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Kubota L245DT, L2350, L2550 - Engine Service and Maintenance

Kubota L235, L245DT, L2350 tractors fitted with D1102 diesel engine. D1402 engine used in L2550 model.

Kubota L2350, L245DT, L2550, L235 - Diesel Fuel System

Kubota L235, L245DT, L2350, L2550 tractors are equipped with an inline, multiple plunger type injection pump, pintle nozzles and glow plugs. Because of extremely close tolerances and precise requirements of all diesel components, it is of utmost importance that clean fuel and careful maintenance be practiced at all times. Unless necessary special tools are available, service on injectors and injection pump should be limited of removal, installation and exchange of complete assemblies. It is impossible to re-calibrate an injection pump or reset an injector without proper specifications, equipment and training.

Fuel filter

On Kubota D1102, D1402 engines, filter life depends more on careful fuel system maintenance than it does on hours or conditions of operation. Necessity for careful filling with clean fuel cannot be over-stressed. Fuel filter should be renewed after every 400 hours of operation or once a year, whichever occurs first. Renew filter immediately if water contamination is discovered or a decrease in engine power is evident. Air must be bled from system after installing new filter. To bleed air from fuel system, open fuel shut-off valve and loosen air vent plug on filter base. When steady stream of fuel appears at vent plug, tighten plug. Loosen vent plug on fuel injection pump until air-free fuel appears, then tighten vent plug. If engine fails to start after bleeding air from filter and pump, loosen high pressure line connections at injector nozzles. Move throttle to run position and crank engine with starting motor until fuel appears at loosened injector line fittings. Tighten fittings and start engine.

Injection pump

Bosch K type pump is used on all models. The injection pump is a completely sealed unit and no service work or disassembly other than that specified should be attempted without necessary special equipment and training. Timing to engine - On Kubota D1102, D1402 engines, start of injection should occur at 25° BTDC. To check timing, disconnect fuel pressure line from injection pump front delivery valve holder. Place throttle control in maximum fuel position and pull decompressor knob out. Turn crankshaft slowly until wetness appears at discharge fitting of injection pump. At this point (beginning of injection), "F1" mark on flywheel should be aligned with timing check window. If timing requires adjustment, remove shims between injection pump mounting flange and cylinder block to advance timing or add shims to retard timing. Adding or removing one shim will change timing about 1,5 crankshaft degrees which is about 2.3 mm (3/32 inch) measured on flywheel rim.

Injection pump - Remove and reinstall

To remove injection pump, first thoroughly clean outside of pump and surrounding area. Shut off fuel and disconnect fuel supply line at injection pump. Remove high pressure lines leading to injectors. Remove side access cover or engine stop lever assembly if so equipped. Remove pump mounting stud nuts, align control rack pin with slot in crankcase and lift pump assembly from crankcase. Do not lose or damage shim pack located between pump flange and crankcase. Shims control pump timing and same number of shims must be reinstalled unless timing is to be changed. When reinstalling pump, be sure to guide rack control pin into notch in governor arm and crankcase. Use removed shim pack unless timing is to be changed. Bleed air from system as previously outlined.

Governor and fuel camshaft

Governor linkage adjustment - High speed adjustment screw and maximum fuel limit stop should not normally require adjustment unless governor or injection pump is overhauled. Adjustments should be made by qualified personnel only. Recommended slow idle speed is 800 to 850 rpm for all models. Adjustment is made by turning slow idle stop. High idle speed should be 2750 rpm for L235, L245DT, L2350 and 2950 rpm for L2550. Turn high idle stop screw for adjustment. Governor assembly can be removed with the drive gear and fuel camshaft as a unit after removing injection pump, fuel feed pump (if so equipped), timing gear cover and hydraulic pump and drive gear from rear end of fuel camshaft. Remove governor mounting cap screws and withdraw governor and camshaft as an assembly. To disassemble, remove fork pivot shaft and separate fork levers and fork lever holder. Remove drive gear retaining ring, then remove gear and weight assembly using a suitable puller. Governor weight thrust bearing contains 39 loose balls. Be careful that none are lost when weight unit is disassembled. Examine cupped race, balls and ball travel surface on back of gear for furrowing or pitting and renew if damaged. Inspect fuel camshaft and bearings for scoring, wear or other damage and renew as necessary. Reassemble by reversing the disassembly procedure. Be sure hydraulic pump drive gear is installed with hub facing forward. Bleed air from system, check timing and adjust governor linkage as previously outlined.

Injector nozzle

Testing and locating faulty nozzle - If engine does not run properly and a faulty injection nozzle is suspected, check for faulty nozzle as follows: With engine running at slow idle speed, loosen injector line at each nozzle in turn to allow fuel to escape at union rather than enter the cylinder. As in checking spark plugs in a spark ignition engine, the faulty nozzle is the one that least affects engine operation when its fuel line is loosened. Remove and test suspected nozzle (or install a new or reconditioned unit). A complete job of testing and adjusting injector requires use of special test equipment. Only clean, approved testing oil should be used in tester tank. Nozzle should be tested for opening pressure, nozzle leakage and spray pattern. Before conducting test, operate tester lever until fuel flows, then attach injector. Close valve to tester gage and pump tester lever a few quick strokes to clear air from tester and to be sure nozzle valve is not stuck. Nozzle should open with a buzzing sound and cut off quickly at end of injection.

Open valve to tester gage and operate tester lever slowly while observing gage reading. Opening pressure should be 13730-14700 kPa (1990-2135 psi) for all models. Opening pressure is adjusted by changing thickness of shim. A change in shim thickness of 0.1 mm (0.004 inch) will change opening pressure approximately 965 kPa (140 psi). To check for leakage, actuate tester lever slowly to maintain a pressure 1000 kPa (150 psi) below opening pressure. There should be no accumulation of fuel at nozzle tip. A slight wetting is allowed after 10 seconds if no drops are formed. If fuel leakage is evident, injector must be disassembled, cleaned and overhauled. Spray pattern should be well atomized and uniform emerging in a straight axis front nozzle tip. If pattern is wet, ragged or intermittent, nozzle must be overhauled or renewed.

Injector nozzle - Remove and overhaul

Before removing an injector, throughly clean injector, lines and surrounding area. Remove high pressure fuel line and disconnect bleed line. Unscrew nozzle holder from its mounting position on cylinder head. When reinstalling injector, make sure seating surface in cylinder head is completely clean and free from carbon buildup. Use a new seal washer underneath nozzle holder and tighten to 30-49 Nm (22-36 ft.-lbs.) torque. Hard or sharp tools, emery cloth, wire brush or grinding compound must never be used. An approved nozzle cleaning kit is available through a number of specialized sources. Wipe all dirt and loose carbon from exterior of nozzle assembly. Secure nozzle in a soft-jawed vise or holding fixture and remove nozzle nut. Carefully separate parts and place in clean calibrating oil or diesel fuel as they are removed. Be sure parts from each injector are kept together and separate from other units.

Clean exterior surfaces with a brass wire brush, soaking in an approved carbon solvent, if necessary, to loosen hard carbon deposits. Rinse parts in clean diesel fuel immediately after cleaning to neutralize the solvent and prevent etching of polished surfaces. Clean nozzle spray hole from inside using a pointed hardwood stick. Scrape carbon from pressure chamber using hooked scraper. Clean valve seat using brass scraper. Reclean all parts by rinsing in clean diesel fuel. Check nozzle fit by holding nozzle body vertically and lifting needle valve up about 1/3 of its length, then release needle. Needle must slide to its seat by its own weight. If needle movement is rough or sticky, reclean or renew nozzle valve assembly as necessary. Reassemble injector while parts are immersed in diesel fuel to avoid contamination. Make sure pressure adjusting shim is in place. Tighten nozzle nut to a torque of 59-78 Nm (44-58 ft.-lbs.). Do not overtighten as distortion may cause nozzle valve to stick and no amount of overtightening can stop a leak caused by scratches or dirt. Retest injector as previously outlined.

Glow plug

One glow plug is provided in precombustion chamber of each cylinder. To check glow plugs, disconnect wiring cable from glow plug terminal, then connect an ohmmeter across glow plug terminal and body. Resistance should be approximately 1.5 ohms. If resistance is zero ohms, glow plug is shorted. If resistance is infinite, an open circuit exists in glow plug.

Kubota L2350, L245DT, L2550, L235 - Cooling System

Kubota L235, L245DT, L2350, L2550 use a pressurized cooling system which raises coolant boiling point. All models use an impeller type centrifugal pump to provide forced coolant circulation and a thermostat to stabilize operating temperature. On tractors so equipped, the bypass type thermostat is located in coolant outlet elbow. Thermostat should begin to open at about 82C (180F) and be fully open at 95C (203F).

Radiator

Radiator cap pressure valve is set to open at 88.3 kPa (12.8 psi) on all models. Some tractors are equipped with a whistle-type warning device attached to radiator overflow pipe. Make sure whistle is operative and properly connected to radiator. To remove radiator, first drain coolant and remove hood. Disconnect radiator hoses and air cleaner hose. Remove mounting cap screws, then lift radiator from tractor.

Water pump

To remove pump, drain cooling system and remove radiator, if necessary, for access to pump. Remove fan belt, then unbolt and remove water pump. To disassemble pump, remove fan pulley using a suitable puller. Unseat pump shaft bearing front retaining ring, then press shaft and bearings forward out of impeller and pump body. Remove seal assembly from pump body. All water pump parts are available individually. To reassemble pump, reverse the disassembly procedure. On pumps equipped with fan pulley retaining nut, tighten nut to a torque of 70-78 Nm (50-58 ft.-lbs.).

Fan shaft

To remove cooling fan and shaft assembly, drain cooling system and remove radiator. Remove fan belt and fan. Remove retaining nut and withdraw fan shaft, pulley and bearings. Renew parts as needed. Reinstall fan shaft assembly by reversing removal procedure.

Kubota L2350, L245DT, L2550, L235 - Engine Components

Cylinder head

To remove cylinder head, first drain cooling system and disconnect battery cables. Remove hood, muffler and side covers (if equipped). Remove upper radiator hose, coolant return hose and intake manifold hose. Disconnect decompressor control cable. Remove injection lines and nozzle assemblies and cap all exposed fittings to prevent entry of dirt. Remove alternator adjusting bracket. Remove valve lever cover. Remove valve levers and shaft assembly and withdraw push rods. Remove cap screws and nuts securing cylinder head and lift head off cylinder block. One or more shims may he installed between gasket and cylinder head to adjust clearance between cylinder head and piston tops. Identify shims when cylinder head is removed, then install an equal number of shims when head is reinstalled. To check piston to head clearance, insert a soft lead wire through injection nozzle holder hole. Rotate crankshaft by hand until lead wire is flattened by piston top. Measure thickness of flattened wire to determine top clearance which should be 0.7-0.9 mm (0.028-0.035 inch).

Because of minimum amount of clearance that exists between valves and piston tops, loosen valve lever adjusting screws before reinstalling valve levers and shaft assembly to prevent possible damage to valves. Check cylinder head surface for distortion using a straightedge and feeler gage. If a 0.05 mm (0.002 inch) feeler gage can be inserted between cylinder head and straightedge, head surface should be refaced with a surface grinder. A maximum of 0.5 mm (0.020 inch) of material may be removed to true cylinder head surface. When installing cylinder head, use new head gasket and install shims (if used) between gasket and cylinder head. Be sure sealing surfaces are clean and dry. Apply light coat of engine oil to threads of retaining nuts and cap screws. Tightening torque is 73.5-78.4 Nm (55-58 ft.-lbs.). Adjust valve clearance and compression release mechanism. Retorque cylinder head cap screws and nuts after running engine for approximately 30 minutes using proper tightening sequence.

Compression release

Compression release mechanism is contained within valve lever cover. When decompressor knob is pulled, decompressor shaft rotates allowing adjusting screws to contact exhaust valve levers. The decompressor screws will hold exhaust valves slightly open, reducing compression resistance when starting engine, until decompressor knob is returned to normal operating position. To adjust compression release, remove adjusting covers from valve lever cover. Pull decompressor knob out, then turn crankshaft by hand until exhaust valve being adjusted is completely closed (piston at TDC compression stroke). Turn decompressor screw down until it contacts valve lever, then turn screw down an additional 1 to 1,5 turns to obtain specified valve opening of 0.750-1.125 mm (0.030-0.044 inch). Tighten locknut while holding adjusting screw. Repeat adjustment procedure for remainder of exhaust valves. After adjustment is completed, pull knob out and turn crankshaft by hand to make certain valves do not contact piston tops.

Kubota L2350, L245DT, L2550, L235 - Valves and Seat

Intake and exhaust valves are not interchangeable. All valves seat directly in cylinder head. Valve face and seat angles are 45 degrees for all valves. Recommended valve seat width is 2.1 mm (0.080 inch). Valve stem diameter is 7.960-7.975 mm (0.3134-0.3140 inches) for all valves. Face of valves should be recessed 1.1-1.3 mm (0.043-0.051 inch) below surface of cylinder head. Maximum allowable recession is 1.6 mm (0.063 inch). Whenever valves are renewed or reseated, be sure to adjust compression release mechanism as previously outlined. Valve clearance, gap between valve stem end and valve lever, is adjusted with engine cold. Recommended gap is 0.18-0.22 mm (0.007-0.009 inch) for both intake and exhaust. Due to close clearance between valves a pistons, severe damage can result from inserting feeler gage between valve stem and valve lever with engine running. Do not attempt to adjust valve clearance with engine running. To adjust valve clearance, proceed as follows: Loosen valve lever adjusting screw locknuts. Rotate crankshaft by hand to position number one piston at top dead center of compression stroke. Using a feeler gage to measure clearance, adjust valves for number one cylinder. Adjust remaining valves in sequence of firing order after positioning each piston at top dead center of compression stroke.

Valve Guides

Intake and exhaust valve guides are semi-finished and must be reamed after installation in cylinder head. Intake and exhaust valve guides are not interchangeable as exhaust guide is equipped with a carbon scraper at lower end of guide. Press new guides into cylinder head until guide shoulder is seated against surface of head. Kubota D1102, D1402 diesel engines are equipped with cup type stem seals which fit over stem end of valve guide. Desired operating clearance of valve stem in guide is 0.04-0.07 mm (0.0016-0.0028 inch). Maximum allowable clearance is 0.10 mm (0.0039 inch). Recommended finished inside diameter of valve guides is 8.015-8.030 mm (0.3156-0.3161 inch).

Valve springs and Valve levers

Valve springs are interchangeable for intake and exhaust valves. Approximate free length is 42 mm (1.65 inches) and minimum allowable free length is 41.2 mm (1.62 inches) on all models. Renew springs which are distorted, heat discolored or fail to meet following test specifications: Springs should test 117.7 N (26.5 pounds) when compressed to a length of 35.15 mm (1.384 inches). Minimum test specifications are 100 N (22.5 pounds) at 35.15 mm (1.384 inches). Intake and exhaust valve levers (rocker arms) are interchangeable on all models. However, it is recommended that valve levers be reinstalled in their original positions if not being renewed. All valve levers are equipped with renewable bushings. When installing new bushing, be sure hole in bushing is aligned with corresponding hole in valve lever. Recommended operating clearance of shaft in valve levers is 0.02-0.07 mm (0.0008-0.0028 inch) and allowable limit is 0.15 mm (0.006 inch). Shaft diameter should be 13.973-13.984 mm (0.5501-0.5506 inch) and bushing inside diameter should be 14.002-14.043 mm (0.5513-0.5529 inch). Valve levers and shaft are lubricated by oil metered to shaft support bracket from rear camshaft bearing. When assembling valve lever assembly, make sure all oil passages are open and properly positioned.

Cam followers and valve timing

Kubota D1102, D1402 engines are equipped with barrel type cam followers (tappets) which can be removed from the top after removing cylinder head. Cam followers operate directly in unbushed crankcase bores on all models. Check for wear or other damage and renew if necessary. Check camshaft at same time and renew if cam lobe surface is chipped, scored or excessively worn. Valve timing - Valve timing is correct when timing marks on timing gear train are aligned. Timing gear cover must he removed to check timing marks.

Timing gear cover

To remove timing gear cover, first separate front axle assembly from engine as follows: Drain cooling system. Remove hood, muffler, side covers and side rails (if equipped). Disconnect battery cables and remove battery. Disconnect upper and lower radiator hoses and intake manifold hose. Disconnect steering drag link from front axle. On tractors equipped with booster-type power steering, disconnect booster cylinder from front support. On tractors with front-wheel drive, remove drive shaft. On all models, support tractor underneath clutch housing and front axle. Remove fasteners securing front axle support to engine block, then roll front axle assembly and radiator as a unit away from engine. Remove injection pump side cover, then disconnect governor spring from governor lever. Remove speed control plate, then disconnect start spring from gear cover. Remove fan belt, then use a suitable puller to remove crankshaft pulley. Remove alternator and mounting bracket. Remove hour meter drive (if equipped) from front cover. Disconnect water pump by-pass hose. Remove retaining cap screws and withdraw timing gear cover. Crankshaft front oil seal can be renewed at this time. Seal should be installed with lip to the rear and front edge flush with front of cover bore. Apply grease to oil seal lip prior to reinstalling front cover. When reinstalling timing gear cover, be sure all O-rings are in position and water inlet nipple in cylinder block is free of rust, burrs or other imperfections which might damage O-ring. Be sure hour meter drive tang engages slot in end of fuel camshaft. Complete reassembly by reversing disassembly procedure.

Timing gear

Normal backlash between any two gears in timing train is 0.042-0.115 mm (0.0017-0.0045 inch) with a maximum allowable limit of 0.3 mm (0.012 inch). Crankshaft gear is light press fit on shaft and can be removed using a suitable puller. On Kubota L2550, a separate oil pump drive gear, installed in front of crankshaft gear, is also a light press fit. To install new gear, heat first to a temperature of 80-95C (175-200F) and install immediately. Make sure timing mark faces forward. Camshaft gear is a light press fit on shaft. Gear and shaft should be removed from cylinder block as a unit, then press shaft out of gear. Injection pump gear is a light press fit on fuel camshaft and is retained by a snap ring. Idler gear is equipped with renewable bushings. When reassembling timing gears, align timing marks.

Kubota L2350, L245DT, L2550, L235 Engine - Camshaft

To remove camshaft, first remove timing gear cover. Remove cylinder head and lift out cam followers. Remove two cap screws retaining camshaft thrust plate, then withdraw camshaft and drive gear as a unit. Be careful not to damage camshaft or bearing bores. Gear can be removed using a suitable press. Thrust plate controls camshaft or bearing bores. Gear can be removed using a suitable press. Thrust plate controls camshaft end play. Camshaft bearing journal diameter should be 39.934-39.950 mm (1.5722-1.5728 inches). Camshaft operates in unbushed bores in cylinder block. Bearing bore inside diameter should be 40.000-40.025 mm (1.5748-1.5758 inches). Desired operating clearance is 0.050-0.091 mm (0.0020-0.0036 inch) with a maximum limit of 0.15 mm (0.006 inch). Measured cam height should be 33.36 mm (1.313 inches) and minimum allowable height is 33.31 mm (1.311 inches). When reinstalling camshaft, thoroughly lubricate cams and bearing journals.

Rod and piston units

Connecting rod and piston units may be removed from above after removing cylinder head and oil pan. Be sure to remove ring ridge (if present) from top of cylinder before attempting to push piston out. Be sure to identify piston, rod and cylinder from which they came so units can be reassembled in original positions. Before removing piston from rod, mark top of piston in relation to alignment marks on connecting rod and identify piston and connecting rod as a pair to ensure correct assembly. When reinstalling piston and rod units, be sure connecting rod match marks are aligned and facing toward injection pump side of engine. Apply engine oil to connecting rod cap screws and tighten to a torque of 37-41 Nm (27-30 ft.-lbs.).

Pistons and rings

Three-ring, cam ground aluminum pistons are used on all models. Pistons and rings are available in standard size and 0.5 mm (0.020 inch) oversize. Piston ring end gap should be 0.30-0.45 mm (0.012-0.018 inch) for compression rings and 0.25-0.40 mm (0.010-0.016 inch) for oil control ring. Maximum allowable end gap for any ring is 1.25 mm (0.049 inch). Top compression ring is half-keystone type and side clearance is not measured. Second compression ring should have a side clearance of 0.09-0.12 mm (0.004-0.005 inch). Oil control ring side clearance should be 0.02-0.05 mm (0.001-0.002 inch). When installing rings onto piston, be sure manufacturer's name or TOP mark on ring is towards top of piston. Make certain notched outer edge on second compression ring is facing down. Position coil expander joint on opposite side of oil control ring gap. Stagger rings on piston so end gaps are 90 degrees apart with no gap aligned with piston pin. Piston pin - The full floating piston pin is a transition fit in piston bosses at room temperature. Heat piston prior to reassembly to ease piston pin installation. Piston pins are available in standard size only. Inside diameter of pin bore in piston should be 23.000-23.013 mm (0.9055-0.9060 inch) and maximum usable bore diameter is 23.053 mm (0.9076 inch). Piston pin diameter should be 23.002-23.011 mm (0.9056-0.9059 inch). Pin should have an operating clearance of 0.014-0.038 mm (0.0006-0.0015 inch) in connecting rod bushing. Maximum allowable clearance is 0.15 mm (0.006 inch).

Cylinder sleeves

Cylinder sleeves used in Kubota D1102, D1402 engines are dry-type sleeves which are a tight press fit in cylinder block. Sleeves which are worn beyond the allowable limit of 0.15 mm (0.006 inch) may be bored and honed to accept 0.5 mm (0.020 inch) oversize pistons and rings. When oversized sleeve is worn beyond allowable limit, sleeve must be renewed. New sleeve should be pressed into block bore until flush with top of block. New sleeves are semi-finished and must be bored and honed to obtain desired clearance of 0.075-0.100 mm (0.003-0.004 inch) for piston skirt. Standard finished diameter of sleeve is as follows: On Kubota L235, L245DT, L2350, diameter is 76.00-76.02 mm (2.992-2.993 inches). On Kubota L2550, diameter is 82.00-82.02 mm (3.228-3.229 inches).

Connecting rods and bearings

Connecting rod bearings are slipping, precision type, renewable from below after removing oil pan and connecting rod cap. When installing connecting rods, make certain match marks on cap and rod are aligned and face AWAY from camshaft side of engine. Connecting rod bolt torque is 37-41 Nm (27-30 ft.-lbs.) with threads oiled. Standard crankpin diameter is 43.959-43.975 mm (1.7307-1.7313 inches) for all models. Desired operating clearance between crankpins and bearings is 0.035-0.093 mm (0.0014-0.0037 inch) and maximum allowable clearance is 0.20 mm (0.008 inch). Connecting rod bearings are available in standard size and also 0.20 mm (0.008 inch) and 0.40 mm (0.016 inch) undersize.

Kubota L2350, L245DT, L2550, L235 - Crankshaft and main bearings

On Kubota D1102, D1402 diesel engines crankshaft and main bearing assemblies are removed from rear of engine as follows: Remove engine assembly, then remove rod and piston units, timing gear cover, crankshaft gear, flywheel and rear bearing cover. Remove bearing case retaining cap screws, then bump crankshaft and bearings rearward out of cylinder block. Note that bearing cases are minimum clearance in cylinder block bores to provide oil pressure transfer through drillings in bearing cases. Front main bearing is a one-piece bushing type, pressed into front face of cylinder block. Remainder of main bearings are two-piece bushing type contained in two-piece bearing cases. Crankshaft end play is controlled by thrust washers located on rear main bearing. Standard main journal diameter is 51.921-51.940 mm (2.044-2.045 inches). Desired diametral clearance in front main bearing is 0.040-0.118 mm (0.0016-0.0046 inch) and in remainder of bearings is 0.040-0.104 mm (0.0016-0.0041 inch). Maximum allowable clearance for all main bearings is 0.20 mm (0.008 inch). Bearings are available in standard size as well as 0.20 mm (0.008 inch) and 0.40 mm (0.016 inch) undersize.

Crankshaft end play should be 0.15-0.30 mm (0.006-0.0012 inch) with and allowable limit of 0.5 mm (0.020 inch). Thrust washers are available in standard size and also 0.20 mm (0.008 inch) and 0.40 mm (0.016 inch) oversize’s. When reinstalling thrust washers, be sure oil grooves are facing outward. Reinstall crankshaft by reversing the removal procedure while noting following items: Assemble bearing cases starting with smallest outside diameter case at front of crankshaft. Be sure to align bearing case match marks. Tighten bearing case cap screws to a torque of 30-34 Nm (22-25 ft.-lbs.) and case locating cap screws to 64-68 Nm (47-50 ft.-lbs.). Lubricate lip of rear oil seal before reinstalling rear cover over crankshaft hub. Tighten flywheel retaining cap screws to a torque of 98-108 Nm (73-80 ft.-lbs.). Crankshaft rear oil seal - The lip type crankshaft rear oil seal is contained in rear bearing cover and can be renewed after splitting tractor between engine and clutch housing and removing clutch and flywheel. Install new seal with lip towards inside and coat seal lip with grease prior to reassembly.

Flywheel

Flywheel is retained to crankshaft flange by six evenly spaced cap screws and can be installed in any of six positions. To be sure flywheel will be reinstalled correctly, remove one of the retaining cap screws and spray flywheel and exposed cap screw hole with quick drying paint. Then, when reinstalling flywheel, make certain paint marks are in register. Flywheel ring gear is a shrink fit on flywheel. Heat gear evenly prior to installation, then install with beveled end of teeth towards front of flywheel. Inspect pilot bearing and renew if necessary. Make sure mating surfaces of flywheel and crankshaft flange are clean and free of dirt, rust or burrs. Tighten retaining cap screws evenly to a torque of 98-108 Nm (73-80 ft.-lbs.).

Oil pump

The rotary type engine oil pump mounts on front of cylinder block and is driven by crankshaft gear. Pump can be removed after removing timing gear cover. To check engine oil pressure, remove oil pressure switch and install a pressure gage. With engine at operating temperature, check oil pressure at idle speed and rated speed. Pressure should be at least 100 kPa (14 psi) at idle speed and should be within range of 295-440 kPa (43-60 psi) at rated engine speed. Oil pump inner rotor to outer rotor operating clearance should be 0.10-0.16 mm (0.004-0.006 inch) and maximum allowable clearance is 0.20 mm (0.008 inch). Clearance between body and outer rotor should be 0.11-0.19 mm (0.004-0.007 inch) and a maximum allowable clearance of 0.25 mm (0.010 inch). End clearance between rotors and cover should not exceed 0.2 mm (0.008 inch). Oil pump is available only as an assembled unit. Renew complete pump if it fails to meet specifications.