Mitsubishi 4DQ3 Service Manual Download Page 20

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Item

Intake

cam

profile

(D1 -

D2)

W·

Exhaust

cam

profile

Specifications

Standard

Dt: 46.916

�gJ

(1 84708 +0.00394)

-0.01181

Dt - D2 = 6.684

(0.26315)

Dt: 45.944

(I 80882 +0.00394)

-0.01181

DI - D2 = 7.344

(0.28913)

Unit: mm tin.)

Service limit

D1 - D2 =

6.184

(0.24346)

DI - D2 =

6.844

(0.26945)

(4) Check the camshaft for runout. Straighten the

camshaft in a press or replace it, as necessary.

Specifications

Unit: mm (in.)

Item

Standard

Repair

limit

Camshaft runout

0.02 (0.0008),

0.05

max.

(0.0020)

(5) Measure the diameter of each journal in two

directions to compute the fit or clearance in the
camshaft hole.

(6) Measure the ID of camshaft holes (bushings) and

compute the fit on each journal. If the fit exceeds

the repair limit, machine the holes and install
bushings.

Checking camshaft runout

Miking camshaft journals

Summary of Contents for 4DQ3

Page 1: ...ルエンジン三菱ディーゼルエンジン MITSUBISHI DIESEL ENGINE 4DQ3 4DQ30 MITSUBISHI HEAVY INDUSTRIES LTD No 5 1 Marunouchi 2 chome Chiyoda ku Tokyo Japan Phone Tokyo 03 212 3111 Telex J22282 J22443 HISHIJU SERVICE MANUAL 99609 50000 DEC 1985 ...

Page 2: ...ubishi 4DQ3 and 4DQ30 Notes Valve Lash cold 0 25MM or 010 Head Bolt Torque 87 Ft Lbs Main Bolt Torque 62 Ft Lbs Rod Bolt Torque 40 Ft Lbs Part Number for complete gasket and seal set 3049451031 30494 51031 ...

Page 3: ...o 21 1 Compression pressure kg cm2 psi 26 369 7 min at 150 200 rpm Firing order 1 3 4 2 Direction of rotation Counterclockwise as viewed from flywheel side Burns fuel Grade No 2D diesel fuel ASTM specification Engine oil Class CC or better API service classification No of piston Compression rings 2 rings Oil ring 1 Valve arrangement Valve clearance both intake and mm in 0 25 0 0098 exhaust valves ...

Page 4: ...ecifications Unit mm in Item Standard Repair limit Warpage of gasketed 0 05 max 0 20 surface of cylinder 0 0020 0 0079 head 2 Precombustion chamberjet replacement Do not remove the jets unless they have to be re placed To remove the jet as when cracks are noted in it drive it out with a drift pin of about 6 mm 1 4 in diameter fnserted through glow plug hole as shown A Intake port C Jet a Exhaust p...

Page 5: ...ace and valve seat for wear and contact If valve face is found excessively worn reface it by using a valve refacer To reface the valve proceed as follows Item Standard Repair limit Clearance ofvalve stem in valve guide Valve guide length out side hole Valve stem diameter Specifications Item Nominal Standard Repair value limit Angle 30 Sinkage 0 2 13 Valve 0 8 0 031 0 008 0 051 seat Width 1 4 0 055...

Page 6: ...ree cutter If valve seat width exceeds 1 6 mm 0 063 in due to wear rep lace the seat Also replace the seat when valve sinkage exceeds 1 3 mm 0 051 in Valve seat installation Chill the valve seat inserts in ether or alcohol containing dry ice Heat the cylinder head to a temperature of 80 C to 100 C 176 F to 212 F Press the inserts in the cylinder head by using the insert calking tools 30691 02700 f...

Page 7: ...1 9232 l 874 Valve spring squareness 1 5 max Load compress spring to initial working len f th 19 1 15 43 mm 1 69 in 41 9 2 21 33 08 kg lb Exhaust manifold If the flange faces are warped by more than 0 2 mm 0 0079 in when checke l as shown grind them smooth and flat If any flange is found cracked replace the manifold Checking valve spring Checking valve spring for squareness Checking exhaust manifo...

Page 8: ... the repair limit rebore the sleeve to the next specifted oversize Specifications Unit mm in Item Standard Repair Service limit limit o 20 0 70 Cylinder sleeve ID 77 0 0 035 Out of 0 1 roundness 0 004 max 0 015 Taper 0 0006 max Taking ID measurements on cylinders Crankcase gasketed surfKe J 0111 0 43i t ii 1 2 3 Positions for checking sleeve bore diameter Removing ridge with ridge reamer ...

Page 9: ...ooves for stepped wear and sloped wear Replace pistons found in bad condition 2 Measure the outside diameter of piston in two direc tions perpendicular to each other If the diameter exceeds the service limit replace the piston Specifications Unit mm in Item Standard Service limit Standard 76 90 0 25 77 15 Diameter oversize 0 2 at skirt 0 50 77 40 0 008 oversize 0 75 77 65 oversize ...

Page 10: ...95 in 4 Piston rina pps Check the ring gap with a thickness gauge by placing the ring in a new cylinder sleeve and pushing the piston true and square in the bore Specifications Item Front of engine t Piston ight Piston weight marking Piston ring Gap Checking piston ring gap Unit mm in Standard Service limit 0 30 0 50 1 5 Piston ring gap 0 0118 0 0197 0 059 S Piston ring grooves Insert the compreui...

Page 11: ...ds the repair limit replace the piston pin with a new one Item Piston pin diameter Specifications Unit mm in Standard 25 0 0 006 0 984 8 00024 Repair limit 2 heck the clearance of the pin in the bushing fitted tu the small end of the connecting rod by computing the difference between the two dia meter readings If the computed difference clearance exceeds the repair limit replace the pin or the bus...

Page 12: ... 3 If the connecting rod aligner is not available the rod may be checked as follows a To check the rod for bend measure C and 2 as shown in the figur a Ifthe measure ment at C is larger than 0 05 mm per 100 mm 0 00197 in per 3 937 in of 2 straighten the rod with the use ofa press b To check the rod for twist measure C as shown in the figure b Ifthe measurement at C is larger than 0 05 mm per 100 m...

Page 13: ...ckness gauge to measure the end play which is the clearance between big end and crank arm If the clearance measured exceeds the service limit replace the connecting rod or bearing Specifications Unit mm in Item Standard Service limit Connecting rod 0 15 0 35 0 50 end play 0 0059 0 0138 0 0197 6 Check the bearings as follows a Inspect each bearing for evidence of wiping or fatigue failure for scrat...

Page 14: ...g connecting rod bearing c Check the contact pattern of bearing on crankpin by fitting the big end in the normal manner to the crankpin with the crankshaft laid out on the bench and by using a paste of red lead or Prussian blue to visualize the con tact Be sure to tighten the cap bolts to the specified torque that is 5 5 kg m 39 8 lb ft The contact should occur over at least 75 of the entire surfa...

Page 15: ...using a surface grinder to make it flat within the specified standard Specifications Item Standard Warpage of crankcase 0 05 max gasketed surface Crankshaft 1 Journals 0 0020 Unit mm in Repair limit 0 20 0 0079 a Inspect each journal for surface flaws such as roughing scratches pitting and bums and as necessary repair the journals by grinding to the next undersize or replace the crankshaft b Mike ...

Page 16: ... exceeded repair by grinding to the next undersize or replace the crankshaft Specifications Unit mm in Item Diameter of journals Out of round ness of crank pins andjournals Taper of crank pins andjournals Diameter of crankpins Fit ofjournals in main bearings Standard 65 0 0lS 0 035 2 559 o ooos9 _ 0 00138 O Ql 0 0004 max 58 o oJs 0 0SS c2 28ro 001Js 0 00217 0 03 0 089 0 0012 0 00350 Repair Service...

Page 17: ...ge a fillet radius is sure to cause the bearing to ride on the radius and thereby to result in a bearing failure Be extremely careful not to grind off the radius part beyond the desired dimension An over ground radius part can be corrected only by grinding off the shoulder face and this if effected will present problems in obtaining a proper end clearance Also check the crankpins and journals for ...

Page 18: ...ence between the width of thrust bearing and the dimension A indicated below 4 Runout Support the crankshaft as shown and roll it to measure its deflection with a dial gauge Distor tion is one half of the deflection dial gauge reading if it exceeds the standard reduce it by bending the crankshaft in a press Specifications Unit mm in Item Standard Repair limit Crankshaft runout 0 02 0 05 0 0008 max...

Page 19: ...dings compute the radial clearance Specifications Unit mm in Item Standard Repair limit Fit of main bearings on 0 03 0 089 0 200 journals 0 0012 0 00350 0 00787 Camshaft 1 Check the camshaft end play as outlined for the timing gears Where the end play exceeds the repair limit replace the thrust plate with a new one Specifications Unit mm in Item Nominal Standard Repair value limit Camshaft end 5 0...

Page 20: ...r runout Straighten the camshaft in a press or replace it as necessary Specifications Unit mm in Item Standard Repair limit Camshaft runout 0 02 0 0008 0 05 max 0 0020 5 Measure the diameter of each journal in two directions to compute the fit or clearance in the camshaft hole 6 Measure the ID of camshaft holes bushings and compute the fit on each journal If the fit exceeds the repair limit machin...

Page 21: ...appet holes Service limit 0 1 0 004 1 Inspect the riding face of each tappet for wear contact pattern and crack Replace defective tappets 2 Check the fit of the tappet in the hole against the repair limit indicated below If the limit is exceeded then replace the tappet If the hole is worn down so much as to provide an excessive radial clearance even with a new tappet the crankcase must be replaced...

Page 22: ...nd play with a thickness gauge Replace the thrust plate to reduce the play if the thickness gauge reading exceeds the repair limit Specifications Unit mm in Item Standard Repair limit Idler end play 0 05 0 15 0 35 0 0020 0 0059 0 0138 4 If the idler shaft has to be replaced use the idler shaft puller to remove it as shown When installing the replacement shaft check to be sure that the oil holes ar...

Page 23: ... or otherwise defective d Idler gear Inspect the idler gear teeth and as necessary replace the gear 6 Inspect the gear case for cracks and for evidence of oil leakage at the part ahead of the crankshaft A cracked case must be replaced Inspect thecrank shaft pulley too examining condition of surface in contact with the oil seal and checking the keyway and key for wear Replace the pulley if found in...

Page 24: ...y slowly inserting piston pin into piston Insert snap ring in one end in advance Install connecting rod to piston so that the marking side ofthe connecting rod big end comes to the camshaft side c Install compression rings and oil control ring by using piston ring tool Combustion chamber side Camshaft side Marking side PISTON AND CONNECTING ROD ASSEMBLY ...

Page 25: ...three camshaft bushings 1 into camshaft holes in crankcase by using adapter A If the fit exceeds the repair limit machine the holes and install bushings b Drive idler shaft 2 into crankcase by using installer B Driving in DRIVING IN CAMSHAFT BUSHING ...

Page 26: ...ne oil in the internal surface of bearing and on the external periph ery of piston Position piston rings so that ring gaps are located 90 in respect with each other as shown and then insert piston assembly 2 into crankcase Alignment marks on the connecting rod must face the camshaft side Put cap attaching bolts 3 into rod in advance Insert piston assembly into crankcase by us ing piston guide A No...

Page 27: ... I to main bearing cap 2 front center and rear and install the cap in place aligning it with dowel pin A of crankcase b Measure the crankshaft end play with a thickness gauge Replace No I main bearing if the end play is out of specification Tighten main bearing cap bolts 3 to a torque of 8 5 kgm 61 463 lb ft 6 Install the connecting rod bearing caps as follows a Install connecting rod bearing lowe...

Page 28: ...e external peripheries of main bearing caps No 1 and No 3 with the flange facing the case inside b Apply ThreeBond 1102 adhesive on both sides of oil pan gasket 2 and attach it to crankcase Make sure that the gasket is completely attached in the grooves A in the caps c Apply Atomjet on the both ends of rubber packing 3 and insert the packing into cap ...

Page 29: ...e bearing cap Tighten the bolts to a torque of 0 4 kgm 2 9 lb ft 8 Install the front plate as follows a Apply ThreeBond 1102 to the both sides of front plate packing and attach the packing to the front face of crankcase Secure front plate 1 with in jection pump installed with two bolts 2 The tightening torque of the bolts is 2 1 kgm 15 2 lb ft b Heat camshaft gear to 150 C to 180 C and fit it to s...

Page 30: ...ows Direction of rotation Using a 3 mm 0 12 in thick smooth steel plate add 3 mm 0 12 in clearance to intake and ex haust valves of No 1 cylinder Then insert a 0 05 mm 0 0020 in thickness gauge into between the top of valve cap and rocker and slowly turn the crankshaft trying to find a position where the thickness gauge is firmly gripped the valve starts opening and a position where the gauge is j...

Page 31: ...the rear plate and flywheel as follows a Drive in dowel pin 1 and secure flywheel 2 complete with pilot bearing in place with bolts 4 and lock washers 3 b Bend lock washers properly to lock bolts Flywheel bolt tightening torque Unit kg m lb ft 8 5 0 5 61 5 3 6 13 Reassemble the cylinder head as follows a Drive valve guide 2 into cylinder head 1 as shown I B 1 Cylinder head 2 Valve guide A Valve gu...

Page 32: ...ylinder head 14 Install the cylinder head assembly as follows a Place the gasket 1 to crankcase 2 and install cylinder head 3 Use two guide bolts 4 to prevent the gasket from moving when placing cylinder head to the crankcase CAUTION Do not apply any sealant to the gasket b Tighten the cylinder head bolts to a torque of 12 kg m 86 8 lb ft at exhaust side and at intake side in the sequence shown be...

Page 33: ... 0 25 mm 0 0098 in for both intake and exhaust valves This value assumes that the engine is at normal tempera ture there being no temperature difference throughout the body of the engine The checking and adjusting procedure is as follows a Rotate the crankshaft slowly to bring the piston in No 1 cylinder to Top Dead Center TDC This can be accomplished by observing rocker arms of No 4 cylinder As y...

Page 34: ...he water pump pulley and crankshaft as follows a Drive in water pump pulley l and crankshaft pulley 2 by using installers A and B b After driving in the crankshaft pulley install washer and tighten nut Then bend the lock washer to lock the nut 21 Install the alternator 22 Install the fan belt as follows a Attach fan belt to the pulley b Adjust the fan belt tension in such a way to have a slack of ...

Page 35: ...ankcase at its right hand rear portion Its main shaft is driven from the skew gear formed of the camshaft 2 1 Disassembly I Loosen bolts securing oil strainer 2 and separate the strainer from oil pump case 2 Loosen bolts 3 securing oil pump cover 4 and separate the cover from oil pump case 3 To facilitate removal of outer rotor 5 turn the pump case upside down 4 Drive out pump drive gear taper pin...

Page 36: ...l clearance between outer rotor and pump body Insert a thickness gauge into between outer rotor and body If the clearance checked is greater than the limit replace the worn part Specifications Unit mm in Item Standard Repair limit Clearance of outer 0 2 0 275 0 50 rotor in body 0 0079 0 01083 0 020 4 Rotor shaft diameter Inspect the shaft for damage and check it for wear by miking Determine the av...

Page 37: ...e element is actually a relief valve located in the center portion of the element This valve is set to open when the differential pressure across the element rises to 1 0 0 2 kg cm2 14 2 2 8 psi when the valve opens the oil flows directly from inlet side to outlet side The filter element must be serviced regularly or before the element becomes so dirty as to actuate this bypass valve The oil filte...

Page 38: ...s the rising coolant temperature reaches 76 5 C 169 7 F the thermostat valve begins to open increas ingly wide and the coolant begins to flow to radiator at a rising rate of flow with a corresponding decreases in the amount of coolant being bypassed As the tem perature reaches 90 C 194 F the valve becomes full open shutting orf the bypass passage 2 Thermostat The thermostat is of wax type designed...

Page 39: ...C 169 7 3 6 F that makas valve start opening T2 Temperature 90 2 C 194 3 6 F that makes valve fully open with a lift of not less than 9 mm 0 35 in I Thermostat performance curve The water pump is of centrifugal type Its bearings are r lubricated by engine oil fed from the main gallery within the crankcase Theimpeller is threadedly mounted on the pump shaft 3 1 Disa mbly 1 Remove pump cover 2 by lo...

Page 40: ...t check for the cause The impeller and case or cover if found damaged due to rubbing must be replaced with new ones 3 Check the unit seal for condition Replace the seal if it is badly worn or damaged 4 Check the pump shaft bearing journals for wear Replace the shaft if the journals are excessively worn 5 Check those surfaces of pump case to which the bearings are fitted for excessive wear or damag...

Page 41: ...nd install the shaft in pump case 3 2 Install snap ring 4 in case on pulley side 3 Install unit seal 5 in impeller 6 and secure the impeller to the shaft 4 Install cover 7 5 Rotate the shaft to check to see that the impeller does not interfere with cover ...

Page 42: ...ne is in good condition c Color of exhaust gases d Leakage of cooling water e Leakage of fuel oil f Fuel injection 3 Running in the engine While running in the engine check the following items and repair if necessary a Oil pressure 3 4 kg cm2 or 42 7 56 9 psi b Temperature of cooling water 75 85 C or 167 185 F c Temperature of lubricating oil 60 70 C or 140 158 F in oil pan d Abnormal noise e Exce...

Page 43: ...m2 43 57 psi 2 kg cm2 at 1500 rpm 28 4 psi 1 2 kg cm2 14 2 28 4 psi min 0 5 kg cm2 at idle speed 7 1 psi 24 ATDC 4 BBDC 30 16 BBDC 28 BTDC 1 Ene ine specifications rpm 11500I1800I200012200 l 2500J 3000 l 36001 l 1JTIX n I 23 I 24 I 2s I 26 l 28 I 30 I 33 I 0 05 0 0020 max 0 20 Regrind if warpage is 0 008 minor 77 3 307 g 035 tg 00138 0 20 0 70 0 008 0 0276 Hone sleeve to 0 25 0 0098 0 50 0 00197 o...

Page 44: ...1 Replace crankcase and 0 0079 0 9 0 035 limit is reached bearing cap as an assembly Regrind crankshaft 0 Q35 0 100 at crankshaft journals and use under 2 Upper bearing shells have 0 00138 0 00394 1 journal aD size bearings 0 25 oil groove 0 0098 0 50 0 0197 1 or 0 75 0 0295 if service limit is reached 0 E9rH I 0 1 0 189 1 0 004 0 00744 0 30 1 0 0118 Replace thrust bearing 8 033 tg OO13O 0 10 0 00...

Page 45: ... 0 20 J repair limit is reached 0 00276 0 00413 0 0079 0 a C Valve sinkage L3 to 0 8 0 031 0 2 0 008 Go 0 051 c C 3 Margin valve head 1 f I 1 7 0 067 1 2 a thickness 0 047 Refacing limit Face runout of stem 0 03 0 0012 max prependicularity to valve face Valve guide length 18 0 709 0 3 0 012 outside hole Valve seat angle 30 Valve seat width 1 4 0 055 0 14 O OOSS 1 6 0 063 Free length 48 85 1 9232 4...

Page 46: ...9 65 2 559 5S 2 2S3 3 0 12 Unit mm in Assembly standard Repair limit Service limit Standard clearance Clearance Clearance Remedy Remarks 0 25 0 009S clearance may also be obtained by warm set ting if intake and exhaust valves are at the same temperature g 061 tg 00240 0 016 CO 00063 0 034 0 00134 Replace bushings if 0 016 0 095 1 0 10 J repair limit is rcached 1 0 00063 0 OO374 J 0 0039 Replace sh...

Page 47: ...0 CJ oversize E Q C 0 75 0 0295 E oversize 77 65 Protrusion above crankcase Difference in weight among pistons per engine 0 015 0 2 0 35 0 75 0 0138 0 0295 5 g 0 18 oz Check bcarin clearance u t m mm m Measure in the direction transverse to piston pin I 1 Q t 7 l ...

Page 48: ...94 1 Repair limit Service limit Remedy Clearance Clearance I 1 5 I 0 059 I 0 20 I 0 0079 Replace rings if service limit is reached Re place pistons if the limit is exceeded I 0 15 I 0 0059 Replace piston pin if I o o5 I repair limit is reached 0 0020 Replace piston if the limit is exceeded I 0 08 I Replace piston pinor bush 0 0031 ing Ream if necessary 0 15 100 0 0059 4 Replace bearings if repair ...

Page 49: ... 0 02 0 0008 max 1 0 05 0 112 1 0 00197 0 00441 0 025 t0 00098 0 0 0 025 Co 00098 0 050 0 00197 0 025 0 075 lco 00098 0 00295 1 0 05 0 15 0 0020 0 0059 I o 50 I 0 0197 0 5 0 020 0 05 0 0020 I o 3 I 0 012 I o 1 I 0 004 I o 35 I 0 0138 Unit mm in Replace connecting rods Grind or replace 1 I Replace flywheel D1 D2 6 184 0 24346 Replace camshaft D1 D2 6 844 0 26945 D2 Straighten or replace Replace thr...

Page 50: ... 5945 13 0 5118 3 0 kg cml 42 7 psi Assembly standard Standard clearance 0 05 0 15 I Q0020 o 0059 0 09T 0 045T l 0 0035T 0 0018T I 0 05 0 20 0 0020 0 0079 I 0 013 0 o15 0 00051 0 00059 I 0 04 0 09 I 0 0016 0 0035 I 0 20 0 275 l 0 0079 0 01083 0 0 0 15 0 0059 0 032 0 074 lco 00126 o 0029nl 0 2 kg cm2 2 84 psi Repair limit Clearance 0 35 0 0138 0 25 0 0098 l o 15 I 0 0059 Unit mm in Service limit Cl...

Page 51: ...pply to the whole surfaces at reassembling Gear case Apply when reassembling Timing gear case ThreeBond 1102 temporarily gasket Front plate Apply to the whole surfaces at reassembling Plate Apply when reassembling Water pump gasket ThreeBond 1102 temporarily Water pump Apply to the whole surfaces at reassembling Plate Apply when reassembling Pump plate gasket ThreeBond 1102 temporarily Crankcase A...

Page 52: ... 2 3 6 Timing gear case bolts 1 0 0 5 7 2 3 6 Camshaft thrust plate bolts 1 8 0 5 13 0 3 6 Idler thrust plate bolt 3 5 0 5 25 3 3 6 Crankshaft pulley nut 40 0 t 0 5 289 3 3 6 Rear plate bolts 3 5 0 5 25 3 3 6 Rear oil seal bolts 0 4 2 9 Flywheel bolts 8 5 0 5 61 5 3 6 Oil pan bolts 0 7 5 1 Oil pan drain plug 10 0 0 5 72 3 3 6 Nozzle holder retaining nuts 5 0 0 5 36 2 3 6 Injection pump delivery va...

Page 53: ...nd including 14 kg m 101 lb ft has a tolerance of 20 and a torque above 14 kg m IOI lb ft has a tolerance of 15 Tightening torque With spring washer Without spring washer Diameter Pitch kgf m lbf ft kgf m lbf ft 8 1 0 1 8 1 2 2 16 1 25 1 8 13 2 1 15 10 1 25 3 6 26 4 2 30 1 5 3 4 25 4 0 29 12 1 25 6 5 47 7 6 55 l 75 6 0 43 7 1 51 14 1 5 10 4 75 12 2 88 2 0 9 8 71 11 5 83 16 1 5 15 8 114 18 6 135 2 ...

Page 54: ...OLS Drawing or sketch Ot 1C 55 Material S53C o sc 1C 188 Material S53C Unit mm Used for Installing valve guides 1 Valve guide installer 2 Valve guide I 3 Cylinder head A Guide length outside hole Removing valve guides 1 Valve guide remover 2 Valve guide 3 Cylinder head Installing I intake valve inserts valve ins rts I 1 Caulking body 4 Valve guide 2 Valve insert 5 Caulk ng ring 3 Cylinder head A ...

Page 55: ...1800 Idler shaft puller Cranking handle 34491 00300 Socket Drawing or sketch Gt Unit mm Used for Connecting pressure gauge to engine for compression measurement Removing idler shaft Rotating crank pulley for engine cranking Installing camshaft thrust plate ...

Page 56: ...Tool name 30091 01101 Universal extension 31391 12900 Piston ring tool Idler bush 30691 51900 ing puller Drawing or sketch Gt Unit mm Used for Removing installing piston rings Removing installing idler bushing ...

Page 57: ...Sleeve installer set Drawing sketch Adaptor MH061080 Adaptor MH061081 31391 12300 Ot Unit mm Used for Removing installing camshaft bushings 1 Rod 3 Camshaft bushing 2 Adaptor To be used together with guide piece 30891 04700 as a set Installing crankshaft rear oil seal sleeve ...

Page 58: ...iming too retarded Defective governor control spring Maladjusted governor damper spring Engine speed too low Failure of engine to stop properly Poor grade of fuel oil Fuel viscosity too high Poor grade of oil Oil viscosity too high Oil viscosity too low Low oil pressure Excessive oil leakage Pumping up of oil Clogged oil filter Defective oil indicator switch or lamp Insufficient air Poor compressi...

Page 59: ... 0 0 0 0 Remedy Check and replace if necessary Replace nozzle tips Check and replace spring if necessary Then adjust governor setting on bench Adjust Adjust idling set bolt Hold lever in STOP position Use fuel for cold weather Use good quality oil Use proper viscosity oil Use proper viscosity oil Retighten and replace packing if necessary Change element and oil Check and replace if necessary Adjus...

Page 60: ...age drop Open circuit in heater plugs or pilot lamp Short circuit in heater plugs Defective alternator Defective alternator relay Improper wiring Jammed moving parts Worn cylinders pistons or piston rings Sticking piston rings Excessive main bearing clearance gi Loose connecting rod cap bolts E Interference between valve and piston Broken valve springs Excessive valve clearance Foreign substances ...

Page 61: ...ck for connections and repair Replace if necessary Repair or replace if necessary Repair or replace Repair or replace motor if necessary Repair or replace ring gear Replace pinion Recharge or replace battery If necessary heat it Replace Replace copper packings and if necessary heater plugs Replace alternator if necessary Adjust or replace Connect wires properly Repair or replace Repair or replace ...

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Mitsubishi 4DQ3, Service Manual

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