbles will indicate a loose connection.
3 WARNING : NEVER TEST FOR GAS LEAKS WITH A FLAME.
(8) LPG FUEL TANK CHECK (for DF752-E2)
Check that LPG fuel tank is installed firmly.
Be sure that the fill up valve and liquid withdrawal valve of the LPG fuel tank can be opened and closed easily.
(9) LPG REGURATOR CHECK (for DF752-E2)
Check that the hot water lines are not leaking.
Check that the vacuum lock pipe is not damaged.
(10) CARBURETOR CHECK
Clean and check for leakage. Check throttle plate for dirt.
