DIESEL ENGINE | 68mm STROKE SERIES (NSM SERIES)TO THE READER This Workshop Manual has been prepared to provide servicing personnel with information on the mechanism, service and maintenance of KUBOTA Diesel Engine 68 mm STROKE SERIES. It is divided into two parts, “Mechanism” and “Disassembling and Servicing”. 1 Mechanism Information on construction and functions are included for each engine section. This part should be understood before proceeding with trouble- shooting, disassembling and servicing. Disassembling and Servicing Under the heading “General” come general precautions, troubleshooting, lists of servicing specifications and periodic inspection items. For each engine section, there are "Checking and Adjustment”, "Disassembling and Assembling”, and “Servicing” which cover procedures, precautions, factory specification and allowable limits. | | All the engines that have been menufactured since January of 1994 are clean exhaust engines, ‘The mark [E] in the WSM refers to the said clean engine. All information, illustrations and specifications contained in this manual are based on the latest production information available at the time of publication. The right is reserved to make changes in all information at any time without notice. July 1990 © KuBoTA Corporation 1990CONTENTS SAFETY INSTRUCTIONS. 1 PERFORMANCE CURVES: 5 ‘SPECIFICATIONS 4 DIMENSIONS. 7 M. MECHANISM F. FEATURE M1 {2] WATER PUMP M9 1, ENGINE BODY, M2 [3] THERMOSTAT -- + M10 [1] CYLINDER BLOCK M2 [4] RADIATOR M10 [2] CYLINDER HEAD M2 [5] RADIATOR CAP M-10 [3] CRANKSHAFT M3 FUEL SYSTEM M11 [4] PISTON AND PISTON RINGS oe MB [1] GENERAL -. M11 [5] CONNECTING ROD see M3 [2] FUEL FILTER - (3) FUEL FEED PUMP ~~ [a] INJECTION PUMP [5] INJECTION NOZZLE : [6] GOVERNOR - M5 5. ELECTRICAL SYSTEM [6] CAMSHAFT [7] FLYWHEEL - [8] ROCKER ARM [9] VALVE TIMING ..... 2, LUBRICATING SYSTEM [1] GENERAL ees ~ M5. [1] STARTING SYSTEM [2] oi uM 7 [2] CHARGING sYsTeM (3]_ RELIEF VALVE -- MAT Tal OIL FILTER CARTRIDGE [5] OIL PRESSURE SWITCH 3. COOLING SYSTEM: [1] GENERAL- S. DISASSEMBLING AND SERVICING G. GENERAL. [1] ENGINE IDENTIFICATION [2] GENERAL PRECAUTIONS [3] TIGHTENING TORQUES [4] TROUBLESHOOTING {5] SERVICING SPECIFICATIONS [6] MAINTENANCE CHECK LIST [7] CHECK AND MAINTENANCE - [8] SPECIAL TOOLS «nn S41 DISASSEMBLING AND ASSEMBLING .. 1 SERVICING 1 [1] ow pump 3. COOLING SYSTEM CHECKING AND ADJUSTING $6 [1] FAN BELT- S12 [2] RADIATOR. 13 {3] THERMOSTAT DISASSEMBLING AND ASSEMBLING 1. ENGINEBODY. [1] THERMOSTAT AND WATERPUNP CHECKING AND ADJUSTING 4. FUEL SYSTEM: DISASSEMBLING AND ASSEMBLING $26 CHECKING AND ADJUSTING [1] DRAINING WATER AND Oll [1] INJECTION NOZZLE —- [2] EXTERNAL COMPORNENTS [2] INJECTION PUNP - [3] CYLINDER HEAD AND VALVES - DISASSEMBLING AND ASSEMBLING [4] TIMING GEAR AND CAMSHAFT: [i]. INJECTION NOZZLE neon SSBB [5] PISTON AND CONNECTING ROD ~ 5, ELECTRICAL SYSTEM {6] FLYWHEEL AND CRANKSHAFT CHECKING - SERVICING - [1] DYNAMO AND REGULATAR - ~ [1] CYLINDER HEAD AND VALVES 2) STARTER = [2] PISTON AND CONNECTING ROD S42 [3] GLow PLUG [3] TIMING GEAR AND CAMSHAFT DISASSEMBLING AND ASSEMBLING [4] CRANKSHAFT (1) STARTER [5] CYLINDER. SERVICING «= 2. LUBRICATING SYSTEM [1] STARTER CHECKING --SAFETY INSTRUCTIONS. ‘Gomm STROKE SERIES WSMO2400 this unit, This symbol, the industry's “Safety Alert Symbol”, is used throughout this manual and on labels on ‘the machine itself to warn of the possibility of personal injury. Read these instructions carefully. itis essential that you read the instructions and safety regulations before you attempt to repair or use 4A SAFETY FIRST A warninc Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury. :Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. IMPORTANT == NOTE Indicates that equipment or property damage could result if instructions are not followed. BEFORE SERVICING AND REPAIRING * Read ail instructions and safety instructions in this 3 manual and on your engine safety decals. Clean the work area and engine. Park the machine an a firm and level ground, Allow the engine to cool before proceeding. Stop the engine, and remove the key. Disconnect the battery negative cable.‘65mm STROKE SERIES WSH,02400 SAFETY INSTRUCTIONS, SAFETY STARTING * Do not start the engine by shorting across starter terminals or bypassing the safety start switch. ( * Unauthorized modifications to the engine may impair the funetion and / or safety and affect engine ite. SAFETY WORKING * Do not work on the machine while under the influence of alcohol, medication, or other substances or while fatigued, * Wear close fitting clothing and safety equipment Be, ‘appropriate to the job. lt ie * Use tools appropriate to the work. Makeshift tools,( Parts, and procedures are not recommended. * When servicing is performed together by two or more persons, take care to perform all work safely * Do not touch the rotating of hot parts while the engine is running. + Never remove the radiator cap while the engine is running, or immediately after stopping. Otherwise, hot water will spout out from radiator. Only remove radiator cap when cool enough to touch with bare hands. Slowly loosen the cap to first stop to relieve pressure before removing complotely, . + Escaping fluid (fuel or hydraulic oil) under pressure can penetrate the skin causing serious injury. Relieve pressure before disconnecting hydraulic or fuel lines. Tighten all connections before applying pressure. ‘eh * Wear a suitable heating protective device such as earmutts or earplugs to protect against objectionable or uncomfortable loud noises. ( AVOID FIRES * Fuel is extremely flammable and explosive under certain conditions. Do not smoke or allow flames or sparks in your working area. * To avoid sparks from an accidental short circult, always disconnect the battery negative cable first and connect it last. + Battery gas can explode. Keep sparks and open flame away trom the top of battery, especially when charging the battery. —M t Spilled on the engi| SAFETY INSTRUCTIONS ‘GBmm STROKE SERIES WSM,02400 VENTILATE WORK AREA + Ifthe engine must be running to do some work, make sure the area Is well ventilated. Never run the engine ina closed area. The exhaust gas contains poisonous carbon monoxide. DISPOSE OF FLUIDS PROPERLY * Do not pour fluids into the ground, down a drain, or into a stream, pond, or lake. Observe relevant environmental protection regulations when disposing ot ol, fuel, coolant, electrolyte and other harmful waste. PREVENT ACID BURNS + Sulfuric acid in battery electrolyte is poisonous. tt is strong enough to burn skin, clothing and cause blindness if splashed into eyes. Keep electrolyte away from eyes, hands and ciothing. if you spill electrolyte on yourself, flush with water, and get mecical attention immediately. PREPARE FOR EMERGENCIES ‘+ Keep a first aid kit and fire extinguisher handy at all times. + Keep emergency numbers for doctors, ambulance service, hospital and fire department near your telephone.Semm STROKE SERIES WSN,02400 SPECIFICATIONS SPECIFICATIONS Mode! 2a42-B(e) 2482-8 (E) 662-8 (E) 722-8(6) Type ‘Vertical liquid cooled, cycle diesel engine Number of Cylinders 2 2 3 3 Bore xStroke mm(in} | 64x68 (2.52268) | 67x68 (2.64%2.68) | 64x68(2.52%2.68) | 67x68 (2.64x2.68) Total Displacement eCleu.in) | _a37 (26.70) 479 29.23) 656 (40.05) 719 (43.89) sees, 7.5kW/3600"pm [8.1 kW3600 rom | 11-2kWARGOOrpm | 122KWIA600 rpm 10.04°73600rpm_|10.8HPA600rpm | 15.0HP96001pm_ | 16.3HP/3600 rpm SAE Net intermittent H. 8.6kW/3600rpm | 9.3kW/2600 rpm | f29kWA600¢xm | 14,0KW/S600rpm 7 Tispacoorem | t2snrasoorpm | t/anpacoorem | tSoNraebo ren 8 [secon ‘35KWa600 rpm | 10.AKWAGODrpm | \42KWE0O pm | 15 6KWAGOO pm & [renee iz7ueacoorpm | 139ueaso0rpm | tezuerscoorgm | r0oNrass0 rem 3 T 7AkwaG00 con | —7.skwa600 em | 110KWAs00rmm | ~12,1K4/A600 pm 2 DIN6271-NA 10.0 PS/3600 rpm 10.8 PS/3600 rpm 15.0 PS/3600 rpm 16.4 PS/3600 rpm : E2KWAEOOr=m | _B9KWAEOOr|m | 123KW/8600 pm | 1a.3KWA60O rom DING27I-NB 11,1 P5/3600 rpm_ 12.1 PS/3600 rpm 16.7 PS/3600 rpm 48.1 PS13600 rpm : e9KWAe00 em | a7 KwAEOOrM | 13SKWAGIO~GM | TA SEWAEO em DIN70020 12.1 PS/3600 rpm 13.2 PS/3600 rpm 18.3 PS/3600 rpm 19.9 PS/3600 rpm ‘Maximum Bare Speed 3800 rpm ( Tinimum Bazelding Speed 36 800 Combustion Chanter ‘Spherical type Fuel injection Pump ‘Bosch MD mini Pump ‘Governor Centrifugal Ball Mechanical Governor Direction of Roterion ia Injection Nozzle ‘Counter-clockwise (viewed from flywheel) Bosch Throtte Type Tnjection Timing (0.35 100.38 rad. (20°20 27") before TD.G Injection Order 2 12 123 1 Injection Pressure 13.73 MPa (140 kgifem?, 199% pal) Compression Ratio BH Lubricating System Forced Lubrication by Pump il Pressure Indication Electrical Type Switch lubricating Fitter Full Flow Paper Filter (Cortidge Type) ‘cooling system Pressurized Radiator (notincluded in the basic model), Forced ‘ulation with Water Pump Starting System cic Starting With Cel'sarter 12V,_O8kW Starting Support Device bby Glow Plugin Combustion Chamber Battery 12V,35AH, equivalent Generetor for Charging TRV, 150W Fuel Diesel Fuel NOD (ASTIADETE) (iass GF ibricating il as per AP clasilcalion erecormondod. Lubricating oi I is classof bleating o's aot aval, profeably uso Clase CD or CE lubricating o For detls on recommended tubeatng dl, £89 page S-12, 15. Lubricating Oi Capecity 2.1 (22 US.as. 1.85 imp. gto) 3.218.405, 251 Imp. at) = PO USS, 33TIMp- aU) Weight Om) sang cii7aie) [ s3rkg (117.1109) | ea7kg 404s) | 63.149 (199.1) ‘pplication General Power SourcePERFORMANCE CURVES ‘Gémm STROKE SERIES WSN,02400 . PERFORMANCE CURVES im 7492-8 (6) 7482-8 (€) (SAE) (SAE) fate Hpz 3.0 he [2s 14 =o) Hla 20 13 13] fo 12 12 | 3 2 " " 7 1 up i ® 3 D ® 8 8 {eo Cis 7 7 f itis 6 sy iti Tris 2® 5 5 Ga (210 4 04a poe = = 0.42 hao 16 15 20 22 24 26 2% 30 32 38 36 ‘pmX100 a an F001 6003 ayy Ett 2 1 " P59) ® 3 0; 1 a mh x r ite i 6 : itg® 6 s ‘ 240 Ss: 4 pif ttt boo a aT esrewn | FP They L Lyi E 16 ¥8 20 32 8 26 30 30 92 30 36 V6 te 20 22 20 26 26 30.97 8 36 A116F002 spmx100_Q) Atieroo4 spnxioo @) () Brake Horsepower (7) NetCom. Torque @) Engine Speed {@) Gross intermittent 9. @) BSF {9) Net intermittent 8.4? (@) Torave (0) Net cont BHP {5) Gros interittent Torque (11) BSC ANetintermittent) (6) Netintermitent TorqueGarne STRORE SERIES WSM 02400 PERFORMANCE CURVES, m 0662-816) 722-8 (E) (SAE) (SAE) 32 35/5 ba 3 a 20 [4 Bo f © 2a |, ® ne ly bo 2» re 2» os 19) 55 a 52 16 16 He fo o™ oy a | 19 a4 10 z i Le £@ 7 25 8 5 1-45 200 as, . {ise ° rise ~ l.aolre0 + FEA ‘volte Wei0 20 2 We 36 18 BO HT EH 16 18 20 22 20 2696 36 3330 6 ‘omxio0 @) 190x109" @ Avi6r005 ‘a116F007 ny TIN) E = - a0 a0 a0 [a B8o fo 30 Go 30 bo 20) § & ge r 2? Be 16 *s o. a ad wot ia rt . Z ie 4 EES Ey iv 200 BS F.C 200 él Kasecine)— 290 7 : ae a0 180 Wis 20 22 24 26 28 30 3234 36 se ia 30-2298 26 18 3099 3a 36 ‘pmxt00 pmx 100 Aiooroos 2 An16F008 ® (0) Brake Horsepower (7) Net Cont. Torque {2) Engine speed {@) Gross Intermittent a. @) asre 9) Hetintermitent BHP. (10) Net Cont. 8.4. (8) Torque (11) BSE. (Netintermittent) (8) Gross intermittent Torque (6) Not Intermitent Torque~ DIMENSIONS, . DIMENSIONS ‘anm STROKE SERIES WSM,02400 este © | 0662-8 (€), 0722-8 (E) 7462-8 (E), 2482-8 (E) Unit: mm (in) penis cee a [- em = Sasi j) eh | Lanter 4 ar § 3 i 7" - 28 rel te 767 esaa0 Ann6r010 ‘116009 = Be 1 Te 4 g 4 | | SEleens TS) ‘ANN6FOOS ATTSFOTTBarnm STROKE SERIES WSM,02400, DIMENSION! Wi 2442-8 (E), 2482-8 (E) Unit: mm (in) 1662-6 (E), D722-B (E) A: 16a. (0.63 da) 8:25.Adia.(100dia) 21047) 4030) in f03 ha 89) 926.62) Psiniestclal “SS Sia (0.35dia) N3place dia (0.35¢i0) o foo oh 0.06) icy S 2/3 ‘al 2/3 53 3 ae qq ag Sha] a ai)a 3 POO} a Sas! Sor 5) A a SSH : tae | ‘place S a ] $2dia.0 3240) ma —— | 7H12(0.47 place | { ee “Te dia. (0 35410) 9362 | oF 6n | 65020! [laser 35492) 0151.18) anieroa1 anneroz"RUF FEATURE FEATURE ‘omni STROKE SERIES WSMOZ400 ov09F011 or09F0r2 ‘The 2442-8, 7482-B, D662-B, D722-B are vertical, liquid-cooled, 4-cycle diesel engines. They incorporate KUBOTA’s foremost technologies. With KUBOTA’s the "NTVCS” (New Three Vortex Combustion System), well-known Bosch MD mini type injection pump and the well-balanced desi ive gr w fuel consumption, little ion and quiet operation. Ma MNOTE © Since January 1994, E-TVCS has been used for the combustion chamber of our products instead of traditional N-TVCS. E-TVCS was developed with an eye toward clean exhaust gas which is more environmentally after refers to E-TVCS. Model of combustion chamber NYG (En jine Serial Number ; 489290 or lower) E-TVCS (Engine Serial Number ; 489291 or higher)Garam STROKE SERIES WSM,02400 El ENGINE Bopy [1] CYLINDER BLOCK 01724007 [2] CYLINDER HEAD —8| 109014 09874009 Oo M1 ENGINE BODY The engine has a high durability tunnel-type ‘ylinder block in which the crank bearing component is a constructed body. Furthermore, liner less type, allow effective cooling, less distortion, and greater wear-resistance. The noise level is reduced to a minimum because each cylinder has its own chamber. The cross-flow type intake/exhaust ports in this engine have their openings at both sides of the ports are smailer than in ports of other types which have openings on one side, the suction air can be protected from being heated and expanded by heated exhaust air. The cool, high density suction air has high volume efficiency and raises the power of the engine. Furthermore, distortion of the cylinder head by heated exhaust gas is reduced because intake ports are arranged alternately. The combustion chamber is of KUBOTA’s exclusive New TVCS combustion chamber type. Suction air is whirled to be mixed effectively with fuel, prompting combustion and reducing fuel consumption, In the combustion chamber are installed throttle type injection nozzle and rapid heating sheathed type glow plug. This glow plug assures easier than ever engine starts even at -15°C (5) o @ @ a “ © ” & ° Combustion Chamber Intake Port Exhaust Port Nozzle Assembly Glow Plug, Cylinder Head Fan-shaped Concave Stream Air tnlet Combustion System These engine use the "NTVCS" (New Three Vortex Combustion System) to achieve perfect combustion for maximum power. The NTVCS combustion system provides unique shape of throat in the air inlet (9) for combustion chamber, to produce three streams (8) of air in the chamber (1) when compressing, giving an ne) ® 00877010 ture of airand fue In addition, a fan-shaped concave (7) is provided on top of the piston to allow a smooth ejection of the exhaust gas, offering highly efficient combustion.“> M.A ENGINE BODY, - [3] CRANKSHAFT 0087011 ‘Genin STROKE SERIES WSN, 02400 The crankshaft with the connecting rod converts the reciprocating motion of the piston into the rotating motion. The crankshaft is made of tough special alloy stee!, and the journals, pins and oil seal sliding portions are induction hardened to increase the hardness for higher wear resistance. The front journal is supported by a solid type bearing, the intermediate journal by a split type, and the rear journal by a split type with thrust bearings. The crankshaft is provided with an oil gallery, through which engine oil is fed to the crank pin portion, and lubricate it 4] PISTON AND PISTON RINGS The piston is made of aluminum alloy. Two recesses for the valves are provided on top of the piston. A fan-shaped depression is also given atop the piston in order to allow combustion gas to jet smoothly. The piston pin is slightly out of the a: : m <0 Re a ar o109F017 piston at the top and bottom dead points can be reduced, thereby resulting in lower operating noise. The piston has a slightly oval shape when cold (in consideration of thermal expansion) and a concave head. ‘Three rings are installed in grooves in the piston. The top ring (1) is a keystone type, which can stand ‘against heavy loads, and the barrel face on the ring (0087F013 fits well to the cylinder wall ‘The second ring (2) is an undercut type, which effectively prevents the oil from being carried up. The oil ring (3) has chamfered contact faces and an expander ring, which increase the pressure of the oil ring against the cylinder wall Several grooves are cut on the topland to help heat dissipate and to prevent scuffing, O} Q) Q) 7 6) Top Ring Second Ring Oil Ring Fan-Shaped Concave valve Racess [5] CONNECTING ROD Connecting rod (2) is used to connect the piston with the crankshaft. The big end of the connecting rod. has a crank pin bearing (3) (split type) and the small end has a small end bushing (1) (solid type). (1) Smallnd Bushing (2) Connecting Rod @) Crank pin Bearing ov09F018 M3‘Gorim STROKE SERIES WSM.02400 i,t ENGINE BODY [6] CAMSHAFT The camshaft (3) is made of special cast iron and the journal and cam sections are chilled to resist wear. The journal sections are force-lubricated. The fuel camshaft (5) controls the reciprocating movement of the injection pump. The fuel camshaft is made of carbon steel and the cam sections are quenched and tempered to provide greater wear resistance. (1) Cam Gear (2) Injection Pump Gear (2) Camshaft Stopper (6) FuelCamshatt () Comshatt A116F019 7] FLYWHEEL The flywheel stores the rotating force in the combustion stroke as inertial energy, reduces crankshaft rotating speed fluctuation and maintains the smooth rotating conditions. ‘The flywheel periphery is inscribed with the marks showing top dead center mark TC. fiywheel has gear teeth around its outer ti ‘which mesh with the drive pinion of the starter. 1) Crankshaft @) Flywheel Scrow ) Flywheel ov09F023 [8] ROCKER ARM 7 The rocker arm assembly includes the rocker arms gat® | (1), rocker arm brackets (@) and rocker arm shaft (5) 7) and converts the reciprocating movement of the push rods to an open/close movement of the inlet ‘and exhaust valves a Lubricating oil is pressurized through the bracket to the rocker arm shaft, which serves as a fulcrum so wr, that the rocker arm and the entire system are ms lubricated sufficiently. es we (1) Rocker Arm (@) Rocker Arm Bracket A Q) tock Nut 18) Rocker Arm Shatt (3) Adjusting Serew o109F021 9] VALVE TIMING The timing for opening and closing the valve is Dp ® extremely important to achieve effective air intake and sufficient gas exhaust. ‘The appropriate timing can be obtained by aligning the marks on the crank gear and the cam. gear when assembling, oe inlet valve open ‘O35 rad QO) before TDG inlet valve cose 079 ad. (5% after BOS Exhaust valve open @ D7 rad. (50% before S.C 5 Exhaust valve dove ® O26 rad. (SM alter TOG. ono7rozr M4M2 LUBRICATING SYSTEM. LUBRICATING SYSTEM [1] GENERAL (GBmm STROKE SERIES WW, 02400 ) o109F024 IA} ollPump Ic] Rocker Arm and Rocker Arm Shaft LE] Comshatt [8] il strainer ID} Piston This engine’s lubricating system consists of oil strainer, oil pump, relief valve, oil filter cartridge and oil switch. The oil pump sucks lubricating oil from the oil pan through the oil strainer and the oil flows down to the filter cartridge, where it is further filtered. Then the oil is forced to crankshaft, ‘connecting rods, idle gear, camshaft and rocker arm TF] Oilrilter Cartridge and Reliet valve shaft to lubricate each part. Some part of oil, splashed by the crankshaft or leaking and dropping from gaps of each part, lubricates these parts: pistons, cylinders, small ends of connecting rods, ‘tappets, pushrods, inet and exhaust valves and timing gears. M5‘86mm STROKE SERIES WSM,02400 1.2 LUBRICATING SYSTEM 01077025 = Engine Oil Fiow 1) OllPan () Bigend (16) Tappets @) Ollstrainer (10) Timing Gear (17) Camshaft Beering @) on1Fump. (11) splash (18) Camshaft @) Relief Valve (12) Bore (19) Drain (6) Oilfiter Cantidge (13) Smallend (@0} Rocker Arm © ‘dle Gear (14) Piston 21) O’switch (7) Main OllGolery (13) Fuel Camshaft (22) Rocker Arm Shaft ® M6” M2 LUBRICATING SYSTEM {2] O1L PUMP Port @) OutletPort @) Inner Rotor (@) OvterRotor ‘Gémm STROKE SERIES WOM 02400 ‘The oil pump is a trochoid pump, whose rotors have trochoid lobes. The inner rotor (3) has 4 lobes and the outer rotor (4) has 5 lobes, and they are eccentrically engaged with each other. The inner rotor, which is driven by the crankshaft through the gears, rotates the outer rotor in the same direction, varying the space between the lobes. While the rotors rotate from (A) to (8), the space leading to the inlet port increases, which causes the vacuum to suck in the oil from the inlet port. When the rotors rotate to (C), the space between both rotors switches from the inlet port to the outlet port. At (O), the space decreases and the sucked oil is discharged from the outlet port. {3} RELIEF VALVE 0109026 The relief valve prevents the damage to the lubricating system due to the high pressure of the oil The relief valve is ball direct acting type, and is best suited for low pressures. When the pressure of the oil, forced by the pump, exceeds the specified value, the oil pushes back the ball (2) and escapes to the oil pan. (1) Spring 2) Ball (@) Valve Seat ‘ {A} OIL FILTER CARTRIDGE After lubricating, the lubricating oil brings back various particles of grit and dirt to the oil pan. Those particles and the impurities in the lubricating oil can ‘cause wear or seizure of the engine parts. it may also impair the physical and chemical properties of the oil itself The lubricating oil which is force-fed by the pump, is filtered by the filter cartridge with the filter element. (2). When the filter element accumulates on excessive amount of dirt and the oil pressure in the inlet line builds up by 98 kPa (1.0 kgffem2, 14 psi) more than the outlet line, the bypass valve (1) opens to allow the oil to flow from the inlet into the outlet ‘07 09FOR DIOsFOZe Tine, bypassing the filter element. (1) Bypass Valve 2) Fier Element‘Gorn STROKE SERIES WM 02400 M.2 LUBRICATING SYSTEM [5] OIL PRESSURE SWITCH ‘The oil pressure switch is mounted on the cylinder block and is led to the lubricating oil passage. When the oil pressure falls below the specified value, the oil pressure warning lamp lights. IA] Atthe propercoilpressure {8} Atlower oil pressure, 49 ra (0.5 kgtiem2,7 psi) or less (1) Terminal 45) Contactevet Q) insulator 16) Contact @) Spring (7) OiSwiten Body (4) Rubber gasket or07#029 M8. M3 COOLING SYSTEM -E1 COOLING SYSTEM ‘damm STROKE SERIES WSM,02400 [1] GENERAL (1) Radiator {@) Suction Fan {@) Thermostat q ? {@) Water Pump \ LG i yn anon 8083F248 sa The cooling system consists of a radiator (1) (not included in the basic engine), centrifugal water, pump (A), suction fan (2) and thermostat (3). The water is cooled through the radiator core, and the fan set behind the radiator pulls cooling air through the core to improve cooling, The water pump sucks the cooled water, forces it into the cylinder block and draws out the hot water. [2] WATER PUMP @ @ Then the cooling is repeated. Furthermore, to control temperature of water, a thermostat is provided in the system. When the thermostat opens, ‘the water moves directly to radiator, but when it closes, the water moves toward the water pump ‘through the bypass between thermostat and water pump. The opening temperature of thermostat is approx. 71°C (160°F).. The water pump is driven by the crankshaft via a V-belt. Water cooled in the radiator is sucked into the water pump from its lower portion and is sent from the center of the water pump impeller (4) radially outward into the water jacket in the crankcase. (1) Bearing Unit @) Water Pump Body @) Mechanicel Seat (2) Water Pump Impeller 0109031 M9“Bémm STROKE SERIES WSM,02400 [3] THERMOSTAT 1.3 COOLING SYSTEM The thermostat maintains the cooling water at correct temperature. KUBOTA’s engine uses a wax pellet type thermostat. Wax is enclosed in the pellet. ‘The wax is solid at low temperatures, but tums liquid at high temperatures, expands and opens the valve. (A) At low temperatures (lower than 71°C (160°F)) As the thermostat is closed, cooling water circulates in the engine through the water return pipe without running to the radiator. Air in the water jacket escapes to the radiator side through leak hole (6) of the thermostat. (8) Athigh temperatures (higher than 71°C (160°F)) When the temperature of cooling water exceeds 71°C (160°F), wax in the pellet turns liquid and GOO conzro4s coa2roag (1) Seat (5) Synthetic Rubber @) valve (6) Leak Hole @) Pellet 7) Wax(solid) (2) Spindle (8) Waxiliquio) ‘expands. Because the spindle (4) is fixed, the peliet (3) is lowered, the vaive (2) is separated from the seat (1), and then cooling water is sent to the radiator. [4] RADIATOR (not included in the basic engine) oo7erota co0a2F0s0 The radiator core consists of water carrying tubes and fins (3) at a right angle to the tubes (2). Heat of hot water in the tubes is radiated from the tube walls. and fins. KUBOTA’s engine uses corrugated fin type core which has a light weight and high heat transfer rate. Clogging is minimized by the louverless corrugated fins (1) Cooling air Q) Tube 8) Fin {a} Louverlers Corrugated Fin 45) Louvered Corrugated Fin [5] RADIATOR CAP 001 14083 (8) The radiator cap is for sustaining the internal pressure of the cooling system at the specified level 88-kPa_(0.9 kgf/cm?, 13-psi}- when the engine is in operation. The cap consists of a pressure valve (1) a vacuum valve (2), valve springs, gasket, etc. Cooling water is pressurized by thermal expansion of steam, and as its boiling temperature rises, generation of air bubbles will be suppressed. (Air bubbles in cooling water lowers the cooling effect.) TA]. when radiator internal pressures high [6]. when radiator internal pressures negative (1) Presture Valve (2) Vacuum Valve 0011F034. M4 FUEL SYSTEM -@ FUEL SYSTEM [1] GENERAL ‘Gaim STROKE SERIES WSW 02400 *(0) Fuel Tank @) Fuel Filter @) Injection Pump {8} injection Pipe (8) Injection Nozzle (6) Fuel Overttow Pipe 7#{7) Fuel Feed Pump 0109F032 Fuel from the fuel tank (1) passes through the fuel filter (2), and then enters the injection pump (3) after impurities such as dirt, water, etc. are removed. The fuel pressurized by the injection pump to the opening pressure (13.73 to 14.71 MPa, 140 to 150 kgt/cm?, 1991 to 2062 psi), of the injection nozzle (5) isinjected into the combustion chamber. Part of the fuel fed to the injection nozzle (5) lubricates the moving parts of the plunger inside the nozzle, then returns to the fuel tank through the fuel ‘overflow pipe (6) from the upper part of the nozzle holder. mNOTE Component marked * is not included in the basic model. ‘© Component marked ** is included only in the basic model. [2] FUEL FILTER (not included in the basic model) 1096053 Each moving part of the injection pump and nozzle is extremely precision machined, and clearances of thelr sliding parts are extremely smatt- Fuel itself serves as lubricating oll. For this reason, it is extremely important to completely remove water and dirt contained in fuel. This fuel filter, which uses very fine filter paper, serves to separate and filter dirt in fuel and water accumulated in the tank. Air vent plug is fitted to the cock body. Before starting or after disassembling and reassembling, loosen this plug and bleed the air in the fuel system. 4A) Inlet (@) Outlet (1) Fuel Cock aie Vent Prag @) Fiter Element (@) FiterCup‘6emim STROKE SERIES WSW,02400 [3] FUEL FEED PUMP M.4 FUELSYSTEM The filtered fuel is fed to the injection pump by the fuel fed pump. The chamber (1) is enclosed with the inlet valve (2), the outlet valve (5) and the diaphragm (6), which is, linked to the rocker arm with the pull rod (7). The rocker arm is swinged by the eccentric cam on the fuel camshaft (4). ‘When the diaphgram is pulled down, vaccum in the chamber (1) causes the outlet valve (5) to ciose and the atomospheric pressure in the fuel tank to force the fuel into the chamber, opening the inlet valve (2). When the diaphragm is pushed up by the cam, the pressure in the chamber causes the inlet valve to close and forces out the fuel, opening the outlet, valve. (A) Inlet Stroke 18) Discharge Stroke (2) from fuel fier () toinjection pump (1) Chamber {5) Outlet Valve 2) Inlet valve {(6) Diaphragm @) Rocker Arm (7) PullRos (2) Fuel Camshaft ov09F023 [4] INJECTION PUMP ‘A Bosch MD type mini pump is used for the injection pump. tt is small, lightweight and easy to handle. The plunger _(7)-with a right-hand _tead-recipro- cates via the tappet roller (9) by means of the comshaft fuel cam, causing the fuel to be delivered into the injection nozzle. (1) Delivery Valve Holder (8) ylinder (@) Delivery Valve spring (7) Plunger @) Delivery Valve (@) Plunger spring (@) Control Rod (9) Teppet ©) Contiol sleeve 109034 M12- M4 FUEL SYSTEM (1) Pump Element Gemnmh STROKE SERIES WSMO2400 The pump element (1) is consist of the plunger (3) and cylinder (2). The sliding surfaces are super-precision machined to maintain injection pressure at engine low speeds, Since the driving face (7) fits in the control sleeve, the plunger (3) is rotated by the movement of the control rack to increase or decrease of fuel delivery. As described above, the plunger (3) is machined to have the slot (5) and the control groove (6). (1) Pump clement (5) sot 2) Gfinder {© Contrl Groove Era: @) Plunger (7) Driving Face {@) Feediole 01 083 (2) Delivery Valve =a The delivery valve consists of the valve (1) and the Valve seat (2). The delivery valve prevents the fuel from flowing back into the delivery chamber through the injection pipe. It also prevents the fuel from dribbling at the 90117042 if injection nozzle- When the delivery stroke ends the relief plunger moves into the bore of the valve seat and seals the delivery line from the delivery chamber. The relief plunger lowers further until the valve seats suck back the fuel to prevent dribbling at the injection nozzle. (1) Valve (2) Reliet Plunger (2) ValvesSeat (3) Dumping Valve 0087F025 1. At fuel injection Since dumping valve is pushed up to press the spring, fuel is pressure-fed to injection nozzle the same as without dumping valve. 2. At suck-back ‘At suck-back by delivery valve after fuel injection fuet returns through dumping valve orifice Generally second injection is apt to occur by reflex pressure due to reaction of sudden pressure drop when changing into suck-back by delivery valve from high injection pressure. As a result of preventing this second injection perfectly by dumping valve and dissolving nozzle clogging, durability of injection nozzle is improved.arorh STROKE SERIES WSU id FUEL SYSTEM (4) Operation of Pump Element 1. Before delivery As the tappet lowers, the plunger (2) also lowers and fuel is drawn into the delivery chamber (1) through the feed hole (5) from the fuel chamber ). 2. Beginning of delivery When the plunger is pushed up by the cam and the head of the plunger closes the feed hole, the pressure in the delivery chamber rises to push the telief plunger (3) open. Fuel is then force-fed into the injection pipe. Delivery While the plunger is rising, the delivery of fuel continues, 3 4. End of delivery When the plunger rises further and the control groove (6) on its periphery meets the feed hole,the fuel returns to the fuel chamber from the delivery ( chamber through the control groove and the feed hole. |.(1)-Doivery Chamber_—___(8) Fuel Chamber Ut U (2) Plunger (6) Feedtole G) elit Plunger 16) Contre! Groove 0011048 . (5) Injection Control 1. No fuel delivery At the engine stop position of the control rod (3), the lengthwise slot (1) on the plunger (2) aligns with the feed hole (5). And the delivery chamber (4) is led to the feed hole during the entire stroke of the plunger. ‘The pressure in the delivery chamber does not build up and no fuel can be forced to the injection nozzle. 2. Fuel dativery The plunger (2) is rotated (See figure) by the controt rod (3). When the plunger is pushed up, the hole (5) is closed. The pressure in the delivery chamber (4) builds up and forcefeeds the fuel to the injection nozzle until the control groove (6) meets the feed hole (5). The amount of the fuel corresponds to the distance "A" 1) Sot (@) Delivery chamber 12) Plunge (5) Feed Hole 8) Control Rod (6) Control Groove 0 109F304‘M4 FUEL SYSTEM, . [5] INJECTION NOZZLE This nozzle is throttle-type. The needle vaive (5) is pushed against the nozzle body (4) by the nozzle spring via the push rod (3). Fuel pressurized by the injection pump pushes the needle valve up and then is injected into the sub-combustion chamber. Excessive flow passes from nozzle holder center through the eye joint and the fuel overflow pipe to the fuel tank, The injection pressure is 13.73 to 14.71 MPa (140 to 150 kgf/em2, 1991 to 2133 psi), and is adjusted with adjusting washers (2). 1) Nozzle Holder Body (a) Nozzle Body @) Adjusting Washer 15) Needle Valve @) Push Rod atn6ro12: - [6] GOVERNOR The governor controls the amount of the fuel to be fed in the entire speed range to prevent the engine from changing its speed according to the loa The fork lever 1 (3) is held where two forces on it are balanced. One is the force that fork lever 2 pushes, which is caused by the tension of the governor spring (4) between the governor lever (1) and fork lever 2 (5). Another is the component of the centrifugal force produced by the steel balls (6) which are rotated by the fuel camshaft (10). WAtstert ‘The steel ball (6) has no centrifugal force. Fork lever 1 (3) is pulled by the start spring (2) and the control rod (13) moves to the maximum injection position for easy starting. mating When the speed control lever (12) is set at the ling position, the governor spring (4) 1 pulled slightly f ‘As the camshaft rotates, the steel ball (6) increase their centrifugal force and push the governor sleeve (7). Fork lever 1 (3) pushed by the governor sleeve, pushes the control rod (13) and the control rod compresses the idling adjust spring (11). 0 109F035, The control rod is kept at a position where the centrifugal force is balanced with the spring tensions {1) Governor tever (@) Steet Ball ‘on the control rod, providing stable idting. 9} Governor Bal (3) Forktevert (0) Fuel Camshaft {@) Governor Spring (11) idling Alust Spring (9) Fork Lever? (12) Speed Control Lever (6) Steel Bal 413) Control Rod () Governor sieeve Mas eas STROKE SERIES WSNLO2a0068mm STROKE SERIES WSM.02400 0109F038 HL At medium or high speed running When the speed control lever (1) is turned further, ‘the governor spring (2) increases the tension and the control rod (3) is pulled to increase the engine speed. The steel ball (4) increase their centrifugal force and the control rod is pushed, decreasing the engine speed, until the centrifugal force and the spring tension are balanced: When the engine speed is dropped (A~28) with the increase of the load (a~rb), the centrifugal force of the steel ball decreases and the control rod is pulled. The amount of the fuel to the injection nozzle is increased to produce a higher engine torque required for the load. (1) Speed Control Lever (2) Controt rod 2) Governor Spring (@) Steet eal At maximum speed running with an overload ‘When the engine is overloaded at the high speeds 01095039 ‘and the engine speed drops, the centrifugal force of ‘the steel ball (6) decreases and the governor spring (2) pulls fork lever 1 (1) and 2 (3). ‘When fork lever 2 contacts the adjusting screw (5), ‘the spring (4) which is built in fork lever 1 begins to push the fork lever 1 to pull the control rod. The fuel to the injection nozzle is increased to run the engine at high speed and torque. (1) Fork Lovert (2) Spring @) Governor Spring (5) Adjusting Screw. @) ForkLever2 (6) Steel Ball o109F040 To stop the engine When the stop lever (1) is moved to the stop position, fork lever 1 (2) is pushed and the control rod (3) is moved to stop the fuel injection. (1) StopLever ©) Control Rod {@) Fork Levert M6. MS ELECTRICALSYSTEM _Bamm STROKE SERIES WSM,02400 - fl ELECTRICAL SYSTEM za -Z482-B-D662-B-D722-B 1167013, The electrical system of the engine consists of a starting system (including a starter, glow plugs and others), a charging system (including an AC dynamo, a regulator and others), a battery and an oil switch. mNOTE © Components marked * are not included in the basic model. [1] STARTING SYSTEM (1) Starter oro9s003 (2) Olt Pressure Switch *(8) LampTimer @) GlowPlug *(9) Keyswitch (@) ACDynamo *(10) Charge Lamp (@) Regulator sO) Light (5) Battery #112) Solenoid (©) Starter #03) Timer *(7) OilLamp. The starter is of the electromagnetic drive type. It is composed of a starting motor and a solenoid switch. (1) Solenoid switeh (6) Commutator (@) Plunger (7) Armature @) Spring (@) Field Coit (2) Shift Lever (8) Overrunning Clutch (5) Brush M17,o109Fo88 1. Schematic Circuit (1) Key Switeh (@) Field Coit (2) Solenoid switeh (@) Commutator @) Holding coil (10) Brush (2) Pullin Cou (1) Armature (5) Plunger (12) Spiral Spline (©) Rod (13) Overeunning Clutch () Shift Lever (14) Pinion 2, Overrunning Clutch The overrunning clutch is so constructed that the power transmission relationship is automatically severed when the clutch pinion shaft (6) speed exceeds the clutch gear outer (1) speed at increased engine speeds, Therefore, the armature drives the ring gear and is never driven by the engine. IA] when poweris {8} ting rotation with cluteh tte ‘that of clutch gear outer tal 8 (1) Clutch Geor outer (8) Spline Tube inner (2) Roller 18) Pinion Gear 0007F088 (3) Roller Spring (6) Clutch Pinion Shaft oo7Foaa 3. Solenoid Switch The solenoid switch forces out the pinion for engaging with the ring gear, and operates as a relay to drive the armature It consists of a pull-in coil, @ holding coil and a plunger. (1) Plunger (@) Puttin coi (2) Spring (6) Holding Coit 8) Contact late+ M5 ELECTRICAL SYSTEM ‘68mm STROKE SERIES WSN,02400 o109F045 4. Operating of Starter Wl When Main Switch is Turned to “START” Position The contacts of main switch (1) close and the holding coil (3) is connected to the battery to pull the plunger (5). ‘The pull-in coil (4) and the starting motor are also connected to the battery. The pinion (8) is pushed against the ring gear (9) with the overrunning clutch (7) by the drive lever (6) and the solenoid switch (2) is closed. (1) Main switch (6) Drive Lever @) Solenoid Switch (7) Overrunning Clutch G) Holding Coil {8} Pinion (4) Pulkin Coit (8) Ring Gear (5) Plunger 0109F046 Wl When Solenoid Switch Is Closed The current from the battery flows through the solenoid switch (2) to the starting motor. The pinion (7), which is pushed against the ring gear (8) and rotated along the spline (5), meshes with | the ring gear to erank the engine. The engine starts and increases its speed. While the pinion spins faster than the armature, the overrunning clutch (6) allows the pinion to spin independently from the armature. The pull-in coil (3) is short-circuited through the solenoid switch (2) and the main switch (1) (2) Main Switch 15) Spiral spline @} Solencid Switch (©) Overruaning clutch 8} Pullin coil () Pinion (a) Armature (@) Ring Gear orosroa7 I When Main Switch Is Released The current from the battery flows to the holding coil_(1) through the pull-in coil (2) to diminish the ‘magnetism between them, ‘The plunger (3) is pushed by the spring to pull in the pinion, (1) Holding Coit @) Plunger (2) Puttin Coil M19sinm STROKE SERIES WSM.02400 — ~ (2) Glow Plug oon tF77 type. (1) Insulating Powder (2) Metal Tube (3) Key Switch (not included in the basic model) Each sub-combustion chamber has a glow plug for easy starting. The glow plug is of the quick-heating @) Housing (4) Heatcoi The key switch has 4 positions. The terminal “BAT” tae is connected to the battery. moss Sosa The key released at the “PREHEAT” position ARS returns to the “OFF” position. And it released at the “START" position returns to the “ON" position IM.5 ELECTRICALSYSTEM 01096307 I PREHEAT (1) Lamp Timer 2) ToGlow Plugs @) From Battery mi START the starter. (1 Tostarter @) 1oGlow Plug ) Fromsattery While the key switch is turned and held at the “PREHEAT” position, the current is supplied to the glow plugs through the lamp ti 6) To Accessory When the key is turned to the "START" position, through the "ON" position the current is supplied to (® ToRegulator (5) Tool Presuretamp ane accessory ‘o3saron7, M20. M5 ELECTRICAL SYSTEM — ~ ‘sai STROKE SERIES WSW,02400 at Osan MON Only the terminal “AC” is connected to the battery. At any position of the key except the “OFF” position, the terminal "AC" is connected to the "BAT" terminal. (1) From eattery @) ToOllPressure Lamp and 2) ToRegulator accessory 2] CHARGING SYSTEM (1) Dynamo: This dynamo is an 8-8 pole rotating magnet type generator. It is simple in construction, consisting of a stator and rotor. The rotor is made up of eight permanent magnet pole pieces assembled on a shaft and rotates on the center of the stator around which 03397516 eight electromagnetic coils are provided for. This dynamo produces higher voltage in slow speed rotation, and charges electric current to the battery during engine idling. (2) Regulator TA Seneatiing fag Bisgrammne oe cablogeatntral rmeines Sehaltsdhe 02035013 The regulator performs rectification and voltage regulation. The regulator converts AC into DC which flows through the power consuming circuits and the battery, and also charges the battery. If however, the battery voltage exceeds a certain level. The DC current is cut off from the charging circuit to prevent overcharging. (Gy Regulator (6) bloetead Wire Q) Dynamo 1) Yellow Lead Wire @) Load (®) Rediead Wire 1) charge Lamp (9) Green Lead Wire (5) Battery (10) slack Lead wire Meatémm STROKE SERIES WSM,02400_ (3) Charging Mechanism M.5_ELECTRICAL SYSTEM The charging mechanism is described in four sections: 1) When key switch is ON 2) Atstarting 3) Incharging 4) Over-charge protection (1) GEN: Magnet type AC generator (2) LAMP: Charge indication lamp (not included in the basic engine) (3) KEY SW: Key switch (not included in the basic engine) (4) BATT: Battery (not included jn the basic engine) (5) Blue: GEN connecting terminal (6) Red: BATT + connecting terminal (7) Yellow: BATT voltage test terminal (8) Black: BAT—connecting terminal (9) Green: LAMP connecting terminal $1.52: Output controlirectification thyristor (SCR) Dj, Dz: Output rectifying diode onrar0se D3, Da: GEN generation detecting diode Ds,Dg: Protection diode for wrong connecting of BATT 2): BATT terminal voltage setting diode Qi: GEN generation detecting transistor Qp: LAMP on/off transistor Qa: Gate current control transistor Qa: BATT voltage detecting transistor 1) When Key Switch is "ON" When the engine is at standstill with key switch set, at position 1, the circuit functions to light LAMP, as shown in Fig. 1. With key switch at position 1, current flows to base of Qo through the route of BATT ~ emitter/base of Qz ~~ Ri ~~ Dg ~—- BATT and collector of Q; is then turned on. As a result, current also flows to LAMP though the route of BATT ~ emitter/collector of Qz -— Ds --— LAMP ~-* BATT lighting LAMP to indicate that charging is not carried out. At this time, though current flows to base of Qs through the route of BATT —~ emitter/base of Q3 ~ — Ra ~~ Dg--—- BATT, collector of Q3 has no current because GEN is stationary. M22__Gamm STROKE SERIES WSM,02400— 0172F053 2) AtStarting When key switch is turned to position 2, coil of starter relay is energized and starter starts engine. GEN also starts generation for charging and LAMP is tumed off In detail, with GEN starting, current flows to base of Q; through the route of GEN —- Dj ~ emitter/base of Qi + Ry — Da > GEN, or GEN emitter/base of Qy ~~ Ra D3 therefore current also flows through Qu, short- circuiting emitter and base of Qo. As a result, base current of Qz is interrupted, Q2 is turned off and accordingly current to LAMP is also interrupted. 3) In Charging Because BATT terminal voltage just after engine start is lower than setting value (14 to 15V), of lower than zener lever of 2), current is not supplied to base of Qs and Qa is off, as shown in Fig. 2. Qs is on with base current which flows through the route of BATT - == emitter/base of Q3 -— Rp ~~ Dg -— BATT, and gate current is supplied to S; or S2 through the route o172F0s4 ‘of GEN = D; = emitter/collector of G3 — Rz — gate/cathode of S ~ GEN, or GEN => Dp emitter/collector of Q3 ~~ R3 ~~ gate/cathode of Sy -— GEN. When engine speed is increased so that GEN generation voltage becomes higher than BATT terminal voltage S; of S2 is turned on and, as shown in Fig. 3, charge current is supplied to BATT through the route of GEN — Dy ~ BATT ~ anode/cathode of, Sz — GEN, or GEN --~* Dy “> BATT --— anodeicathode of Sy -— GEN. After $; oF 5; is turned on, collector current of Qy and base current of Q3 are supplied by GEN, not BATT. When key switch is returned to position 1 after engine is started, BATT is charged, if BATT terminal voltage is lower than the setting value, or zener level, ofZy 4) Over-Charge Protection ‘When BATT terminal voltage is higher than the setting value or zener level of 2), BATT is not charged, by the function of circuit as shown in Fig, 4, That is, Qa is on with base current which flows through the route of BATT -——- emitter/base of Qa Z1 =~ Dg ~ = BATT, shorteircuiting emitter and base of Q3. Therefore, Q3 is off with no base current and gate current is not supplied to $; and Sz. Consequently Sy 0172F055 and Spare ot M23,8mm STROKE SERIES WSM,02400 GENERAL [1] ENGINE IDENTIFICATION Model Name and Engine Serial Number ‘When contacting the manufacturer, always specify your engine model name and serial number. diesel engine are designated as shown in the figure. ‘The sequence of cylinder numbers is given as No.1, No.2, No.3 starting from the gear case side An6F018 [2] GENERAL PRECAUTIONS lM Precation at overheating Take the following actions in the event the coolant temperature be nearly or more than the boiling point, what is called “Overheating”. (1) Stop the machine operation in a safe place and keep the engine unloaded idling, (2) Don't stop the engine suddenly, but stop it after about 5 minutes of unloaded idling. (3) Keep yourself well away from the machine for further 10 minutes or while the steam spout out. (4) Checking that there gets no danger such as burn, get rid of the causes of overheating according to the manual And then, start again the engine. S4+ S.G GENERAL “comm STROKE SERIES WSM,02400 © During disassembly, carefully arrange removed parts in a clean area to prevent confusion later. Screws, bolts and nuts should be replaced in their original position to prevent reassembly errors. © When special tools are required, use Kubote's genuine special tools. Special tools which are not frequently used should be made according to the drawings provided. © Before disassembling or servicing live wires, make sure to always disconnect the grounding cable from the battery first. ‘¢ Remove oil and dirt from parts before measuring # Use only Kubota genuine parts for parts tal e replacement to maintain engine performance and to ensure safety @- © Gaskets and O-rings must be replaced during reassembly. Apply grease to new O- seals before assembling. o- ‘© When reassembling external or internal snap tings, position them so that the sharp edge faces, By against the direction from which force is applied. Be sure to perform run-in the serviced or reassembled engine. Do not attempt to give heavy ® oad at once, or serious damage may result to the 19s oF oil A cvron © All current Kubota production engines are asbestos-free. However, some engines, which were produced bofore the introduction of applying asbestos-free regulations, are stil being used in the market, In servicing such as overhauling for the engine ‘which contain asbestos, follow the specified safety rules and regulations and handle them with due ca () Grease @) Force {G) Place the Sharp Edge against the Direction of Force 1A). External snap Ring 1B] Internal Snap Ring 82‘séimm STROKE SERIES WSW.02400 S.G GENERAL [3] TIGHTENING TORQUES Screws, bolts and nuts must be tightened to the specified torque using a torque wrench, Several screws, bolts and nuts such as those used on the cylinder head must be tightened in proper sequence and at the proper torque. (1) Tightening torques for special use screws, bolts and nuts Note © In removing and applying the bolts and nuts marked with “*", pneumatic wrench or similar pneumatic ‘tool, if employed, must be used with enough care not to get them seized. © For “*” marked screws, bolts and nuts on the table, apply engine oil to their threads and seats before tightening. Item Size xPitch Nem kgfm ftlbs * Head cover cap nuts M6x 1.0 3.91059 0.41006 2.91043 * Head bolts Max1.25 | 39.2to441 | 401045 28.910 32.5 * Bearing case bolts 1 6x 1.0 12.70 15.7 13t01.6 9.410 11.6 * Bearing case bolts 2 M7x1.0 26.5t0304 | 27t03.1 19,5 1022.4 * Flywheel bolts mi0x1.25 | 53910588 | 5.5t06.0 39.8 1043.4 * Connecting rod bolts M7x0.75 | 26510304 | 271031 19.5t022.4 * Rocker arm bracket nuts M6x1.0 | 9.81t011.28 | 1.00t01.15 | 7,23t08.32 * idle gear shaft bolts M6x1.0 | 9.814011.28 | 1.00t01.15 | 7.23t08.32 Glow plugs MBx 1.0 7.810 14.7 0.80 1.5 5.8t0 10.8 Nozzle holder assembly M20x15 | 49.0t0686 | 5.0t07.0 36.220 50.6 Oil switch taper screw Pre 14,7t0196 | 1.5t02.0 10.810 145 Injection pipe retaining nuts Mi2x15 | 245t0343 | 251035 18.1 1025.3 Starter'sterminal 8 mounting nut ue 8810118 0.9012 651087 (2) Tightening torques for general use screws, bolts and nuts. When the tightening torques are not specified, tighten the screws, bolts and nuts according to the table below. Grade ‘Standard Screw and Bolt Special Screw and Bolt oO ® @ Nominal oni Diameter Nem kgfm ftlbs Nem kgf-m ftlbs M6 7.9109.3 [0.80100.95| 5.81069 | 9.8t011.3 [1.0010 1.15 |7.23108.32 mes 17,710206| 1.8t02.1 [13.00 15.2 |235t0275| 241028 |17.4t0203 M10 B92t045.1[ AOt04G [28910333 | 48.11055.9| 49057 [35.4to41.2 m2 62810726] 6.4t07.4 [46.310535|775t0902| 7.91092 [57110665 Screw and bolt material grades are shown by numbers punched on the screw and bolt heads. Prior to tightening, be sure to check out the numbers as shown below. Punched Number Screw aid Bolt Material Grade None ora “Standard Screw and Bol S541, S200 7 ‘Special Screw and Bolt S43C, SABC (Refined) $3‘66mm STROKE SERIES WSM,02400 S.G GENERAL, . [4] TROUBLESHOOTING i Reference Symptom Probable Cause Solution rege Engine Does Not | © No fuel Replenish fuel = Start © Airin the fuel system Bleed air S14 # Water in the fuel system Replace fuel and repair - ‘or replace fuel system Fuel pipe clogged Clean - Fuel filterclogged Replace S16 © Excessively high viscosity of fuel or Use the specified fuel or | 5-15 engine oil at low temperature engine oil '* Fuel with low cetane number Use the specified fuel - @ Fuel leak due to loose injection pipe | Tighten nut S27 retaining nut 4 Incorrect injection timing Adjust S57 © Fuel cam shaft worn Replace = injection nozzle clogged Clean $56 injection pump defective Repair or replace 557 Fuel pump defective Repair or replace - © Seizure of crankshaft, camshaft, piston | Repair or replace - or bearing © Compression leak from cylinder Replace head gasket, | 5-24 tighten cylinder head bait, glow plug and holder # Improper valve seat alignment, valve | Repair or replace 539 spring broken, valve seized Improper valve timing ‘Adjust $57 Piston ring worn Replace 5:34 Excessive valve clearance Adjust 5-19 [starter Does Not Battery discharged Charge - Work} Starter detective Repair or replace 561 ‘Main switch defective Repair or replace - : © Wiring disconnected Connect = Engine Revolution Fuel filter clogged or dirty Replace $16 Is Not Smooth Aircleaner clogged Clean or replace 515 Fuel leak due to loose injection pipe | Tighten nut 4 retaining nut © Injection pump defective Repair or replace $37 © Incorrect nozzle opening pressure Adjust $56 6 Injection nozzle suck or clogged Repair or replace 5-56 @ Fuel over flow pipe clogget Clean - # Governor defective Repair - Either White Or © Excessive engine oil Reduce to the specified - Blue Exhaust Gas Is level Observed ‘© Piston ring worn oF stuck Replace 534 # Incorrect injection timing Adjust 557 © Deficient compression Check the compression | $-24 pressure Either Black Or ‘* Overload Lessen the load - Dark Gray Exhaust Low grade fuel used Use the specified fuel - Gas Is Observed Fuel filter clogged Replace S16 # Aircleaner clogged Clean or replace 515 © Incorrect injection timing Adjust S57 # Engine’s moving parts seem to be Repair or replace - seizing * Uneven fuel injection Repair or replace the - . injection pump © Deficient ect repl 6 nozzle © Compression leak Replace head gasket, | $-24 tighten cylinder head > bolt, glow plug and nozzle holder S-4Gemm STROKE SERIES WSM,02400 S.G GENERAL S5 Symptom Probable Cause Solution Excessive © Oil ring worn or stuck Replace Lubricant Oil © Piston ring groove worn Replace the piston Consumption © Valve stem and guide worn Replace © Crankshaft bearing, and crank pin Replace bearing worn Fuel Mixed into Injection pump’s plunger worn Replace pumpelement | — Lubricant Oil ‘or pump Water Mixedinto | © Head gasket defective Replace 5-28 Lubricant Oil # Crank case or cylinder head flawed Replace $37 LowOilPressure | ¢ Replenish - © Oil strainer clogged Clean $32 © Oil filter cartridge clogged Replace 546 © Relief valve stuck with dirt Clean - © Relief valve spring weaken or broken | Replace - © Excessive oil clearance of crankshait Replace S-48, 49, bearing 50 © Excess a ker ar pI tt boss. © Oil passage clogged Clean - © Different type of oil Use the specified type | 5-15 of oil © Oil pump detective Repair or replace $52, 53 High Oil Pressure | © Different type of oil Use the specified type | 5-15 of oil © Relief valve defective Replace - Engine © Engine oil insufficient Replenish - Overheated © Fan belt broken or tensioned Replace or adjust S45 improperly © Coolant insufficient Replenish - © Radiator net and radiator fin clogged | Clean - with dust © Inside of radiator corroded Clean or replace Si7 © Coolant flow route corroded Clean or replace S17 t '& Radiator cap detective Replace S54 © Radiator hose damaged Replace S16 ‘© Thermostat defective Replace S55 ‘© Water pump defective Replace 5-55 * Overload running Loosen the load - Battery Quickly | © Battery electrolyte insufficient Replenish distilled - Discharge water and charge © Fan belt sips Adjust belt tension or | $-54 replace © Wiring disconnected Connect - @ Regulator defective Replace - # AC dynamo defective Replace $60 © Battery defective Replace =. SG GENERAL [5] SERVICING SPECIFICATIONS (1) ENGINE BODY Cylinder Head __Gamm STROKE SERIES WSM,02400 Item Factory Specification Allowable Limit Cylinder Head Surface Flatness Top Clearance 0.50 to 0.70 mm, 0.0197 to 0.0276 in. Cylinder Head Gasket Thickness Free 1.15 to 1.30 mm = (Grommet Section) 0.04153 to 0.0512 in. Tightened 1.05 to 1.15 mm 1 0.0413 to 0.0453 in. ‘Compression Pressure 2.8410 3.24MPa 2.26 MPa 29t0 33 kat/cm? 23 kgffem? 412 to 469 psi 327 psi Valves alve Clearance {€ 145 100.485 my 0.0057 to 0.0073 in, Valve Seat Width 212mm - 0.0835 in, 7 Valve Seat Angle 0.785 rad. - 45° Valve Face Angle 0.785 rad. = 45° Valve Recessing -0.10t0 0.10 mm 0.30 mm -0.0039 to 0.0039in. 0.0118in. Clearance between Valve Stem and Valve Guide (0.030 to 0.057 mm 0.1mm 0.00118 to 0.00224 in, 0.0039 in. Valve Stem 0.D. 5.968 to 5.980 mm_ 0.23496 to 0.23543 in, Valve Guide {.D. 6.010 to 6.025 mm 9.23661 t0-0.23720in, Valve Timing Inlet Valve ‘Open 0.35 rad. (209) = before T.D.C. Close 0.79 rad. (45*) i afterB.D.C. Exhaust Valve ‘Open 0.87 rad. (50°) - before B.0.C. Close 0.26 rad. (1 - after T.D.C. 866tinm STROKE SERIES WSW,02400 5.6 GENERAL Valve Spring Tem Factory Specification Allowable Limit Free Length 31.6mm 28.4 mm 1.244 in. 4.118in. Setting Load/Setting Length 64.7 N/27 mm 54.9 N/27 mm 6.6 kgf/27 mm 5.6kgi/27 mm 14.6 |bs/1.063 in. 12.3 Ibs/1.063 in. Tilt 1.2mm 0.047 in. Rocker Arm Clearance between Rocker Arm Shaft and shaft 0.016 to 0.045 mm 0.15 mm Hole 0.00063 to 0.00177 in. 0.0059 in. Rocker Arm Shaft 0.0. 10.473 to 10.484 mm 0.41232 to 0.41276 in. Rocker Arm Shaft Hole LD. 10.500 to 10.518 mm 0.41339 to 0.41410 in. ‘appet Clearance between Tappet and Guide 0.016 to 0.052 mm. 0.00063 10 0.00205 in. 010mm Tappet 0.0. 17.966 to 17.984 mm 0.70732 to 0.70803 in. Tappet Guide LD. 18.000 to 18.018 mm 0.70866 to 0.70937 in. Camshaft journal 0.0. Camstaft bearing |.D. Camshaft Camshaft Side Clearance 0.15t00.31mm o5mm 0.0059 to 0.01220in. 0.020in. Camshaft alignment = 0.01 mm 0.0004 in, Cam height (IN., EX.) 26.88 mm 26.83 mm 1.0583in. 1.0563 in. Oil clearance of camshaft 0.050 to 0.091 mm, 0.15 mm 0.0020 to 0.0036 in. 0.0059 in, 32.934 to 32.950 mm 1.2966 to 1.2972 in. 33,000 to 33.025 mm 1,292 to 1.3002 in S7» $.G GENERAL _ Timing Gear ‘samm STROKE SERIES WSN,02400 Item Factory Specification Allowable Limit Timing gear backlash Crank gear — Oil Pump Drive Gear 0.041 t0 0.123 mm 0.15 mm. 0.00161 to 0.00484 in. 0.0059 in. Idle gear - Cam gear 0.047 to 0.123 mm 0.15mm 0.00185 to 0.00484 in, 6.0059 in. Idle gear ~ Injection pump gear 0.046 to 0.124 mm 0.15mm 0.00181 to 0.00488 in. 0.0059 in. Idel gear - Crank gear 0.043 to 0.124mm 0.15 mm 0.00169 to 0.00488 in. 0.0059 in. Tle gear Side clearance 0.20t00.51 mm 0.60 mm 0.0079 to 0.0201 in. 0.0236 in. ‘Clearance between idle gear shaft and idle gear 0.020 to 0.084 mm 0.10 mm bushing 0.00079 to 0.00331 in, 0.0039 in. Idle Gear shaft 0.D. 19.967 to 19.980 mm - 0.78610 to 0.78661 in. __| ___Idle Gear Bushing |.D.. 20.000 to 20.051 mm = 0.78740 to 0.78941 in. Cylinder Liner +H (cteaineeranerpe 2442-512) | 64.0000 64.019 mm 64.169 mm eorcen 0662-B(E) | 2.51968 to 2.52043in. 2.52634 in, - 2482-B (E) 67.000 to 67.019 mm 67.169 mm D722-B {E) 2.63779 to 2.63854 in. 2.64444 in. O finder liner LD. 442-8 (E) 64.250 10 64.269 mm 64.419 mm eee 0662-8() | 2.52953 to 2.53028 in. 2.53618in, 7482-8 (E) 67.250 to 67.269 mm 67.419 mm 722-6 (€) 2.64764 to 2.64839 in. 2.65429 in. Crankshaft Cranksha‘t alignment - 0.02 mm. 0.0031 in. Oil clearance between crankshaft and 0.034 100.106 mm 0.20 mmr crankshaft bearing 1 0.00134 to 0.00417 in. 0.0079 in. Crankshaft 0.0. 39.934 to 39.950 mm - 1.57221 to 1.57284 in, Crankshaft bearing 1 LD. 39,984 to 40.040 mm - 1.57418 to 1.57638 in. Oil clearance between crankshaft and 0.034 to 0,092 mm 0.20mm crankshaft bearing 2 0.00134 to 0.00362 in. 0.0079 in. Crankshaft 0.D. 43,934 to 43,950 mm Z 1.72969 to 1.73032 in. rankshaft bearing 3.984. 6 1.73166 to 1.73331 in. S3881m STROKE SERIES WSY.02400 5.6 GENERAL Crankshaft Tem Factory Spec ‘Allowable Limit Oil clearance between crankshaft and 0.034 100.092 mm 020mm crankshaft bearing 3 0.00134 to 0.00362 in. 0.0079 in. Crankshaft O.D. 39.934 to 39.950 mm - 157221 t01.57284in, Crankshaft bearing 3 |.D. 39.984 to 40.026 mm - 1.57418 to 1.57583 in, Oil clearance between crank pin and crank pin 0.019 to 0.081 mm 015mm bearing 0.00075 to 0.00319 in. 0.0059 in. Crankshaft O.D. 33.959 to 33.975 mm - ; 1.33697 to 1.33759 n, a Crank pin bearing |.D. 33,994 to 34.040 mm 1.33835 to 1.34016in, Crankshaft side clearance 0.15 to0.31mm 0.5mm 0.0059 to 0.0122 in. 0.0197 in. ConnectingRod Connecting rod alignment = 0.05 mm 0.0020 in Clearance between piston pin and small end 0.014100.038 mm 010mm bushing 0.00055 to 0.00150 in. 0.0039 in. Piston pin 0.0. 20,002 to 20.011 mm 7 0.78748 to 0.78783 in. ‘Small end bushing I.D. 20.025 to 20.040 mm - 0.78839 to 0.78897 in Piston/Piston Ring ton pin hole |.D. 20,000 to 20.013 mm 20.05 mm 0.78740 to 0.78791 in. 0.7894 in Second compression 0.085 to 0.115 mm 0.15mm ring 2 0.0033 to 0.0045 in. 0.0059 in. Piston ring clearance Oil ring 0.02 to 0.06 mm 0.15mm 0.0008 to 0.0024 in. 0.0059 in. Top compression ring 0.15 10 0.30mm 1.2mm and oil ring 0.0059 to 0.01 18in. 0.0472 in. ca 0.30%00.45 1.2mm 00.45 mm Second compression ring 0.0118 to 0.0177 in. 0.0472 in. Oversize of piston rings +0.25mm os + 0.0098 in.S.G GENERAL 6mm STROKE SERIES WS¥,02400 + (2) LUBRICATING SYSTEM Oil Pump tem Factory Specification | Allowable Limit Engine oll pressure Atidle 98 KPa = speed 1.0kgf/em?2, 14 psi Atrated 196 to 441 kPa 98kPa speed 2.0t04.5 kgf/cm? 1.0 kgfiem? 28 to 64 psi 14 psi Clearance between inner rotor and outer rotor 0.03 to 0.14mm - 0.012 to 0.0055 in. Clearance between outer rotor and pump body 0.07 to 0.15 mm - 0.0028 to 0.0059in. End clearance between inner rotor and cover 0.075 to 0.135 mm - 0.0029 to 0.0053 in. (3) COOLING SYSTEM Thermostat ‘Thermostat’s valve opening temperature 69.5 10 72.5°C 7 157.1 to 162.5°F Temperature at which thermostat completely 85°C 7 opens: 185°F Radiator t Water tightness at ier cert specified pressure . Radiator water tightness Aeris 4.6 kgficm?, 23 psi TO seconds or more 7 88-59 kPa Radiator cap air leakage See an - 13-99 psi ; ‘Approx. 10 mm/98N e Fanbelttension 0.39;n./10 kof (22.1 Ibs.) (4) FUEL SYSTEM Injection Pump at 0.35 to 0.38 rad. before Injection timing ee eee ; ao 14.71 MPa Fuel tightness of pumpe element 150 kgfiem?, 2133 pa S seconds 1 i 14.7 > 13.7 MPa . Fuel tightness of delivery valve - tse 140 kgtfem? 2133 ~» 1990 psi