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974-0750 Onan MDJA to MDJF Marine Diesel Engine Service Manual

1. 0014 0052 04 13 Connecting Rod Journal 2 0597 2 0605 52 316 52 337 Rod Bearing Clearance 5 tenet HH ehe nnn 001 0033 025 084 End dani Ea ados REC RES 010 015 254 381 PISTONS AND RINGS Clearance in Cylinder Measure 90 to pin just below oil ring Prior to SPC P eren ka teenie dana S bad 0050 0070 127 178 Begin Spe Pr 0055 0075 140 191 Ring Groove Width TOD oi Sosa vaa o ace Diae eara i nne CHR E ed E ELE dA RELEASE 0970 0980 2 464 2 489 hw PE 0965 0975 2 451 2 477 tes we pero PE e Kane one ami pri ERR UE RET EE Ee 0965 0975 2 451 2 477 m 1880 1897 4 775 4 818 Ring e se ae 010 020 25 51 PISTON PIN Clearance in PISIN ss se ceco ee re rh den cas ote me ena video acelin nh n e pv V Thumb push Fit Connecting Rod Bushing Clearance 0002 0007 005 018 STARTING MOTOR Prestolite Rotation oor e ku t SS Deleted d ee Counterclockwise Pinion Clearance to Pinion Stop Solenoid Plunger 070 120 1 78 3 05 Armature E
2. Factory code for general identification purposes 2 Specific TYPE as follows R REMOTE type Electric starting Optional accessory equipment can be connected for 2 wire remote control of starting and stopping E ELECTRIC start type Electric starting at the plant only 3 Factory code for specific optional equipment supplied 4 Specification Spec Letter Advances with fac tory production modifications Specifications All dimensions in U S customary units of measure metric in parentheses unless otherwise specified UNIT OF SPECIFICATION MEASURE MDJB MDJC MDJE MDJF Number of Cylinders 1 2 4 2 4 Diesel Fuel ASTM2 D ASTM2 D ASTM2 D ASTM2 D ASTM2 D Bore in 3 25 3 25 3 25 3 50 3 50 mm 82 55 82 55 82 55 88 9 88 9 Stroke in 3 625 3 625 3 625 3 625 3 625 mm 92 07 92 07 92 07 92 07 92 07 Displacement cu in 30 60 120 70 140 litre 0 5 0 98 1 9 1 2 2 3 Compression Ratio 19 to 1 19 to 1 19 to 1 19 to 1 19 to 1 Firing Order 1 2 4 3 1 2 4 3 Crankshaft Rotation viewed from flywheel Clockwise Clockwise Clockwise Clockwise Clockwise Governor Variable Speed Mechanical Variable Speed Mechanical Valve Clearance Cold Spec A C Begin Spec D Intake in 0 020 0 010 0 015 0 011 0 017 0 017 mm 0 51 0 25 _ 0 38 0 28 0 43 0 43 Exhaust in 0 020 0 010 0 013 0 016 0 017 0 017 mm 0 51 0 25 0 33 0 41 0 43 0 43 Oil Filter Full Flow Full Flow Full Flow Full Fl
3. Bleeding Fuel System After replacing or cleaning the filters bleed the fuel system of air Bleed air from fuel system as follows 1 Disconnect fuel return line at the tee near the transfer pump Use container to catch fuel 2 Operate hand priming lever on diaphragm type fuel transfer pump until there are no air bubbles in fuel flowing from the fuel return line Figure 58 If fuel tank is disconnected use a separate container of fuel andconnecta short hose line between the transfer pump inlet and the fuel container The pump has enough suction to the fuel out of the container 1 NOZZLE CONNECT RETURN LINES FUEL RETURN SHADED LINE HERE GOVERNOR POST FLEXIBLE LINE AND ARM ASSEMBLY 8464 HIGH PRESSURE LINES FIGURE 57 FUEL LINES TO INJECTORS WORK TRANSFER PUMP PRIMING LEVER UNTIL FUEL FLOWS FROM RETURN LINE OF INJECTION PUMP FIGURE 58 BLEEDING FUEL SYSTEM If the camshaft transfer pump lobe is up crank engine one revolution to permit hand priming When finished return priming lever inward disengaged position to permit normal pump operation Connect the fuel return line at tee A diesel engine cannot tolerate dirt in the fuel system Dirt is one of the major causes of diesel engine failure A tiny piece of dirt in the injection system may stop your unit When opening any part of the fuel sys tem beyond the secondary fuel filter place all parts in a pan of clean diesel fuel as
4. IMPORTANT For complete customer satisfaction repaint unit Onan White spray can 525 0216 and apply instructions from Marine Kit Maintenance Check the valve clearances at regular intervals see OPERATORS MANUAL In addition clean the com bustion chambers and valve seats as required if engine loses power or has low compression Valve Clearance Adjustments After engine has reached a stable temperature condi tion the valve clearances may be adjusted It is recommended that the valve clearance be set with engine at room temperature about 75 F 24 C Allow at least two hours cooling time after engine operation 1 To adjust valve clearance on two cylinder J Ser ies engine proceed as follows A Turn flywheel until cylinder which is to have its valve adjusted is on a compression stroke which follows closing of intake valve B Turn flywheel until TC top center mark on flywheel lines up with timing pointer on gear cover Then turn flywheel in a clockwise direction for an additional 10 to 45 degrees The timing mark for this position must be established in this position the piston will be in its power stroke with both valves com pletely closed C Using atfeeler gauge check clearance between rocker arm and valve Figure 100 Increase or reduce clearance until proper gap is estab lished adjust with lock nut which secures rocker arm to cylinder head Figure 101 Refer to SPECIFICATIONS for correct valve clear
5. seb au eae 4 Assembly Torques and Special 6 Engine Troubleshooting 7 Service and 8 Exhaust System olea IR Er oes cece wes celeb eee seeta 14 Cooling System eere rr ee e e iv e ee m eser nia e oe adele eye nn n 16 Fuel System ERE ES 36 Governor System oie does esas seis sen dene ye ve ner E 60 Oil System Ee Ro EXER 5 62 Starting System oi rs ode ee reu 68 Engine 5 75 INCORRECT SERVICE OR REPLACEMENT OF PARTS MIGHT RESULT IN SEVERE PERSONAL INJURY AND OR EQUIPMENT DAMAGE SERVICE PERSONNEL MUST BE QUALIFIED TO PERFORM ELECTRICAL AND OR MECHANICAL SERVICE General Information INTRODUCTION This manual deals with specific mechanical and elec trical information needed by engine mechanics for troubleshooting servicing repairing or overhauling the engine Use the table of contents for a quick reference to the separate engine system sections Use the separate Parts Catalogs available at the dealer level for parts identification and for establish ing their proper location on assemblies The TROUBLESHOOTING GUIDE provides a quick reference for locating and correcting engine trouble The illustrat
6. ROCKER ARM BODY PRIMING LEVER ROCKER ARM LINK FIGURE 30 FUEL TRANSFER PUMP Fuel pump pressure may be checked by connecting a pressure gauge and tee at the fuel outlet A vacuum gauge connected at the fuel inlet will show whether the pump has enough capacity to lift fuel about6 feet 1 86 m The fuel pump should produce 15 to 18 inches 381 to 457 mm of vacuum at sea level Fuel Pump Removal Disassembly 1 Remove pump inlet and outlet lines Remove two capscrews holding pump to engine and lift it off 2 Notch the pump cover and body with a file so they can be reassembled in same relative positions and remove six screws holding them together 3 Tap body with a screwdriver to separate two parts Do not pry them apart this would damage diaphragm 4 Drive out rocker arm hinge pin Remove rocker arm spring and fink 6 Lift out diaphragm assembly and diaphragm spring C Repair A kit is available for replacement of the diaphragm and spring If the diaphragm is leaking or broken check for diluted crankcase oil necessary replace diaphragm Occasionally a worn rocker arm pin will cause crankcase oil leakage If this is the case the pump should be replaced Assembly 1 When installing a new diaphragm soak it in fuel before assembling Insert diaphragm spring and soaked diaphragm into pump body 2 Insert link and rocker arm into body and hook it over diaphragm pull rod Align rocker arm with r
7. See the DIMENSIONS AND CLEARANCES section if the proper clearances cannot be obtained by replacing the valves replace the valve guides Drive the old valve guides into the valve chambers Drive new guides in until they protrude 11 32 inch 8 731 mm from the rocker box side of the head Ream the new valve guide to obtain the proper clearance Valve Seats If valve seats are pitted refinish them Using conventional seat grinding equipment reface each seat to a 45 degree angle and a seat width of 0 047 to 0 062 inch 1 191 to 1 588 mm You should be able to reface each seat several times before it becomes necessary to replace it If the valve seats are loose or cannot be refaced replace them Use Onan tool number 420 0272 in a drill press Fig ure 102 to remove each valve seat Adjust the tool to cut 1 64 inch 0 397 mm from the edge of the seat Oil the pilot to prevent it from seizing in the valve guide Cut each seat down to a narrow rind on edges and bottom and break it out with a sharp tool Be careful not to cut into the counterbore bottom BE SURE TO OIL PILOT OF TOOL AFTER CUTTING RIND tS EASILY REMOVED i MAKE CUT he 1 64 397 mm FROM EDGE OF SEAT FIGURE 102 REMOVING VALVE SEATS Thoroughly clean the valve seat counterbore and remove any burrs from the edges the counterbore is damaged it will have to be machined for an over size seat Oversize seats are available in
8. wheel should be between 10 degrees and 45 degrees past BC G After timing number 3 cylinder adjust valve clearance according to Step 1C Testing The cylinder compression test can be used to deter mine the condition of valves pistons piston rings and cylinders To check compression run the engine until tho roughly warm Stop engine and remove all injection nozzles Insert the compression gauge in one nozzle hole Crank the engine and note the reading To check for piston blow by squirt a small amount of SAE 50 oil into the cylinder and repeat the check An increase in compression with oil in the cylinder indi cates piston blow by Compression of a standard new engine cranking at about 300 rpm is about 300 350 psi 2070 to 2415 kPa prior to Spec and 350 400 psi 2415 to 2760 kPa Spec P and later Compression should be fairly uni form normaily with less than 10 psi 69 kPa differ ence between the highest and lowest cylinder taken at the same cranking rpm Excessively high readings indicate carboned combustion chambers Compression readings will deviate considerably from the above readings because of differences in crank ing speed altitude and ambient temperature condi tions Therefore the specification is given only as a guide The best indication of leakage is the pressure difference between cylinders or a compression increase when oil is added to the cylinder CYLINDER HEADS VALVES DISASSEMBLY
9. 7 srALL POS ITION OF BRAKE ARM 12 STORAGE BATTERY FIGURE 87 TESTING STALL TORQUE High free speed with iow developed torque and high current draw indicates shorted fields Since there is no easy way to detect shorted field coils replace and check for improved performance The voltage drop across the solenoid on the starting motor should be less than 0 3 volts If not remove it for repair BATTERY Engines with a separate cranking motor normally use a single 12 volt battery of at least 62 amp hour capacity The battery charging system maintains the batteries at or near full charge at all times Inspect the battery charging system and adjust the charge rate if batter ies appear to be continually discharged Adding accessories that draw battery current requires an adjust ment of the charge rate If discharge or failure to charge cannot be traced to the battery charging system thoroughly inspect and test the battery and replace it as necessary REPAIR Armature inspect the armature for mechanical defects before checking for grounds or shorted coils To test for grounds use a 12 volt test lamp and check between each segment of the commutator and the shaft Do not touch probes to the commutator brush surfaces as this will burn the smooth surfaces A growler is necessary to test for shorted coils With the armature on the growler run asteel strip over the armature surfaces If a coil is shorted th
10. A new gasket is required for reassembly of adapter to prevent oil leaks 4 Thoroughly clean adapter assembly before re placing new bearings and oil seal 5 Place adapter assembly in suitable holder for removing and installing bearings and seal Do not clamp in a vise unless machined surfaces are protected from damage by the jaws of the vise 5 PRESS DOWN TO is im REMOVE SEAL E 25 TOP BEARING RETAINER CLIP ee BOTTOM BEARING ADAPTER BOSS YOKE SHAFT YOKE i Poe SEAL SPACER BEARING SPACER SLEEVE SLEEVE FIGURE 62 BEARING INSTALLATION AND TOOL PACKAGE 420 0374 Bearing and Seal Replacement Procedure After adapter assembly has been removed from the engine replace the bearings and seal on the yoke shaft as follows 1 Referring to Figure 62 press shaft and yoke assembly towards center of adapter until shaft and bottom bearing slips out bottom end 2 Using solid end of bearing driver press top bear ing and seal out bottom end 3 Remove external retaining ring and slide bearing off yoke shaft 4 Thoroughly clean and oil yoke and shaft assem bly and adapter for installing new bearings and seal 5 Install bottom bearing from top of adapter cast ing using hollow end of bearing driver Make sure lettered side of bearing faces upward and that tool bottoms against top of adapter boss 6 Slide yoke and shaft assembly up through bear ing then suppo
11. BEARING P gu 3 ua CPU PRESS BEARING FLUSH WITH FRONT CRANK CASE SURFACE 248 X 3 2 mm ALIGN OIL HOLES FRONT BEARING FIGURE 112 CAMSHAFT BEARINGS CAMSHAFT PRESSED IN SPACER s CAMSHAFT GEAR ae ce KSHAFT gt d PULLED OUT FIGURE 113 CAMSHAFT ENDPLAY 2 1 4 x 20 PULLER THESE MARKS MUST COINCIDE WHEN INSTALLING TIMING GEARS FIGURE 114 TIMING MARKS 85 Press new bearings into piace Figure 112 Press the rear bearing flush with the bottom of the expansion plug recess Press the front bearing in flush with the crankcase front surface so the oil passages are aligned Do not attempt to ream the bearings as they are a precision type After rear bearing is installed insert a new expansion plug in the recess using seal ing compound and expand it into place with sharp blows at its center Installation Camshaft Assembly 1 Install key and press camshaft gear on camshaft until it bottoms on flange with no clearance 2 Install governor components 3 Slide thrust washer onto shaft Measure camshaft end play it shouid be 0 007 to 0 039 inch 0 178 to 0 991 mm See Figure 113 4 Lay engine on its side or end and insert push rod tappets 5 Install camshaft assembly in engine Align timing marks on camshaft gear and crankshaft gear See Figure 114 6 Replace push rods and fuel transfer pump 7 When engine is reassembled ins
12. Batteries e Before starting work on the engine disconnect batteries to prevent inadvertent starting of the engine e DO NOT SMOKE while servicing batteries Lead acid bat teries give off a highly explosive hydrogen gas which can be ignited by flame electrical arcing or by smoking Verify battery polarity before connecting battery cables Connect negative cable last Fuel System DO fill fuel tanks while engine is running DO NOT smoke or use an open flame in the vicinity of the engine or fuel tank Internal combustion engine fuels are highly flammable Fuel lines must be of steel piping adequately secured and free from leaks Piping at the engine should be ap proved flexible line Do not use copper piping for flexible lines as copper will work harden and become brittle enough to break e Be sure all fuel supplies have a positive shutoff valve Exhaust System e Exhaust products of any internal combustion engine are toxic and can cause injury or death if inhaled All engine applications especially those within a confined area Should be equipped with an exhaust system to discharge gases to the outside atmosphere DO NOT use exhaust gases to heat a compartment Make sure that your exhaust system is free of leaks En sure that exhaust manifolds are secure and are not warped by bolts unevenly torqued Exhaust Gas Is Deadly Exhaust gases contain carbon monoxide a poisonous gas that might ca
13. Keep the electrolyte at the proper level above the plates by adding distilled water Check specific gravity recharge if below 1 260 DUST AND DIRT 1 Keep inlet screen free of dirt etc 2 Service air cleaner as frequently as necessary 3 Change crankcase oil every 50 operating hours 4 Keep oil and fuel in dust tight containers 5 Keep governor linkage clean HIGH ALTITUDE Maximum power will be reduced approximately 4 percent for each 1000 feet 310 m above sea level after the first 1000 feet 310 m 11 LOW TEMPERATURES 1 Use correct SAE No oil for temperature condi tions Change oil only when engine is warm If an unexpected temperature drop causes an emer gency move engine to a warm location or apply heated air never use open flame externally until oil flows freely 2 Use fresh fuel Protect against moisture conden sation 3 Keep fuel system clean and batteries in a well charged condition 4 Use additional preheat cycles during cold starts Do not exceed one minute preheat periods longer periods can ruin the heater elements OPERATOR AND SERVICE MAINTENANCE SCHEDULE HOURS OF OPERATION MAINTENANCE TASK 50 more often in dusty conditions Inspect exhaust system Inspect engine Check fuel supply see Note 1 Check oil level See Figure 2 Check air cleaner Clean governor linkage Change crankcase oil Drain fuel condensation traps in lines and filters 1
14. MDJE Spec A AA MDJF w o heat exchanger LOCKING BODY DRAIN IMPELLER PLUG 4 BELLOWS ASSEMBLY BOLT PEDESTAL SHAFT AND BEARING zzii 0 4 WEAR SNAP UD FACE SEAT FIGURE 19 PUMPS 1132 0110 AND 7132 0074 25 WATER PUMPS 7132 0110 and 8132 0074 Pumps 132 0110 and 14132 0074 are centrifugal pumps with metal impellers Figure 19 Disassembly 1 Remove the water inlet fitting drive belt pulley cover screws and pump cover gasket 2 Unscrew the threaded impeller from the pump shaft by turning the impeller in a counterclock wise direction when facing impeller 3 Slide the seal seat wear face and bellows assembly off the shaft Loosen the clamp screw and slide the pump body off the pedestal 4 Remove the bearing lock ring and drive the shaft and bearing assembly out of the pedestal The bearing is press fit on the shaft and comes off in one integral part The bearing is packed with a lifelong lubricant and is sealed at each end Assembly Replace all worn components such as bearings seals wear face and impeller and use a new cover gasket Assembly sequence is the reverse of the dis assembly procedure C COVER BOLT Nds LOCKING C E FIGURE 20 WATER PUMP CLEARANCES Centering Pump Body After the pump has been assembled see Figure 20 the impeller B must be centered in the body cover space C C Adjustment is made by moving the pump body fore and aft u
15. This means most particles escaping the first filter are trapped in the second filter MANIFOLD INJECTION NOZZLE CONNECTION POINT FOR FUEL RETURN LINE SEDIMENT QT BOWL INJECTION PUMP SECONDARY PRIMARY FUEL FILTER FUEL FILTER AIR MANIFOLD CLEANER HEATER INJECTION g INJECTION NOZZLE NOZZLE cy i GLOW PLUG GLOW PLUG CRANKCASE BREATHER TUBE CONNECTION POINT FOR FUEL RETURN FUEL TRANSFER LINE PUMP m PRIMARY FUEL FILTER INJECTION PUMP f FUEL FROM SECONDARY TANK FUEL FILTER FIGURE 29 FUEL SYSTEM OLDER MODELS FUEL TRANSFER PUMP The fuel transfer pump Figure 30 is a diaphragm and check valve type pump operated by a cam lobe on the engine camshaft The pump cam follower has a wide surface to prevent wear as it rides on the camshaft lobe The priming lever is manually oper ated to prime and bleed the system The diaphragm spring maintains required fuel pres sure to the injection pump Fuel pressure should be as follows when operating at 1800 rpm E 5 to 6 psi 34 5 to 41 4 kPa MDJB eee 12 to 14 psi 83 to 97 kPa 12 to 14 psi 83 to 97 kPa Priorto 1962 and October through December 1964 2 to3 psi 14 to 21 kPa Prior to 1962 2 to 3 psi 14 to 21 kPa ak 31 ROCKER ARM SPRING COVER DIAPHRAGM ASSEMBLY an zy DIAPHRAGM SPRING ROCKER ARM PIN
16. adjust pinion gap 1 Remove M terminal nut and wire from solenoid 2 Connect positive terminal of battery to S termi nal on solenoid and negative terminal to starter body With battery connected pinion gear will STOP RING shift into the cranking position OVERRUNNING CLUTCH 3 Gently push pinion shaft back towards front STOP RING bracket and measure the amount of travel Figure 98 PINION SNAP RING OF TRAVEL l d PINION GAP FIGURE 96 PINION GEAR INSTALLATION ES 1192 FIGURE 98 PINION GAP ADJUSTMENT 4 The pinion gap should be 0 3 to 2 0 mm 0 018 to 0 0787 inch Adjust by changing the number of Lever Assembly Installation fiber washers used on solenoid mounting sur Figure 97 shows the correct method of installing the face increasing the number of fiber washers lever assembly spring and packing Note direction decreases clearance Decreasing the number of of lever washers increases clearance n BELT DRIVEN 35 AMP BATTERY CHARGING ALTERNATOR Optional This information is presented for field use only Major repair should be done in the shop Brush Assembly Removal Remove brushes as follows 1 Remove three screws which fasten voltage regu lator to aiternator 2 Disconnectregulator leads and remove regulator 3 Remove two screws on phenolic cover and lift out cover and gasket 4 Pull brush assembly straight up and lift out 5 Reverse proc
17. cam lobes on the camshaft in a vertical posi tion so the base circle of each lobe faces the adapter opening 54 B Using a depth micrometer measure the dis tance from the mounting face of the adapter to the base circle of either cam lobe The shim kit contains shims in the following thicknesses 0 002 0 003 0 006 0 010 0 014 and 0 018 inches If one shim is not enough the required shim thickness between 0 004 and 0 020 can be obtained within 0 001 inch by combining two of the above shims The thickness in inches is stamped on each shim For the greatest accu racy measure the total shim thickness with a micrometer 4 To calculate the shim thickness determine the following Standard installation depth of pump is 3 2598 inches 82 8 mm Distance from adapter flange to cam lobe base circle as measured subtract from above Required shim thickness inches mm Many earlier spec AB MDJE engines have an instal lation dimension of 3 2540 inch 82 652 mm On these units a silkscreen print indicates this dimen sion If so 3 2540 should be substituted for 3 2598 in Step 4 INJECTION PUMP INSTALLATION Install injection pump on adapter assembly as follows 1 Rotate crankshaft to position camshaft so that the pump rollers contact the camshaft base circle low point of the pump cam lobes One lobe should be up the other lobe down See Figure 63 2 Using proper shim thickness Figure
18. or pitting and replace if any of these conditions exist Replace any other worn components such as bearings seals or impeller and use a new impeller housing gasket 1 Install the new slinger on the water pump shaft 2 Install the ceramic part of the two piece seal assembly in the pump housing The rubber side of the seal should be toward the bearings 3 Coat the inside of the water pump housing and the outside of the ball bearing races with grease 4 Insert the water pump shaft into the pump hous ing and install the internal retaining ring in the drive pulley end of the housing 5 Install the spring portion of the two piece seal on the pump shaft and secure in place with the external retaining ring 6 Install the wear plate sothatthe notch in the plate fits into the machining in the pump housing 7 Coat the inside of the impeller housing with grease 8 Install the impeller in the impeller housing by twisting it clockwise while pushing it into place 9 While holding the gasket in place against the pump housing install the impeller housing secur ing it with four screws removed during disas sembly Mount the pump on the engine and attach the hoses Align the pump drive pulley with the crankshaft drive pulley and tighten the set screw 10 11 28 SEAL SEAT S KEY c IMPELLER e GASKET 089 SHAFT 2 BUSHING END PLATE a 7 a SEAL AND SPRING 2 ASSEMBLY 7 SNAP
19. 0 002 inch 0 005 inch 0 010 inch and 0 025 inch 0 051 0 127 0 254 and 0 635 mm Otherwise install new stand ard size seat inserts Drive the new valve seat inserts into place Be certain that each seat rests solidly on the bottom of the coun terbore atall points To make installation easier heat the cylinder head in an oven at 325 F 162 C for about 1 2 hour and cool the valve seats in dry ice Face each new seat to a 45 degree angle and a width of approximately 3 64 inch 1 191 mm The finished seat face should contact the approximate center of the valve face Use Prussion Blue on each valve face to check this Make any corrections on the seat not the valve face When the new seats are installed and faced insert the valve into each and check the clearance from the valve head to the face of the cylinder head This must be atleast0 025 inch 0 64 mm If itis not regrind the seat 18 Valve Springs Check the valve springs on an accu rate compression scale Valve spring data is given in the DIMENSIONS AND CLEARANCES section Replace any spring that is weak cracked or pitted or that has ends out of square VALVE AND HEAD ASSEMBLY Use the following procedure on all J Series engines and generator sets regardless of which valve stem oil seal is used Apply SAE 50 engine oil to valve stem oil seals before installing valve valves and valve stems 1 Support valve stem seal when installing valves Spring retai
20. 1 D fuel with a minimum Cetane number of 45 Number 2 diesel fuel gives the best economy for most operating conditions however use ASTM 1 D fuel during the following conditions 1 When ambient temperatures are below 32 F 0 C 2 During long periods of light engine load or no load NOTE Fuels with Cetane numbers higher than 45 may be needed in higher altitudes or when extremely low ambient temperatures are encountered to prevent misfires Use low sulfur content fuel having a pour point ability to filter of at least 10 F below the lowest expected temperature Keep the fuel clean and pro tected from adverse weather Leave some room for expansion when filling the fuel tank Due to the precise tolerances of die sel injection systems it is extremely important the fuel be kept clean Dirt in the system can cause severe damage fo both the injection pump and the injection nozzles WORK TRANSFER PUMP PRIMING LEVER UNTIL FUEL FLOWS FROM RETURN LINE FITTING OF INJECTION PUMP FIGURE 1 BLEED FUEL SYSTEM if the camshaft pump lobe is up crank engine one revolution to permit hand priming When finished return priming lever inward disengaged position to permit normal pump operation Bleeding Fuel System Bleed air from fuel system as follows Disconnect fuel return line Figure 1 Operate hand priming lever on fuel transfer pump until fuel flowing from fuel return line is free of air bubbles Then reconnect the fu
21. 105 shows the decompression release in detail The release must operate properly for depen dable engine starting and stopping 1 With the piston 10 to 45 degrees past TDC on the power stroke hold the arm in the decompression position tension against spring Turn the set screw so it just touches the exhaust rocker arm The release arm must be tight against the snap ring during adjustment Then turn the screw exactly one revolution clockwise The original factory setting is marked with white or yellow paint DECOMPRESSION END OF SPRING SPRING BEHIND STOP Ox SOLENOID Jh DECOMPRESSION SOLENOID PLUNGER RELEASED IN STOPPED POSITION ATOS Rev DECOMPRESSION RELEASE ARM IN RUNNING POSITION DECOMPRESS ON RELEASE ARM EXHAUST VALVE ROCKER ARM LOCK NUT DECOMPRESSION RELEASE ARM AND SET SCREW IN STOPPED POSITION EXHAUST f ROCKER ARM BROKEN LINE INDICATES MOVEMENT WHEN UNLOCKED FIGURE 105 DECOMPRESSION RE EASE NOTE If the screw is tightened more than one turn the exhaust valve coutd hit the piston Hold the set screw and lock it into position with the attached nut Turn the nut finger tight plus 1 4 to 1 2 turn to lock the mechanism 2 Release the mechanism to allow compression Check the clearance between the screw and rocker arm insert a feeler gauge between valve and rocker arm to take up valve clearance for this check If there is no
22. At the same time con tacts in the solenoid close to provide a circuit for the starter motor The starting motor remains engaged until the starting switch is released If engine is equipped with a start disconnect switch the starter motor will automatically disengage fiywheel gear when engine speed reaches about 900 rpm The starter is protected from over speed by an over running clutch which permits the engine to run faster than the starter before the pinion is disengaged Fig ure 86 shows the starting circuit MAINTENANCE Periodically check the starting circuit wiring for loose or dirty connections Inspect the starter commutator and if it is dirty clean with number 00 sandpaper do not use emery cloth or emery paper Check the brushes for poor seating on the commutator and for excessive wear TESTING Poor cranking performance can be caused by a faulty starting motor defective battery or high resistance in the starting circuit Check the charge condition of the battery with a hydrometer ignition of explosive battery gases WARNING mighi cause severe personal injury Do not smoke while servicing batteries Specific gravity should be between 1 290 and 1 225 when 75 percent charged If not recharge the battery Check electrolyte level If battery will not recharge replace it Keep battery connections tight and clean With the starting motor operating check the voltage drops 1 from the battery ground
23. Each cast iron cylinder head assembly has alloy hardened faced valves release type rotators alloy hardened inserts guides rocker arms injection noz zles and glow plugs The push rods run through shields Keep rocker arms rocker arm nuts push rods and tappets in order so they go back in the same valve train position 1 Remove rocker box cover fuel nozzles and con necting oil lines to cylinder heads 2 Remove intake and exhaust manifold 3 Remove capscrews holding each cylinder head to cylinder block 4 Remove each head If it sticks rap it sharply with a soft hammer Do not use a pry 5 Remove rocker arms and push rods 6 Using a valve spring compressor disassemble the valve assemblies Repair Thoroughly clean ail components of the cylinder head assemblies Remove ali the carbon deposits from the intake and exhaust ports and clean all gasket surfaces Valves Remove all carbon and check each valve for burning pitting or a warped stem Refinish valves that are slightly pitted or burned Use an accurate valve grinder Refinish intake valves to a 42 degree angle and exhaust valves to a 45 degree angle If they are badly pitted or have a thin edge when refacing replace them Check refinished valves for a tight seal to the valve seat with an air pressure type testing tool or by ap plying Prussion Blue to the valve face and rotating it against the seat Valve Guides Check valve guide to valve clearance
24. Figure 55 on side of injection pump Rotate drive gear until a 0 125 inch 3 175 mm brass rod can be inserted into drive gear slot This locks the gear in position when installing injection pump on engine ROTATE GEAR UNTIL BRASS ROD SLIPS INTO PLACE LOCKING GEAR INSERT BRASS ROD FIGURE 55 LOCKING THE DRIVE GEAR 30 3 With injection pump drive gear locked place pump in mounting hole Hold pump firmly against cylinder block A slight spring pressure indicates that the pump and camshaft gears are meshed Figure 56 J PUMP Ww MOUNTING ENGINE FLANGE BLOCK SHIMS 1 171 INCH INSTALLED DIMENSION FACE GEAR PUMP TAPPET li Til ENGINE CAMSHAFT DRIVE GEAR MULTI LOBE CAM FIGURE 56 PUMP INSTALLED 4 If gears mesh secure pump using a fiat washer lock washer and nut on each stud Torque nuts evenly to 15 to 16 ft Ib 20 to 22 Nm 5 Remove brass rod and install timing hole washer and screw BRYCE KIKI FUEL SYSTEM The Bryce or Kiki fuel injection system Figure 57 is located near the center on the left side of the engine crankcase on MDJE engines The pump is mounted on an adapter casting Two lobes of the cam shaft operate the pump plungers one plunger and cam lobe for each cylinder The fuel is pumped at high pressure by the plungers through the delivery valves to the injection nozzles The Bryce Kiki injection pumps operate on the same pumping and me
25. PC point of each fuel injection cycle The PC point should be about the same for each cylinder but an allowable difference between cylinders is 2 5 crankshaft de grees of rotation measured on the flywheel rim Approximately 0 1 inch 2 54 mm is equivalent to 1 degree of rotation At 1500 and 1800 rpm PC should 55 occur at 18 x 4 MDJE engines If piston drop is measured to determine the PC point the nom inal value is 0 115 inch 2 9 mm the allowable range is 0 171 to 0 070 inch 4 3 to 1 8 mm DELIVERY PIPE DELIVERY VALVE HOLDER DELIVERY VALVE SPRING DELIVERY VALVE PUMP HOUSING SUCTION CHAMBER CONTROL RACK PLUNGER UPPER SPRING PORT PLUNGER BARREL KNOCK PIN SEAT CONTROL SL EVE PLUNGER SPRING LOWER SPRING SEAT SNAP RING TAPPET GUIDE PIN FIGURE 65a SINGLE INJECTION PUMP ASSEMBLY Flow Timing Procedure To determine PC proceed as follows 1 Remove one high pressure line both ends and the corresponding delivery valve holder spring volume reducer and delivery valve Figure 65a Leave gasket and seat in pump Place the spring and volume reducer in a clean container of fuel until re installed 2 Re install delivery valve holder without spring and volume reducer 3 Install high pressure line on delivery valve outlet so that drops of fuel can be easily counted and collected in a receptacle at the open end of the line 4 Move the fuel control arm towa
26. RING SNAP RING 7 SLINGER BODY BEARING FIGURE 23 PUMP 4132 0115 WATER PUMP 4132 0115 Water pump 11132 0115 is a neoprene impeller type pump see Figure 23 An alternate pump was occa sionally used for part number 132 0115 Refer to the rebuild procedures for pump 4132 0146 if the pump being serviced does not match the pump shown in Figure 23 Disassembly 1 Remove the pump end plate screws and lock washers end plate and gasket 2 Pull out neoprene impeller with a pair of pliers being careful not to damage the pump body 3 If further disassembly is necessary disconnect the hoses and remove the two cap screws holding the pump to the engine Lift pump from engine 4 Remove the snap ring from the drive end of the pump shaft 5 Remove the shaft assembly by tapping lightly on the drive end of the shaft Use a brass or wood dowel to avoid damaging the shaft 6 Slide the seal and spring assembly off the drive end of the shaft 29 7 Insert the drive end of the shaft into the impeller end of the pump Guide the shaft through the seal until the shaft shoulders against the bearing Tap lightly on the shaft with a brass or wood dowel until the bearing is out Also remove the oil slinger or O ring 8 Insert the impeller end of the shaft into the engine end of the pump and guide it through until the snap ring shoulders against the seal seat Tap lightly on the shaft until the seal seat is out 9 The graphite bu
27. SECONDS ENGAGE FUEL SOLENOID SWITCH IF SO EQUIPPED ENGAGE START SWITCH WHILE CONTINUING PREHEAT IF ENGINE FIRES BUT DOES NOT START REPEAT ABOVEPROCEDURES INCLUDING PREHEAT LIMIT CRANKING TO 15 TO 20 SECONDS TO CONSERVE BATTERY IF ENGINE STILL DOES NOT START SEE IF ENGINE FAILS TO START INFORMATION GLOW PLUG INJECTION PUMP T FUEL FILTERS IF ENGINE FAILS TO START IMPORTANT KEEP ENTIRE FUEL SYSTEM CLEAN AND FREE FROM WATER DIESEL INJECTION PUMPS WILL FAIL IF SYSTEM CLEANLINESS IS NEGLECTED INJECTION PUMPS AND NOZZLES ARE NOT FIELD REPAIRABLE WHEN TROUBLESHOOTING CHECK ALL OTHER COMPONENTS FIRST TEMPERATURES BELOW 32 F 0 USE NUMBER 1 DIESEL FUEL USE CORRECT VISCOSITY OIL KEEP BATTERIES FULLY CHARGED DO NOT USE ETHER STARTING AID d 7 BLUE WHITE EXHAUST SMOKE ENGINE IS GETTING FUEL CHECK PREHEAT SYSTEM FUEL FLOWS STEADILY CHECK FUEL SOLENOID SOLENOID ROD SHOULD PULL IN AND THROTTLE ARM FOLLOW AS SHOWN WHEN START SWITCH IS TURNED ON IF NOT CHECK FOR BINDING LINKAGE p OR BROKEN WIRES SOLENOID ROD NW THROTTLE ARM IF ENGINE IS STILL NOT GETTING FUEL CHECK TRANSFER PUMP 98 4006 1 CRANK ENGINE AND OBSERVE FUEL FLOW FROM RETURN LINE 2 IF FUEL DOES NOT SPURT OUT PUMP MAY BE DEFECTIVE 1 OBSERVE AIR HEATER THRU AIR INLET 2 ENGAGE PREHEAT IF HEATER ELEMENT DOES NOT GLOW RED WITHIN 30 SECONDS CHECK AIR HEATER AND GLOW PLUG W
28. abnormal remove the pump for replacement or repair Removal Remove the pump inlet and outlet lines Remove the two capscrews holding the pump to the engine and lift it off Do not lose the shims They time the injec tion pump to the engine Cap all openings in the pump and fuel lines to keep dirt out of the fuel system Timing Timing the pump to the engine determines the port closing point 17 degrees BTC PC mark on flywheel See Figure 38 The helix position controls port open ing and is in turn controlled by the throttle setting INJECTION PUMP TIMING FIGURE 38 The most accurate method of injection pump timing is with a depth micrometer Method 1 However if a depth micrometer is not available time it by Flowing the Pump Method 2 Injection pump must be timed on the compression stroke not on the exheust stroke Method 1 Depth Micrometer 1 Install pump tappet in its recess and position fly wheel on the port closing mark PC of the com pression stroke Using a depth micrometer measure the distance from the pump mounting pad on the crankcase to the tappet center See Figure 39 Subtract from the port closing dimension of the pump 1 670 inch 42 42 mm the depth obtained in step 2 The result is the thickness of shims necessary to time the pump correctly Thickness of shims may vary from 0 006 to 0 052 inch 0 15 to 1 82 mm If it does not fali within these limits check camshaft an
29. actual port closing found in Step 7 C Multiply distance measured times 003 inch 0 76 mm to determine the difference in thickness required for new button One degree of crankshaft rotation equals the 0 1 inch graduation or 003 inch button thickness for timing Example 1 The port closing time is ate by 0 3 inch 7 6 mm measurement 3 x 003 009 3 x 076 229 mm Since 0 1 inch 2 54 mm equals 003 inch 076 mm in button thickness the installed button is too thin by 009 inch 0 229 mm This means a button 009 inch 0 229 mm thicker than the one installed is required to time port closing so that PC mark on flywheel aligns at the timing pointer when fuel flow stops Example 2 PC timing is too early 0 4 inch 10 2 mm multiply 4 x 003 0 12 inch 4 x 076 mm 0 305 mm In this case a button 012 inch 0 305 mm thinner than the one installed is required D After determining which timing button is required remove injection pump and install the correct button Install new injection pump with No 1 injection line connected to injection nozzle Onearly model Figure 50 injection pumps remove capscrew and install valve spring and capscrew with gasket Torque capscrew to 75 to 89 ft Ib 102 120 Nm On late model Figure 49 injection pumps remove delivery valve capnut and holder to install spring Before installing delivery valve spring push delivery valve back onto its seat usi
30. ance seiting for your particular engine Adjust valve lash after 50 hours of operation following engine overhaul EXHAUST VALVES FIGURE 100 CHECKING VALVE CLEARANCES 2 To adjust valve clearance on four cylinder J Ser ies engine proceed as follows A Adjust valve clearance in firing order 1 2 4 3 sequence After the cooling period adjust number 1 cylinder according to Steps 1A and 1B Aftertiming the number 1 cylinder adjust valve clearance according to Steps 1C MEASURE VALVE ADJUST ROCKER CLEARANCE HERE NUT oo ARM VALVE SPRING INTAKE VALVE FIGURE 101 SETTING VALVE CLEARANCE B To adjust valve clearance for number 2 cylinder turn flywheel in a clockwise direc tion 180 degrees 1 2 revolution from posi tion used in Step 2A The flywheel position should be between 10 degrees and 45 degrees past the bottom center BC IMPORTANT Four cylinder engines do not have a BC mark on the flywheel C After timing number 2 cylinder adjust valve clearance according to Step 1C D To adjust valve clearance for the number 4 cylinder turn flywheel in a clockwise direc tion 180 degrees 1 2 revolution The fly wheel should be between 10 degrees and 45 degrees past flywheel TC mark E After timing number 4 cylinder adjust valve clearance according to Step 1C F To adjust valve clearance for the number 3 cylinder turn flywheel in a clockwise direc tion 180 degrees 1 2 revolution The fly
31. at the intake manifold and a glow plug in each cylinder that heats the precombustion chamber for engine starting Figure 71 The manifold heater and glow plugs are wired in parallel and are controlled by a preheat switch on the control box FIGURE 71 GLOW PLUG AND MANIFOLD HEATER Slightly open pilot spray Fully open main spray FIGURE 69 NOZZLE SPRAY ACTION Governor System The purpose of the engine governor is to maintain a constant engine speed during changes in power demands A governor responds to changes in power demands by varying the throttle position A constant speed governor is standard on marine engines GOVERNORS The constant speed governor maintains engine speed up to 2400 rpm The speed sensing device is a ball and cup mechanism on the camshaft gear A yoke resting on the cup is connected to the throttle lever Any change in engine speed is transmitted from the cup to the yoke and on to the throttle Tension on the governor spring determines the speed at which the engine is controlled A stud screwed into the spring is used to vary the number of effective coils for getting the desired sensitivity the speed drop from no load to full load Maintenance Periodically lubricate the metal governorlinkage with lubricating graphite or light non gumming oil Also inspectthe governor linkage for binding or excessive slack or wear Plastic ball joint socket does not need lubrication Adjustments M
32. camshaft center pin extends out 3 4 inch 19 mm from the end of the camshaft This distance provides an in and out travel distance of 7 32 inch THIS SURFACE MUST 5 6 mm forthe governor cup as illsutrated Hold the BE CLEAN BEFORE cup against the flyballs when measuring The cam SEAL shaft center pin cannot be pulled outward or removed without damage If the center pin extends out too far the cup will not hold the flyballs properly If the dis FIGURE 107 GEAR COVER OIL SEAL tance is less than 7 32 inch 5 6 mm the engine will race especially at no load remove the center pin and press in a new pin installation To instal the governor assembly tip the front of the unit upward Set the flybalis in their recesses and position the governor cup on its shaft Finally brush with heavy grease and instali the snap ring on the center pin PISTONS RINGS CONNECTING RODS DJengines use cam ground aluminum pistons Each piston is tapered and fitted with three compression rings and an oil control ring Full floating piston pins connect the piston to its connecting rod The pins are held in place with a snap ring at each end The lower end of each connecting rod contains half shell preci sion bearings the upper end semi finished bushings GOVERNOR CUP GOVERNOR FLY BALL Some engines are fitted with 0 005 inch 0 127 mm oversize pis tons at the factory These engines are marked with an E following theen
33. debris and cleaned if necessary The water inlet should not be directly in line with other water inlets as this could reduce the amount of water received by the unit when the boat is underway If more than one inlet is present they should be staggered 20 RECOMMENDED FLUSH TYPE THRU HULL FITTING AND WATER FILLER TO ELECTRIC PLANT WATER FILTER 5 FLUSH THRU HULL FITTING STRAINER WARNING DO NOT USE SCOOP TYPE WATER INLET FITTINGS ON ELECTRIC PLANTS USING AQUALIFT MUFFLER SYSTEMS FIGURE 12 TYPICAL MARINE WATER FILTER Do not use a scoop type water inlet fitting When the boat is underway and the generator set is not running sufficient ram pressure can force water past the sea water pump flooding the exhaust system and possibly flooding the engine cylinders Before starting operation the sea water pump should be primed and checked for water flow The pump is primed by removing a priming plug on the top of the pump not necessary with metal impeller pumps or by removing the outlet hose from the pump con nection Fill the pump and hose with water and replace the components With the set running check the exhaust outlet to verify that the pump is delivering water An insufficient flow of water indicates that there are obstructions in the system the water pump belt is loose or the water pump is faulty Inspect and replace any hoses or pipes that have become re stricted or blocked Refer to the section on Wa
34. fill the pump intake and outlet with oil to be sure it is primed Mount the pump on the engine and adjust the 0 005 inch 0 127 mm lash between the pump gear and crankshaft gear Mount the intake cup on the pump so it is parallel to the bottom of the crankcase 82 BYPASS VALVE Located on the outside of the rear bearing plate the bypass valve Figure 76 controls oil pressure by allowing excess oil to flow directly back to the crank case Normally the valve begins to open at about 25 psi 172 5 kPa It is non adjustable and normally needs no maintenance To determine if high oil pressure is caused by the plunger sticking closed or low oil pressure by the plunger sticking open clean and inspect the valve To remove the valve unscrew the recessed plug in the rear bearing plate and lift out the spring and plunger assembly Determine proper valve operation by checking the spring and plunger against the given values Plunger Diameter 0 3365 inch to 0 3380 inch 8 5471 to 8 5852 mm Spring Free Length 2 5 16 inches 1 16 inch 74 613 1 588 mm 2 225 Ib at 1 3 16 inches compressed 1 01 kg at 30 163 mm compressed CYL HEAD 3 AND 4 AREA See Note 4 CYLINDER ONLY FLUSH ROCKER BOX OIL LINE WITH FUEL AND CLEAN HOLES WITH FINE WIRE CYL HEAD 2 INJECTION PUMP PAD REAR BEARING PLATE OIL BYPASS SPRING OIL BYPASS FIGURE 76 BYPA
35. flush with con necting rod to provide for oil recess in center 2 Install all rings on each piston All compression rings will be marked top or identified in some other manner Place this mark toward closed end of piston Space ring gaps 1 4 of way around piston from one another No gap should be in line with the piston pin 3 Position a bearing half in each connecting rod Be sure there is no dirt under bearing This could cause high spots and early bearing failure 4 Oil cylinder walls Install each piston in proper cylinder using a suitable installer Each assembly should be installed with stamp on piston facing same direction as when removed 5 Position each connecting rod on crankshaft oil the journal and install its rod cap and bearing half When installing rod cap position so raised witness mark on forging matches mark on con necting rod See Figure 111 6 Tighten capscrews to specified torque 7 Crank engine over by hand to see that all bearings are free 8 Install oil base with a new gasket 9 Install cylinder heads using proper bolt tighten ing sequence 10 Replace oil CAMSHAFT The camshaft is a one piece machine casting driven through gears by the crankshaft It rides on sleeve bearings pressed into the crankcase In addition to providing a means of opening and clos ing the valves the camshaft operates the injection pump and fuel transfer pump SURE THAT CONNECTING ROD WITNESS
36. integral part Assembly Inspect the pump housing for wear rough surfaces or pitting and replace if any of these conditions exist Replace any other worn components such as bear ings seals or impeller and use a new end plate gasket 1 Apply sealing compound to the sealing lip around the edge of the bellows seal Place the bellows seal in the pump body and drive it into place Step g 2 Apply asmall amount of Loctite or equivalent on the outside surface of the bearing Step h 3 Place the bearing and shaft assembly in the pump bore and drive into place Step i Strike outer race only to avoid damage to pump shaft and bearing 4 Lubricate both sides of the seat assembly ce ramic seal and O ring with lubricating oil and slide assembly over pump shaft The ceramic portion of the seat assembly should contact the bellows Compress the seat assembly against the bellows and at the same time push the retaining ring into its groove on the pump shaft 5 Place wear plate and cam so notch in wear plate lines up with tang on cam Step j Fasten cam to housing with screw 6 Align the flat spot in the center of the impeller with the flat spot on the pump shaft Bend back the impeller blades nearest the cam and push the impeller onto the shaft Do not remove the factory coating of oil from the new impeller before installing BEARING AND SHAFT ASSEMBLY BELLOWS SEAT ASSEMBLY ASSEMBLY CAM wa SCREW RETAINING RING
37. leaks internal pump timing and calibration and adjustment to the manufacturer s specifications MDJA INJECTION PUMP INJECTION LINE CAP NUT VALVE HOLDER VALVE SPRING VALVE ASSEMBLY PUMP HOUSING GASKET GASKET FONT LOCATING SCREW LEVER BY PLUNGER BARREL 7 CONTROL SLEEVE mE CLOSING PLUG SHAFT ASSEMBLY UPPER SPRING SEAT PLUNGER SPRING PLUNGER RETAINING RING LOWER SPRING SEAT FIGURE 37 PLB INJECTION PUMP COMPONENTS 42 A PLB injection pump Figure 37 is used on the MDJA Series engines The cross sectional view shows the internal parts and the operating lever and control shaft The pump consists of a housing pump plunger and barrel the plunger return spring with its seats and the control sleeve and its operting shaft The housing contains the fuel sump delivery valve assembly delivery valve holder and the union nut for connec tion of the high pressure discharge tubing Repair Most fuel system troubles are not due to a faulty injection pump Testthe rest of the fuel system before condemning the injection pump Onan discourages field repair of the injection pump because of the exceptionally close tolerances be tween parts and the specialized equipment necessary for repair The injection pump is an expensive part of the unit and even a particle of dirt as fine as talcum powder could score its working surfaces If the rest of the fuel system is in working order and fuel delivery is
38. on the camshaft rides on atappet assembly in the pump and drives the plunger up and down OPERATING 6 LEVER PSU PUMP PUMP MOUNTING FLANGE FACE GEAR AAA ENGINE CAMSHAFT R MULTI LOBE DRNEGEA CAM FIGURE 43 INJECTION PUMP TO CAMSHAFT RELATIONSHIP CAP NUT HYDRAULIC HEAD T e LEVER as te ilz HYDRAULIC Em O RING f 1 UE TAPPET FIGURE 44 Pump Cutaway View The cutaway view in Figure 44 shows the control unit operating lever metering sleeve delivery valve plunger and drilled passages to the plunger and injection lines A timing button of very precise thickness transmits motion from the tappet to the plunger and adjusts plunger timing for the fuel pumped to each injector during operation Plunger reciprocation and rotation are phased so that only one fuel injector is served during the affective portion of each plunger up stroke The high hydraulic pressure developed is required to open the pressure operated fuel injector nozzles which inject the fuel in a fine mist into the combustion chamber Fuel delivery control ful load and shutoff are regulated by the up and down move ment of the fuel metering sleeve The sleeve is con trolled by the operating lever on the outside of the pump Fuel is injected only during the high velocity portion of each plunger up stroke When the tappet slips off each lobe of the camshaft the spring load
39. outputto protect the engine from excessive loading Do not change the adjustment of this device unless absolutely re quired The warranty may be voided if the fuel stop is intentionally altered to increase engine power above 10 percent overload at rated speed and load FUEL CONTROL ARM ADAPTER FIGURE 60 ADAPTER ASSEMBLY SHAFT POSITION OF FLAT FOR REMOVING AND INSTALLING PUMP TO ADAPTER TOP END 15 OVERLOAD FUEL PLUNGER ADAPTER ADJUSTED AT FACTORY BOSS DO NOT CHANGE EXTERNAL RETAINING RING SHAFT AND YOKE ASSEMBLY LOCK NUT GUIDE ADAPTER DOWEL PIN HOLES 2 DOWEL PIN ADAPTER MOUNTING HOLE BOLT HOLES 4 BRYCE ONLY PUMP MOUNTING HOLES 4 FIGURE 61 INJECTION PUMP ADAPTER ASSEMBLY A diesel engine cannot tolerate dirt in the fuel system Dirt is one of the major causes of diesel engine failure A tiny piece of dirt in the injection system may stop your unit When opening any part of the fuel system beyond the secondary fuel filter place all parts in a pan of clean diesel fuel as they are removed Before installing new orused parts flush them thoroughly and install while still wet Removal 1 Remove fuel control arm 2 Remove four mounting bolts and lift adapter assembly off of engine block It may be necessary to tap assembly with lead or plastic hammer in order to loosen adapter from gasket 3 Discard old gasket and clean area on engine block
40. positioned the same way they were when removed Captive Water Side The captive water side of the heat exchanger should be protected from corrosion and scale formation by filling the engine cooling system with a50 50 mixture of antifreeze and water not protected rust and scale will form on the walls ofthe engine water jacket The rust and scale will combine to form an insulation layer on the water jacket which will reduce the efficiency of heat transfer to coolant This can lead to overheating and subsequent damage to the engine Rusty water or rusty solutions of antifreeze indicate the formation of rust on the water jacket If this is the case the engine water jacket and heat exchanger should be cleaned and thoroughly flushed out as described in the MAINTENANCE section Use a chemical cleaner to remove rust and scale deposits following the procedure recommended by the sup plier REASONATOR ENGINE GENERATOR DUAL FUEL FILTERS KEEL COOLERS Keel cooling see Figure 17 is available as an option on the MDJA MDJB MDJC MDJE and MDJF generator sets The captive water pump mounting bracket belt guard hose and fittings are supplied by Onan Some sets may also have a sea water pump for injecting water into the exhaust system while other sets may use a dry stack exhaust The keel cooler expansion tank and plumbing must be supplied by customer The keel cooler should be protected from corrosion and sca
41. terminal post not the cable clamp to the cylinder block 2 from the cylinder block to the starting motor frame and 3 from the battery positive post to the battery terminal stud on the solenoid Normally the voltage drops at 1 and 3 should never exceed 0 6 V each even under the most severe conditions extreme cold The voltage drop at 2 should never be permitted to exceed 0 3 V under the same severe conditions Tho roughly clean all connections in any part of the circuit showing excesively high voltage drops If starting motortests are required remove the motor from the engine and test it on a bench Test the free running voltage and current TO START SOLENOID GROUND CONNECTION TO ENGINE BATTERY A712 FIGURE 86 STARTING SYSTEM Using a spring scale and torque arm test the stall torque Figure 87 Multiply the spring scale reading by the arm length for the torque valve If free running speed is low and starter has a high current draw with low stail torque check for tight dirty or worn bushings bent armature shaft or loose field pole screws allowing armature to drag Check also for shorted or grounded armature and field A low free speed with low torque and low current draw indicates an open field winding high internal resistance due to poor connections defective leads broken or worn brushes or scored worn or dirty commutator KNIFE SWITCH SCALE GROUND ON OTOR AT POINT OF
42. to the heat exchanger 1 Remove fili cap 2 Open fill vent valve turn counterclockwise 3 Remove vent plug older city water cooled units only 4 Fill with coolant until vents begin to overflow Close fill vent valve turn clockwise 6 Replace vent plug older city water cooled units only 7 Replace fill cap prime pump on marine units 8 Operate unit 10 minutes at full load watch for leaks 9 Shut down unit waRNING Contact with hot coolant might result in serious burns Do noi bleed hot pressurized coolant from a closed cooling system 10 Slowly open pressure cap and check water level 11 Fill system to top with coolant WATER MANIFOLD FILL VENT VALVE HEAT EXCHANGER FIGURE 7 HEAT EXCHANGER FILLING MARINE COOLING SYSTEMS Threetypes of marine cooling systems are in general use today direct sea water cooling heat exchanger cooling and keel or skin cooling Direct sea water cooling systems use an engine mounted pump to draw flotation water and pump it through the engine and out through the exhaust sys tem The floatation or sea water comes in direct con tact with the engine water jacket SHELL tyBEs END COVER ii OUTLET 1 FORWATER IN CLOSED SYSTEM INLET FOR COOLING WATER B258 FIGURE 8 HEAT EXCHANGER FLUSH TYPE THRU HULL FITTING The heat exchanger and keel cooling systems were developed to keep sea water and the resu
43. 00 see Note 1 200 e Check start disconnect circuit Check valve clearances Change primary fuel filter Grind valves if required Clean holes in rocker box see Note 2 3000 Change secondary fuel filter General overhaul if required see Note 3 NOTE 1 Water or foreign material in fuel can ruin the injection system daily inspection shows water or excessive ary and secondary fuel filters must be replaced follow ing correction of fuel contamination problem 2 Thisservice must be conducted by trained diesel injec tion equipment personnel with suitable test facilities Omit this service unti these conditions can be met Replace oil filter Check battery condition oil line orifices dirt in sediment bowl fuel handling and storing facili 3 Tighten head bolts and adjust valve clearance after first om Clean breather standpipes Check nozzle spray pattern ties should be checked and situation corrected Prim 50 hours on an overhauled engine OIL FILTER CHANGE Place pan under old filter and remove by turning counterclockwise Clean filter mounting area Lubri cate gasket on new filter with oil and screw filter on clockwise until gasket touches mounting base then tighten 1 2 turn Crankcase pressure could blow out hot oil and cause serious burns Do NOT check oil while the engine is operating CAP AND OIL LEVEL INDICATOR KEEP CRANKCASE NEVER OPERATE ENGINE WITH OIL BELOW T
44. 11 14 Cylinder head bolt 44 46 60 62 Exhaust manifold nuts 13 15 18 20 Flywheel mounting screw 65 70 88 95 Fuel pump mounting screws 15 20 20 27 Gear case cover 18 20 24 27 Glow plug 10 15 18 20 Injection nozzle mounting SCIeWS 20 21 27 28 Injection pump mounting 15 16 20 22 Intake manifold 13 15 18 20 Oil base mounting screws 45 50 61 68 Oil filter Hand tight plus 1 4 to 1 2 turn Oil pump mounting screws 15 20 20 27 Rear bearing plate 40 45 54 61 Rocker arm nut 4 10 5 13 Rocker arm stud 35 40 48 54 Exhaust nuts must be tightened evenly This torque is due to friction between the threads only and locks the nuts in place Use the rocker arm nut to adjust valve lash Engine Troubleshoot ES DIESEL ENGINE TROUBLESHOOTING GUIDE LIQUID OR AIR COOLED Load Connected When Starting Defective Starner Defective Control Circuit Defective Fuet System Wrong Timing Button in Inject on Pump PRE MELEE _tnsufticrent Coolant Overheating Inadequate Air Circulation EOOD Bote weak vane seme High Exhaust Back Pressure Valves Not Seating Properly Worn Cylinder Walls Pistons Rings Sticking Valves Service and Maintenance PRE STA
45. 6 5 Remove the thermostat from the hot water and allow it to cool in the surrounding air The ther mostat should close within a short time 6 If the thermostat sticks or does not operate prop erly replace it with a new one 7 Always install a new gasket when replacing the thermostat Hefer to the appropriate parts catalog for the ther mostat part number 34 MDJA MDJB MDJE FRONT MOUNT HEAT EXCHANGER THERMOSTAT swo MDJA MDJB MDJC MDJE COVER SEA WATER COOLING AND KEEL COOLER MDJC MDJF SIDE MOUNT HEAT EXCHANGER CYLINDER HEAD MDJC MDJF SIDE MOUNT HEAT EXCHANGER S THERMOSTAT Lr GASKET WATER MANIFOLD FIGURE 27 THERMOSTAT LOCATIONS TABLE 6 THERMOSTAT TEST NUMBER TEMP F F MIN STROKE 147 to 154 64 to 68 C 157 to 164 70 to 74 C 140 to 145 60 to 63 C 175 to 182 80 to 84 C 150 360 in 66 C 9 14 mm 184 360 in 85 9 14 mm 165 130 in 74 C 3 30 mm 202 096 in 95 C 2 44 mm MARINE MUFFLERS A marine muffler is used to silence the generator set Some mufflers have an integral water injection inlet while others are cooled by water through the exhaust line Placement of the muffler in the exhaust line depends on the type of muffler used Usually some tailpipe is left to improve silencing Refer to the manufacturer s installation inst
46. 6 Remove nozzle from tester and holder test stand be sure that fittings match properly YANMAR AMERICAN BOSCH NOZZLE 4 Test nozzle for jamming ADJUSTMENT If the opening pressure is incorrect connect nozzle to tester and hold nozzle in a suitable holder or smooth jaw vise Rt A Bypass pressure gauge B Press nozzle tester hand lever down quickly So that nozzle opens 6 to 8 times per second P p one 1 Remove plug from cap nut Figure 68 C Nozzle should chatter with a shrill whistling sound if valve moves properly Loosen locknut Turn adjusting screw to desired opening pressure WARNING Fuel penetration of the skin might cause severe personal injury Do not let the nozzle high pressure fuel spray against skin surfaces 2 3 4 Tighten cap nut to 45 to 50 ft Ib 61 to 68 Nm 5 install plug using a thread sealant 6 Remove nozzle from tester and holder 98 OPENING PRESSURE The correct opening pressure should be 2100 2200 psi 14480 15169 kPa for new nozzles may be about 200 psi 1380 kPa less after the nozzles have operated a few hundred hours Open pressure gauge to obtain reading Leakage Test 1 Slowly depress hand lever until nozzle test gauge indicates 285 psi 1966 kPa below specified opening pressure 2 Consider nozzle leak proof if no fuel not even one drop emerges from nozzle tip within 10 seconds Chatter Test 1 Operate hand lever downward 1 or 2 nozz
47. 64 install pump to adapter with four socket head capscrews and lockwashers Torque to 20 to 24 ft Ib 27 to 33 Nm Be sure the control rack ball fits between the yoke fingers for proper operation If the rack ball is not properly placed in the yoke engine operation will be uncontrollable and must be stopped immediately such as emergency the engine can be stopped by blocking the air intake or by loosening just cracking the fuel injector line fittings atthe pump end 3 Connect flexible fuel inlet line to pump inlet 4 Connect each high pressure fuel line to proper pump outlet and nozzle inlet Torque nuts to 16 to 18 ft Ib 22 to 24 Nm 5 Reinstall fuel control arm on yoke and shaft assembly Figure 64 Tighten socket head screw but do not over tighten FUEL CONTROL ARM FIGURE 64 PUMP AND ADAPTER ASSEMBLY 6 Adjust fuel solenoid plunger so that a 0 010 to 0 030 inch 0 25 to 0 76 mm clearance exists see 65 between the plunger adjustment screw and the fuel control arm with the solenoid in de energized position To adjust the plunger length hold the plunger and adjust the screw on the plunger lever pin at the fuel shutoff position Retighten locknut FUEL CONTROL POST SCREW CLEARANCE 0 010 0 030 INCH 0 25 0 76 mm FIGURE 65 FUEL SOLENOID ADJUSTMENT Flow Timing Troubleshooting Only Flow timing is performed at either injection line to establish or confirm the port closing
48. DJB MDJC MDJE and MDJF Prior to Spec R both the governed speed and the governor sensitivity are adjusted with the stud and nut on the front of the engine Figure 72 Beginning Spec R the sensitivity is adjusted with an adjusting ratchet Speed Adjustment Prior to Spec R To adjust the governed speed hold the governor spring stud in position and turn the governor spring nut with a wrench For accurate speed adjustment use a reed frequency meter on the AC output A mechanical tachometer is not as accurate On generator set fre quency and speed according to the nameplate Sensitivity Adjustment Prior to Spec R To adjust the sensitivity turn the governor spring stud coun terclockwise gives more sensitivity less speed drop If the governor is too sensitive a hunting condition occurs alternately increasing and decreasing speed Adjust for maximum sensitivity without hunting See the engine nameplate for speed and sensitivity set tings After sensitivity adjustment the speed may require readjustment Speed Adjustment Begin Spec R Adjust engine speed by turning governor speed adjusting nut Fig ure 72 Turn nut clockwise to increase speed coun terclockwise to decrease speed SS TURN TO INCREASE RPM HOLD SPRING STUD IN S POSITION PN te E aw A oo CS K Gir V E L GOYERNOR SPRING TURN FOR MINIMUM GOVERNOR SPEED DROP THEN SPRING STUD ADJUST NUT GOVERNOR SPRING NUT PRIOR TO
49. E ADD DISTANCE ADD MEASURED MEASURED STEP 4 THESE SHIMS THESE SHIMS INJECTION O RING FIGURE 41 SHIMMING THE PILOT With shims and seal in place insert the pump into cylinder block mounting pad and insert mounting screws Torque the mounting screws tighten alter nately to 18 21 ft Ib 24 28 Nm Install the fuel inlet line and governor linkage Bleed the pump and then install the fuel outlet line see INSTALLATION section PSU OR MODEL 50 INJECTION PUMP The PSU or model 50 injection pump Figure 42 is used on Onan2 and 4 cylinder water cooled diesels Pumps that are almost identical with only two injec tor line outlet ports are used on the two cylinder models The function of the pump as a distributor and its location on the service side of the engine are the same on both 2 and 4 cylinder engines Repair Internal repairs on the injection pumps require spe cial tools and step by step procedures for disassem bly and reassembly Replace with a new pump any pump CAUTION that troubleshooting procedures prove to be malfunctioning Do not attempt unautho rized repair procedures on injection pumps FIGURE 42 INJECTION PUMP Pump Operation The pump face gear mates with and is rotated by a drive gear on the engine camshaft Figure 43 The face gear pilot ring and the reciprocating plunger in the pump are rotated continually to assure positive fuel distribution A multi lobed cam
50. FACE LOCK PIN MAIN BEARING MUST BE FLUSH WITH INSIDE SURFACE LIP FACING OUT FIGURE 117 MAIN BEARING INSTALLATION SIDE MARKED FRONT TOWARD CRANKSHAFT GEAR PLACE UPPER BEARING HOUSING HALF IN POSITION INDICATED BY BROKEN LINE ROTATE INTO POSITION E SURE TO ALIGN OIL OLES IN BEARING AND HOUSING FIGURE 118 CENTER MAIN BEARING HOUSING Redistribution or publication of this document by any means is strictly prohibited Redistribution or publication of this document by any means is strictly prohibited Onon Onan Corporation 1400 73rd Avenue N E Minneapolis MN 55432 1 800 888 ONAN 612 574 5000 international Use Telex 275477 Fax 612 574 8087 Onan is a registered trademark of Onan Corporation
51. FIGURE 21 PUMP 131 0152 21 END PLATE WEAR PLATE IMPELLER GASKET IMPELLER HOUSING a RETAINING NG SLINGER kd p PUMP HOUSING BEARINGS AND SHAFT INTERNAL RETAINING RING FIGURE 22 PUMP 131 0257 7 Install the pump end plate using a new gasket and tighten end plate screws to 15 17 inch pounds 1 7 1 9 Nm 8 Install pump on engine Step k and attach hoses WATER PUMP 4131 0257 Water pump 3131 0257 is a neoprene impeller type pump see Figure 22 Disassembly 1 Disconnect all hoses and remove the pump from the engine 2 Loosen the pulley set screw and remove the pul ley from the pump shaft 3 Remove the impeller housing screws impeller housing and gasket 4 Pull the impeller out of the impeller housing 5 Remove the wear plate from the pump housing using a screwdriver to pry the plate loose if necessary 6 Remove the external retaining ring from the impeller end of the water pump shaft 7 Removethe two piece seal assembly The spring portion of the seal is removed first The second portion of the seal can be loosened and removed with a screwdriver or needle nose pliers 8 Remove the internal retaining ring from the drive pulley end of the pump housing 9 Carefully drive out the shaft and bearing assem bly from the impeller end of the housing 10 Remove the slinger from the water pump shaft Assembly Inspect the impeller housing for wear rough sur faces
52. G 8 It is essential that the nozzle body be perfectly 4 Smali holes in tip of nozzle body can be cleaned centered in the cap nut when reassembling noz with afine wire slightly smaller than the size of the zle A centering sleeve as shown is used for this hole purpose FIGURE 35 NOZZLE CLEANING 40 NOZZLE REPAIR If cleaning will not eliminate a nozzle defect replace the nozzle or take it to an authorized diesel service station Do not attempt to replace parts of the nozzle except for nozzle and pintle assembly Assembly Rinse both valve and nozzle thoroughly before assembly and coat with diesel fuel The valve must be free in the nozzle Lift it about 1 3 out of the body It should slide back to its seat without aid when the assembly is held at a 45 degree angle If necessary work the valve into its body with clean mutton tallow Clamp nozzle holder body in a vise Set valve in body and set nozzle over it Install nozzle cap nut loosely Place centering sleeve over nozzle for initial tightening Then remove centering sleeve to pre vent it from binding between nozzle and cap nut 5 Tighten nozzle cap nut to 50 55 ft Ib 68 75 Nm NOZZLE INSTALLATION Before installing the injection nozzles in the engine thoroughly clean each mounting recess A dirty mounting surface could permit blow by caus ing nozzle failure and a resulting power loss 1 Install a new heat shield to head ga
53. ING POINTER 4 X ND f T C TOP CENTER d AB879 5 REAR VIEW FIGURE 52 PORT CLOSING POSITION 6 Manually operate fuel transfer pump Figure 53 until fuel free of air flows from open end of No 1 injection line into container Figure 51 WORK TRANSFER PUMP PRIMING LEVER UNTIL FUEL FLOWS INTO CONTAINER ALWAYS RETURN PRIMER LEVER TO LOWEST POSITION b3U Rev FIGURE 53 OPERATING TRANSFER PUMP MANUALLY 7 Continue operating transfer pump while assistant rotates flywheel slowly in clockwise direction Stop flywheel rotation at exact point that fuel stops flowing from No 1 injection line one drop in 2 to 5 seconds is allowed This point is the injection pump plunger port closing regardless of flywheel position Timing is correct if port closign occurs when PC mark on flywheel aligns with timing pointer Fig ure 52 If the marks do not line up timing is either early or late and the timing button must be changed If Step 7 indicates port closing is incorrect late or early proceed as follows See Examples A Mark flywheel in 0 1 inch 2 54 mm gradua tions about five marks each direction from PC mark for calculating required change in button thickness Figure 54 POINTER EXAMPLE 1 POINTER EXAMPLE 2 Wl All EARLY FLYWHEEL FRONT SIDE FIGURE 54 TIMING MARKS 10 B Measure distance in tenths of an inch or mm from PC mark on flywheel to point of
54. IRING CONNECTIONS TIGHT FREE FROM CORROSION i 8 79 OBSERVE ENGINE EXHAUST SMOKE SIGNALS LITTLE OR NO EXHAUST SMOKE ENGINE IS NOT GETTING FUEL PRIME FUEL SYSTEM OBSERVE FUEL FLOW FROM RETURN LINE LITTLE OR NO FUEL FLOW CHECK FUEL SUPPLY SYSTEM FUEL TANK EMPTY SHUTOFF VALVES CLOSED FUEL LINES KINKED LOOSE CONNECTIONS CLOGGED FUEL FILTERS IF ENGINE STILL DOES NOT START CONTACT AUTHORIZED ONAN SERVICE REPRESENTATIVE AUTOMATIC STARTING AND STOPPING Optional controls may be used for automatic start and stop but must provide engine preheating The automatic control should haveatime delay relay to preheat glow plugs and the manifold heater for at least 20 seconds before cranking occurs The time delay relay prevents immediate engagement of the starter in casethe load is reapplied beforethe engine stops APPLYING LOAD If practicable allow engine to warm up before con necting a heavy load Continuous overloading causes high operating temperatures that can damage the engine The exhaust system may form carbon depos its during operation at light loads apply full load occasionally before shut down to prevent excessive carbon accumulations Try to apply the load in steps instead of full load at one time BREAK IN PROCEDURE The unit should be run in the following sequence 1 One half hour at 1 2 load 2 One half hour at 3 4 load 3 Full loa
55. MARKS ARE O ALIGNED FIGURE 111 CONNECTING ROD CAP Removal 1 Remove rocker arms and push rods from valve chambers 2 Remove injection pump and fuel transfer pump from engine 3 Remove crankshaft gear retaining washer by removing lock ring on crankshaft 4 Lay engine on its side to avoid dropping tappets and remove camshaft assembly as a group If necessary pry it out using a screwdriver between camshaft gear and crankcase 5 Remove valve tappets These can be removed only from the camshaft end of the push rod holes Repair f a lobe has become slightly scored dress it smooth with a fine stone If the camshaft is badly worn or scored replace it After installing a new cam shaft time the injection pump to the engine Never install a new camshaft with old tappets Camshaft Gear This gear is a pressed fit on the cam shaft and drives it at 1 2 the crankshaft speed To remove the gear use a hollow tool or pipe that will fit inside the gear bore and over the center pin Press the camshaft out of the gear bore Be careful notto dam age the center pin Camshaft Bearings The camshaft bearings should bereplaced ifthe clearance to the camshaft is greater than specified the bearings show cracks breaks burrs excessive wear or other defects To check the rear bearing remove the expansion plug atthe rear of the crankcase PRESS BEARING FLUSH WITH EL norroMor Ww RECESS REAR d BEARING CENTER
56. Onon Service Manual MDJB IMIDJIE MDJF Marine Diesel GenSet Engines 974 0750 12 85 Printed in U S A Safety Precautions It is recommended that you read your engine manual and be come thoroughly acquainted with your equipment before you start the engine This symbol is used throughout this manual to warn of possible serious personal injury This symbol refers to possible equip ment damage Fuels electrical equipment batteries exhaust gases and mov ing parts present potential hazards that could result in serious personal injury Take care in following these recommended pro cedures Safety Codes e Ali local state and federal codes should be consulted and complied with e This engine is not designed or intended for use in aircraft Any such use is at the owner s sole risk General e Provide appropriate fire extinguishers and install them in convenient locations Use an extinguisher rated ABC by NFPA Make sure that all fasteners on the engine are secure and accurately torqued Keep guards in position over fans driving belts etc e If itis necessary to make adjustments while the engine is running use extreme caution when close to hot exhausts moving parts etc Protect Against Moving Parts Do not wear loose clothing in the vicinity of moving parts such as PTO shaits flywheels blowers couplings fans belts etc Keep your hands away from moving parts
57. RTING Preparations for the initial and each additional start ing operation should include careful checks ofthe oil fuel cooling and electrical systems Before engine is put in operation check all compo nents for mechanical security If an abnormal condi tion defective part or operating difficulty is detected repair or service as required The engine should be kept free of dust dirt and spilled oil or fuel Be sure proper operating procedure is followed Crankcase Oil Multi grade oils such as 5W 30 are recommended for service in ambient temperatures of 32 F and colder On Onan J Diesel liquid cooled engines SAE 15W 40 or 20W 40 oils CD SE Service Designation may be usedin an ambient temperature range of 15 F 10 C through 90 F 32 C Refer to the oil chart below for recommended viscosity grades at various temperature ambients USE THESE SAE VISCOSITY GRADES 60 20 1 20 TEMPERATURE RANGE YOU EXPECT BEFORE NEXT OIL CHANGE Use oil with an API classification of CD SE all viscos ity grades or CC SE grades 10W 30 10W 40 or 5W 30 only When adding oil between oil changes it is preferable to use the same brand as various brands of oil may not be compatible Refer to Maintenance Schedule for recommended oil change intervals and pro cedures Crankcase pressure could blow out hot oll and cause serious burns Do NOT check oil while the engine is operating Recommended Fuel Use ASTM 2 D or
58. SEAL CAM WEAR PLATE SET SCREW SHAFT IMPELLER PIN BY COVER GASKET IMPELLER FIGURE 25 PUMP 132 0059 WATER PUMP 8182 0059 Water pump 1132 0059 is a neoprene impeller type pump Figure 25 Disassembly 1 Disconnect the hoses and removethe cap screws holding the pump to the engine Lift pump from engine Remove the end cover screws end cover and gasket Pull the impeller and shaft assembly from the pump body Remove the impeller pin and slide the impeller off the shaft Loosen the cam set screw on the side of the pump and tap it lightly to free the cam from the pump body Lift out cam and wear plate Working from the mounting flange end use a small drift punch to drive the seals out toward the impeller Remove the seal next to the impeller bore first Be careful not to damage the bore area around the seal 31 Assembly Inspect the pump housing for wear rough surfaces or pitting and repiace if any of these conditions exist Repiace any other worn components such as seals or impeller Use a new end cover gasket when reas sembling 1 Install the impeller side seal with the seal lip fac ing away from the impeller bore Lubricate the seal lip with grease Install the flange side seal with the seal lip facing away from the mounting flange Lubricate the seal lip with grease Place the wear plate in the bottom of the impeller bore with the raised porti
59. SPEC R GOVERNOR ARM SENSITIVITY ADJUSTING RATCHET BEGIN SPEC R GOVERNOR SPRING GOVERNOR STUD SENSITIVITY ADJUSTING RATCHET DECREASE f SPEED dif INCREASE SPEED INCREASE SENSITIVITY SPEED ADJUSTING DECREASE NUT SENSTIVITY FIGURE 72 GOVERNOR ADJUSTMENTS Sensitivity Adjustment Begin Spec R Adjust sensi tivity no load to full load speed drop by turning the sensitivity adjusting ratchet nut if speed drops too much when a full load is applied turn the ratchet nut counterclockwise An oversensitive adjustment ap proaching no speed drop when load is applied may result in hunting condition alternate increase and decrease in speed MDJA Governor System Adjust engine speed by turning governor speed adjusting nut Figure 73 prior to SPEC R and Figure 74 SPEC R Turn nut clockwise to increase speed counterclockwise to decrease speed Adjust sensitivty no load to full load speed drop by turning the sensitivity adjusting ratchet nut If speed drops too much when full load is applied turn the ratchet nut counterclockwise An oversensitive ad justment approaching no speed drop when load is applied may resuit in a hunting condition alternate increase and decrease in speed Adjust for maxi mum sensitivity without hunting The use of a reed type frequency meter will give the most accurate results On generator sets it should be possible to adjust for a sensitivit
60. SS VALVE AREA See Nore AREA 2 See Note 2 out OIL FILTER ADAPTER FIGURE 77 CLEANING ROCKER BOX OIL LINE AND RESTRICTION ORIFICES 63 Note 1 Use a 70 drill bit 028 in 1 17 for cleaning being careful not to enlarge hole These are restricted flow fittings If holes are enlarged valve deck will receive excess oil If holes are plug ged valvetrain will run dry and wear out Note 2 Use a 56 drill bit for cleaning being careful not to enlarge hole it is critical that fittings be kept open If restriction is plugged injection pump tappet bottom and plunger will wear OIL LINES At overhaul time the rocker box oil line should be flushed with fuel and a fine wire used to clean the small holes Figure 77 Clean standpipe breather on four cylinder engines Clean out all other oil lines and drillings with com pressed air whenever the engine is disassembled or overhauled The oil gauge passage may be reached by removing the oil filter mounting plate External oil lines the rocker box oil line and the internal oil line to the rear bearing are replaceable Restriction orifices are placed in the external oil lines to regulate the quantity of oil delivered to the injec tion pump gearing and tappet and to the rocker arm and valve train areas Two orifices are located in the Tee fitting at the injection pump and one orifice is located in the inlet fitting to each cylinder head To prevent inj
61. THIS LEVEL OIL FILL TUBE OIL LEVEL INDICATOR FUEL PUMP AND FILTER gt BODY BS GASKET FUEL TRANSFER PUMP OIL DRAIN EXTENSION For service convenience install a short less than 10 inches 254 mm oil drain extension made from standard pipe and fittings in the 1 2 inch 12 70 mm pipe tapped oil drain hole in the base CRANKCASE BREATHER INSERT A SOFT WIRE THROUGH BREATHER PIPE TO CLEAN BREATHER SYSTEM BALL JOINT PRIMARY SECONDARY FILTER FILTER DUAL FUEL FILTER SYSTEM FIGURE 2 MAINTENANCE PROCEDURES OUT OF SERVICE PROTECTION The natural lubricating qualities of No 2 diesel fuel should protect a diesel engine for at least 30 days when unit is not in service To protect an engine that will be out of service for more than 30 days proceed as follows 1 2 Run engine until thoroughly warm under at least 50 percent load Shut down engine and drain oil base while still warm Refill and attach a warning tag indicating viscosity of oil used Remove glow plugs Pour 1 ounce of rust inhibi tor or SAE 10 oil into each cylinder Install glow plugs Crank engine by hand only to distribute oil in cylinder Starter cranking is too fast oil or inhibitor fluid will fire if cranked with starter at normal room temperature Service air cleaner per Maintenance Schedule Clean throttle and governor linkage and protect by wrapping with a clean cloth Plug exha
62. ail completely into the loop and clinch before resoldering A good soldering job is necessary to ensure good contact and low voltage drop across the connection Over Running Clutch Clean the clutch thoroughly but do not dip in solvent It cannot be repacked with grease It should slide easily on the armature shaft with no binding Turn the pinion it should rotate smoothly but not necessarily freely Reversethe direction a few times anditshould instantly lock and unlock Replace the clutch if operation is defective or pinion is worn or damaged Shifting Solenoid See that the plunger moves freely in the coil Check pull in coil continuity between the solenoid control terminal and the solenoid connection to the motor Check the hold in coil continuity between the sole noid control terminal and ground on the motor 10 GEAR HOUSING SHIFT LEVER LINK SCREW A711 SHIFTING SOLENOID NS S f7 FIELD COIL POLE SHOE 2 ATOR CRUSH mmm oer wea emer ien ARMATURE SOLENOID PLUNGER FIGURE 88 STARTING MOTOR PRESTOLITE STARTER REMOVAL AND DISASSEMBLY Remove connections to controls and battery at shifting solenoid See Figure 88 Remove nut holding rear mounting bracket to engine Remove three capscrews holding starting motor flange to engine and pull out motor Remove link pin holding the shift lever to solenoid plunger and remove shift l
63. and follow the instructions provided by the supplier Chemical cleaners cannot be used with direct sea water cooled marine engines Cleaning solutions typically contain strong chemicals that may cause injury if used improperly Read all warning labels before using When cleaning is complete drain the cleaning solu tion and flush the system For best results the engine and heat exchanger should be reverse flushed Allow the engine to cool as much as possible before flush ing with cold water Never pour cold water into a hot engine Doing so may crack the head or the cylinder block Do not operate engine without coolant for even a few minutes Flush system if engine operation indicates clogged passages or overheating To flush the engine 1 Drain heatexchanger cylinder block and exhaust manifold Remove thermostats 2 Remove the inlet and outlet hoses between the engine and heat exchanger 3 Close all drain plugs and attach the flushing gun nozzle to the water outlet as near the exhaust manifold as practical Restrict the normal inlet line opening until the system fills with water then apply air pressure gradually Repeat the process until the flow of water from the cylinder block is clean 4 Remove flushing gun 5 Reinstall thermostats hoses and drain plugs and refill the system with the proper coolant 6 When flushing is completed check the system thoroughly for any leaks uncovered by the clean ing o
64. ation water is atits maximum This is necessary because the engine is often required to operate at its heaviest load when the boat is not moving For this reason a larger keel cooler is required for the generator set than would be required for a propulsion engine of equal size EXPANSION TANK ENGINE EXHAUST MANIFOLD FIGURE 11 KEEL COOLER WATER FLOW During normal operation marine cooling systems intake a greater amount of d rt and sediment than would be expected with radiator or city water cooling systems This contributes greatly to water pump wear and increases the chances that water passages will become clogged or restricted It is important with marine cooling systems that the water flow be checked frequently to insure that adequate cooling is maintained Sea Water All marine cooling systems except keel coolers with dry stack exhaust require a continuous flow of sea water for adequate cooling Anything that reduces or blocks the flow of water in the sea water system may cause overheating Remove the filter screen Figure 12 from the water filter on a periodic basis and clean away any accumulations of dirt and sediment Flush clean water through the screen before replacing the filter Also check all hoses and pipes to make sure there are no kinks or bends that could restrict water flow When the boat is dry docked the water inlet strainer located on outside of hull should also be checked foraccumulations of
65. ber of bends The radius of any bend in the exhaust pipe should be at least 5 times the diameter of the pipe The dry sections of exhaust line should be either insulated or water jacketed Be sure the slotted opening in the vacuum relief valve is open to aimos pheric pressure The siphon break will not function if the relief valve slot is closed in any way HANGER STRAPS VACUUM RELIEF VALVE ADAPTER ELBOW 2 RUBBER HOSE WATER OUTLET EXHAUST WATER INJECTION ELBOW EXHAUST OUTLET FIGURE 5 SIPHON BREAK EXHAUST GAS IS DEADLY Exhaust gases contain carbon monoxide a poisonous gas that might cause unconsciousness and death It is an odorless and colorless gas formed during combustion of hydrocarbon fuels Symptoms of carbon monoxide poisoning are e Dizziness Headache Weakness and Sleepiness e Vomiling e Muscular Twitching e Throbbing in Temples If you experience any of these symptoms get out into fresh air immediately shut down the unit and do not use until it has been inspected The best protection against carbon monoxide inhalation is proper installation and regular frequent inspections of the complete exhaust system I f you notice a change in the sound or appearance of exhaust system shut the unit down immediately and have it inspected and repaired at once by a competent mechanic 15 Cooling System INSPECTION As a part of standard maintenance procedures the entire coolin
66. bleeds off during shutdown periods When the lines are full of fuel only a couple turns of the crankshaft are required to build up enough line pressure for firing the injectors DELIVERY VALVE SEAT LINE PRESSURE FIGURE 46 DELIVERY VALVE CLOSED PLUNGER DOWN Keeping the fuel system clean is extremely important A fine particle of dirt can ruin the Injection system in a very short time If the fuel system is opened for any reason cap all openings and place the parts removed in clean diesel fuel Before installing new or used parts wash them in clean fuel and install them wet Preservative oil applied to the new injection pump during assembly may cause the pump to stick Forcing the plunger or gear will damage the pump Dissolve preservative by soak Ing pump in clean filtered diesel fuel for 15 to 30 minutes TIMING BUTTON CODE The timing button has a code number or letter stamped on it that corresponds to its dimension in thousandths of an inch See Table 8 Figure 47 shows the timing button One button will provide the correct port closing CODE LETTER OR NUMBER SA STAMPED ON SIDE FIGURE 47 TIMING BUTTON CODE TIMING BUTTON THICKNESS injection pump kits include a pump and four buttons which will time most of the engines The button and retainer ring are not assembled The injection pump on each engine must be timed to that engine by using a timing button of specific thick ness Each new pump has its
67. clearance back off the set screw until it just clears the rocker arm When reassembling the rocker cover remove the solenoid dip the plunger O ring in oil and rein stall when cover is on the engine Align solenoid so terminal SW is above terminal IGN INTERNAL DISASSEMBLY If engine disassembly is necessary observe the fol lowing order i e Flywheel Gear Cover As disas sembly progresses the order may be changed some what as will be self evident The engine assembly procedure is the reverse of disassembly Any special assembly instructions for a particular group are included in the applicable section When reassem bling check each section for these special assembly instructions or procedures FLYWHEEL Removethe blower housing Theflywheel is atapered fit on the crankshaft Improvise a puller using at least a 7 16 inch 11 113 mm bar and drill two 7 16 inch 11 113 mm holes 2 7 8 inches 73 025 mm between centers Loosen the flywheel mounting screw a few turns Place bar againstthe flywheel screw and attach bar using two 3 8 16 thread screws in the holes pro vided in flywheel Alternately tighten the screws until flywheel is free REPLACEMENT Replacement flywheels are supplied without the tim ing markings because each flywheel must be fitted to its engine The only accurate method of determining the top dead center TDC and port closing PC points is to measure the piston travel This isa critical measurem
68. commended grade Multemp PS No 2 e Armature shaft gear Reduction gear Ball bearing Both ends of armature Stopper on pinion shaft e Sleeve bearing e Pinion gear e Sliding portion of lever Pinion Shaft End Play Adjustment Adjust end play so that it is 0 1 to 0 8 mm 0 0039 to 0 0315 inch with the adjusting washers placed between center bracket and reduction gear Figure 95 n N REDUCTION GEAR va WASHER CENTER ADJUSTING WASHER BRACKET ES 1191 FIGURE 95 ADJUSTING PINION SHAFT END PLAY FRONT With pinion gear removed install reduction gear onto BRACKET pinion shaft Place pinion shaft into center bracket and secure with washer and snap ring Measure the end play with a feeler gauge between center bracket and gear If necessary adjust end play by adding or removing adjusting washers If pinion gear has not been removed place pinion PACKING shaft and reduction gear between front bracket and center bracket With lever spring removed and bolt tightened push pinion shaft out and measure end play Adjust end play if necessary by adding or re vi ims CENTER moving shims RAACH ET Pinion Gear Installation Place spring and pinion gear onto pinion shaft Slide stop ring onto pinion shaft and install retaining ring in groove Pull stop ring over retaining ring Figure 96 SPRING ES 1185 FIGURE 97 LEVER INSTALLATION Pinion Gap Adjustment After assembling starter motor
69. d Continuous running under one half load during the first few hundred hours may result in poor piston ring seating causing higher than normal oil consumption and blowby Drain and replace the crankcase oil after first 50 hours of opera tion drain while the engine is stil hot INSPECTION Check for alignment of engine and load Misalign ment will cause excessive vibration and bearing wear Make a visual inspection of the entire installation WARNING Contact with rotating machinery might cause serious personal injury or death Stay clear of rotating components and ensure that protective shields and guards are in place and secured before operating machinery VENTILATION Good ventilation is needed to cool the engine and to support combustion Avoid recirculation of ventilat ing air WARNING Inhalation of exhaust gases might result in serious personal injury or death Do not use exhaust heat to warm a room compariment or storage area EXHAUST Pipe exhaust gas outside any enclosure exhaust gas is poisonous Exhaust pipes must not terminate near inlet vents Avoid sharp bends Use sweeping large radius elbows Use a section of seamless flexibie tubing between the engine and any rigid pipe to res trict vibration BATTERIES Check the condition of the starting batteries at least every two weeks See that connections are clean and tight A light coating of non conductive grease will retard corrosion at terminals
70. d adjustment nut and governor spring bracket Remove the screws holding the gear cover to the crankcase To loosen the gear cover tap it with a soft hammer Governor Shaft The governor shaft is supported by two sets of needle bearings To remove the shaft remove the yoke and pull the shaft from the gear cover If the shaft is bind ing clean the bearings If loose replace the bearings To remove the larger bearing drive both bearing and oil seal out from the outside of the gear cover Removethe smaller bearing with an Easy Out or sim ilar tool Press new bearings and oil seal into place See Figure 106 Gear Cover Oil Seal Replace the oil seal if damaged or worn Drive the oil seal out from inside the gear cover Lay the cover ona board so the seal boss is supported Using an oil seal driver insert the new seal from the inside with rubber lip toward outside of gear cover open side of seal inward and drive it flush with the outside surface During gear cover installation use the driver to pro tect the oil seal See Figure 107 Assembly Gear Cover 1 Work governor shaft to check for binding and see that the governor shaft end thrust ball is in place Figure 106 Later models have larger ball which will not fail out 2 Turn governor yoke so smooth side is toward governor cup 3 Turn governor cup so stop pin in gear cover will fit into one of the holes in the cup surface Figure 108 Measure distance from end of sto
71. d crankshaft gear Set the two positioning dowels onthe upper bearing mount Install center main bearing cap and torque bolts to 97 102 ft Ib 131 138 Nm Check crankshaft end play Use enough rear bearing plate shims and gaskets to provide 0 010 inch 0 254 mm to 0 015 inch 0 381 mm end play If gaskets of more than 0 015 inch 0 381 total thickness are required use a steel shim of proper thickness and a thin gasket on each side of shim This avoids excessive gasket compression and maintains bolt torque Install piston assemblies LOCK PIN THRUST WASHER ALIGN OIL HOLES Crankcase If the crankcase requires replacement a new set of injection pump shims will be furnished with the new crankcase These must be used and in addition the injection pump must be re timed to the engine If on the four cylinder models the center main bearing support requires replacement the whole crankcase must be replaced or returned to the factory to have a new housing fitted Break In Period Whenever new rings or pistons are installed or the cylinder refinished the engine must be run in before regular operation can be resumed Runthe engine for 15 to 20 minutes at no load about 30 minutes at 1 3 load and 2 to 3 hours at 2 3 load Regular operation can then be resumed Avoid light load operation dur ing the following several hours for best ring seating and to prevent oil consumption INSTALL FLUSH WITH OUTSIDE SUR
72. d pump 1 109 28 169 Button thickness of old pump 107 2 719 Total 1 216 30 887 Port closing dimension of new pump 1 094 27 788 Required button thickness of new pump 122 3 099 4 Subtract port closing dimension given on new pump flange from total dimension for old pump 5 Use dimension calculated to select new timing button that is nearest the calculated dimension Install new timing button in pump and install tappet on pump 6 Install injection pump Referto INJECTION PUMP INSTALLATION MAXIMUM THROTTLE STOP SCREW ORIGINAL TIMING BUTTON PORT CLOSING CODE STAMPED DIMENSION STAMPED ON THIS FLANGE ON THIS FLANGE ees TEARS X FIGURE 48 TAPPET REMOVAL Method 2 Flow Timing Injection Pump This procedure is used when dimensions from the old pump are lost or when a new cylinder block is installed Clean diesel fuel is used when flow timing to determine if the proper timing button has been installed If the pump is removed from the engine be sure the steel shims between the pump and the cylinder block mounting arethe same These shims maintain proper gear backlash The number stamped on the cylinder block injection pump mounting pad indicates the proper shim thickness This thickness does not change when anew pumpis installed It changes only when a new cylinder block is installed 1 Install No 12 timing button in new injection pump Remove delivery valve cap nutand holder take out spring and r
73. d tappet for excess wear or improper assembly 4 Select the correct shims for the required thick ness 5 Install the pump DEPTH MICROMETER FIGURE 39 DEPTH MICROMETER Method 2 Flowing the Pump 1 install pump with 0 006 inch 0 15 mm shims between pump and pad 2 Loosen the delivery valve holder to relieve pressure on spring See Figure 40 3 Rotate the flywheel to about 15 degrees before the port closing PC point Blow in the pump inlet and rotate the flywheel slowly clockwise until air stops coming out of the pump outlet This is the port closing point 4 Measure the distance from the point where port closing occurs to the PC mark on the flywheel Find the thickness of shims to be added from the table that follows 5 Install the pump Qla at 4 i VA S DELIVERY RETUR FUEL RETURN VALVE SPRING a INJECTION PUMP TRANSFER PUMP 4 PRIMING LEVER FIGURE 40 LOOSENING DELIVERY VALVE HOLDER Installation Prior to mounting the injection pump to the cylinder block follow steps 1 through 3 1 Slide the shim or shims using proper thickness of shims for correct timing over the pilot until they are flat on the pump flange See Figure 41 2 Dip the seal O ring in engine lubricating oil 3 Slide the seal over the pilot until tight against the shim or shims 43 SHIM SELECTION USE THIS CHART WITH METHOD 2 All dimensions are in Inches DISTANC
74. e and avoids localized hot spots When the thermostat is not operating properly the engine may runtoo hot ortoo cold Overheating may damage the thermostat so that the valve will not func tion properly Also rust or corrosion may interfere with its operation Two thermostats are used on the 4 cylinder J series generator sets with front mount heat exchangers One thermostat is used on the 1 and 2 cylinder J series all and on 4 cylinder J series generator sets with side mounted heat exchangers Figure 27 shows the thermostat locations If a faulty thermostat is suspected remove it and test it for proper opening and closing Testing A defective thermostat may cause the engine to run too hot or too cold and must be replaced if faulty Thermostats should be tested for proper opening and closing If a sticking or faulty thermostat is sus pected test as follows 1 Remove thermostat from the cylinder head 2 Heat a pan of water to the opening temperature specified in Table 6 Check temperature using a thermometer immersed in water 3 With the thermostat suspended in water at the specified opening temperature check to see that the thermostat begins to open It should be possible to slip a 0 003 inch 0 08 mm feeler gauge between the valve and thermostat body 4 Continue heating the water until the temperature specified for full opening is reached Check to see that the thermostat is open by the amount speci fied in Table
75. e at the rocker box gaskets and oil filter seal ROCKER COVER Hot crankcase oil can cause burns if it Is spilled or splashed on skin Keep fingers and hands clear when removing the oil filter and wear protective clothing CYLINDER HEAD FIGURE 80 CRANKCASE BREATHER PIPE 64 CRANKCASE BREATHER MDJA Prior to Spec R The crankcase breather is located in the left rear corner of the crankcase and maintains a partial vacuum in the crankcase during engine operation Its purpose is to ventilate the crankcase and control oil loss It consists of a metal filter packed into the tube onthe crankcase a rubber cap with flapper valve and a hose connecting it to the engine air horn To disassemble remove the rubber cap from the crankcase tube and pry the valve out of the cap Wash the valve in fuel at regular intervals and if defective replace it At the same time pull the baffle out of the breather tube and clean it Install the valve with the perforated disk toward the engine Figure 81 shows the crankcase breather FLAPPER VALVE ASSEMBLY TUBE FRON CLEANER BREATHER M TUBE BAFFLE FIGURE 81 CRANKCASE BREATHER PULSATION DAMPER MDJC Begin Spec S and MDJF These engines are equipped with a pulsation damper which serves two major functions It dampens pulsa tions which originate in the intake manifold and which contribute to oil carry over It also acts as an oil separator to condense oil vapor and small oil drop
76. e belt guard EXPANSION TANK An expansion tank is required with heat exchanger and keel cooler cooling to allow for coolant expan sion and to provide for separation of air from the coolant With front mount heat exchangers and keel coolers a separate expansion tank is required With side mount heat exchangers the expansion tank is an integral part of the heat exchanger A pressure cap is fitted to the top of the tank to maintain system pressure PRESSURE CAP The pressure cap increases the boiling point of the coolant by allowing pressure to build up in the cool ing system The increase in boiling point reduces the chances for coolant loss due to boil over A 15 psi 103 5 kPa pressure cap will raise the boiling point of water to 250 F 122 C and the boiling point of a 50 50 mixture of water and antifreeze to 265 F 132 C Inspect the pressure cap periodically for freedom of operation and verify that the spring applies a fairly stiff tension and is not easily compressed Peel the pressure cap gasket back and check for wear and cracking Excessive dripping from the overflow tube may indicate a faulty cap Replace the cap if it mal functions or is worn WARNING Contact with hot coolant might result in serious burns Do not bleed hot pressurized coolant from a closed cooling system Pressure caps should be inspected regularly for gasket wear and spring action A pressure tester may be used if available to verify that th
77. e cap can hold its rated pressure value The pressure ratings for the various caps are shown in Table 4 Refer to the appropriate Parts Catalog for the pres sure cap part number TABLE 4 PRESSURE CAP TEST PART RATED ACCEPTABLE NUMBER PRESSURE PS LIMITS PSI 130 0589 14 12 15 97 kPa 83 98 kPa 130 0661 7 48 kPa 130 0824 15 98 kPa 130 0553 4 3 5 4 5 28 kPa 24 31 kPa HIGH TEMPERATURE CUT OUT SWITCH A high temperature cut off switch shuts down the engine if the coolant in the water jacket reachesa dangerously high temperature This normally closed switch is a safety device designed to protect the engine from damage caused by overheating see Figure 26 33 J SERIES WITH SEA WATER COOLING OR KEEL COOLER HIGH WATER TEMPERATURE CUT OFF SWITCH THERMOSTAT HOUSING FIGURE 26 HWTKO SWITCH When engine temperature rises beyond a specific point the switch opens breaking B allowing fuel solenoid to close on diese engines When coolant temperature lowers to a safe operating range the switch closes permitting engine restarting A second high temperature cut off switch is some times used with generator sets that have a water injected exhaust system The second switch is mounted on the exhaust elbow see Figure 13 If the exhaust system overheats the switch shuts down the generator set before the exhaust system components are damaged The two switches are w
78. e personal injury or death Disconnect ihe battery cable when repairs are made to the engine controls or generator Exhaust System GENERAL The exhaust system must efficiently expel all engine combustion products and muffle exhaust noises with minimum back pressure If back pressure is too high volumetric efficiency of the engine is reduced fuel economy drops exhaust temperature increases and valve life is shortened Back pressure must not exceed 27 inches 686 mm of water column for the rated load when measured with a manometer at the exhaust manifold Figure 3 Units of Full Measurement Load mars la Water 27 Ex Mercu Ounces _ 15 6 02 FIGURE 3 BACK PRESSURE TEST WITH MANOMETER EXHAUST SMOKE A light gray or light blue smoke may be a result of low ambient temperature and light load This smoke is unburned fuel not harmful to the engine and disap pears when more load is applied Black smoke indicates overfueling more fuel than oxygen and is usually caused by overloading The smoke or unburned fuel becomes carbon when raised to a high temperature Carbon contributes to engine damage because it contaminates the lubricat ing oil Inhalation of exhaust gases might result in serious personal injury or death Do not use exhaust heat to warm a room compartment or storage area Vent exhaust gases outside Use flexible tubing only between the engine exhaust outlet and rigid piping 14 I
79. e steel strip will become magnetized and vibrate Rotate the armature slightly and repeat the test Do this for one complete revolution of the armature If the armature has a short or ground replace it If the commutator is only dirty or discolored clean it with 00 or 000 sandpaper Blow sand out of rotor after cleaning If however itis scored rough or worn turn it down in a lathe Field Coils Using atest lamp and probes check the field coils for grounding to the motor frame or open circuit Inspect ail connections to be sure they are properly clinched and soldered Inspect the insulation for evidences of damage The only way to check for field coil shorts is to use the starting motor test Bearings If either the front or rear bearings show excessive wear replace them Drive the old bearings out and using an arbor press and the proper arbor press new bearings into place Brushes Check the brushes for wear or improper seating They should slide freely in their holders Check the brush spring tension with a spring scale To change spring tension twistthe spring atthe holder with long nosed pliers Replace Prestolite brushes when excessively worn or when worn to 5 8 inch in length Replace Mitsubi shi brushes when excessively worn or when worn to 7 16 inch in length Some brushes are soldered to the field coil To remove these brushes unsolderthe lead and open the loop in the field coil lead Insert the new brush pigt
80. ection pump or valve train damage from lack of lubrica tion ensure that all restriction orifices are kept open Cleaning can be done using a fine wire or drill bitand compressed air 0 028 inch size at heads 0 71 mm 0 046 inch size at Tee 1 17 mm OIL FILTER Full Flow The oil filter is mounted on the filter plate at the left side of crankcase Figure 78 It requires replacement every 200 hours of normal operation Remove filter by turning counterclockwise using a filter wrench Install new filter finger tight plus 1 4 to 1 2 turn FIGURE 78 FULL FLOW OIL FILTER CRANKCASE BREATHER MDJA Begin Spec R MDJB Begin Spec S and These engines are equipped with a ball check valve for maintaining crankcase vacuum The only mainte nance required is to clean the components periodi cally Remove the hose clamp breather hose and breather cap clamp to release the breather cap and valve assembly Wash cap and valve assembly and the baffle in suitable solvent and reinstall BREATHER HOSE HOSE CLAMP CAP AND VALVE FIGURE 79 CRANKCASE BREATHER CRANKCASE BREATHER MDJC MDJF Begin Spec T These engines are equipped with a crankcase breather pipe that vents crankcase fumes directly from the rocker box cover to the cylinder head intake port see Figure 80 The crankcase breather pipe must be removed and cleaned after every 500 hours of engine operation A clogged breather pipe may result in oil leakag
81. ed plunger is forced down opening the fuel supply portto the fuel sump This allows fuel under low pressure from the transfer pump and fuel sump to fill the cavity between the top end of the plunger and the delivery valve The plunger is then ready for the up stroke SEAL DELIVERY VALVE OUTLET coke PLUNGER all METERING SLEEVE E NNG e SPRING FACE GEAR TIMING BUTTON INJECTION PUMP CUTAWAY VIEW Metering Sleeve Operation The metering sleeve is positioned by the operating lever of the governor control unit Figure 45 An eccentric pin on the end of the control shaft engages aslot in the metering sleeve so that a slight rotation of the control shaft causes the sleeve to ride up or down onthe plunger Asthe camshaft and face gear rotate the drive key and a vertical slot in the face gear trans mit rotation to the plunger Rotating the plunger aligns outlet groove with the appropriate injection line outlet for the injector to fire on each pump stroke OPERATING ECCENTRIC PIN FIGURE 45 METERING CONTROL 4 Delivery Valve Function The delivery valve maintains 300 to 600 psi 2070 to 4140 kPa line pressure in the injector lines with the engine running Figure 46 This pressure increases to about 1900 psi 18110 kPa on each stroke of the injection pump plunger The trapped fuel is held in the lines atall times even though the pressure
82. edure for assembly Figure 99 Brush Assembly Tests Test brush assembly as follows 1 Connect an ohmmeter or test lamp 12 volts to the field terminal and to the bracket The test lamp should not light or resistance reading should be high infinite If not there is a short and the assembly must be replaced 2 Move one ohmmeter lead from the bracket to insulated brush Use an alligator clip directly on the brush Be careful not to chip it Resistance reading should be zero continuity 3 Connect ohmmeter leads to the grounded brush and the bracket Resistance should be zero continuity n VOLTAGE REGULATOR MOUNTS HERE 8 32 SCREWS FIGURE 99 OPTIONAL BATTERY CHARGING EXTERNAL ALTERNATOR Engine Disassembly ENGINE REBUILDING When engine disassembly is necessary remove complete assemblies tear down individual compo nents like fuel pump breaker mechanism etc as bench jobs Use special tools available Disassembly Common sense will dictate proper order of disas sembly As disassembly progresses the order may be changed as will become self evident A suggested procedure would be as follows 1 Radiator water pump 2 Flywheel using puller or pry bar method 3 Gear Cover protect oil seal from keyway damage 4 Crank Gear use puller and gear puller ring Loosen accessories such as fuel pumps and oil filter Starter motor Drain oil discard oil removed Cylinde
83. ei eps 1 361 1 362 34 570 34 595 Depth from Cylinder Head Face D 433 439 10 99 11 15 Seat Outside Diameter Exhaust sr erase err a ka s idis 1 364 1 365 34 6456 34 6710 Intake eee rtr Pene Ribeiro ust dr see wanes 1 550 1 551 39 37 39 39 Seat Width s eU Me PI E OUR eus PEE ESSE MESE Sedi 047 062 1 19 1 57 Dun MEE 45 Available Insert 5 cence tent eet ese he hee 002 0508 005 127 010 254 025 635 VALVE SPRINGS Load Valve Closed cere ences ehem 45 49 Ib 200 218 N Load Valve Open Prior to Spec P 83 93 Ib 369 414 N Load Valve Open Begin Spec AUS arduo Deere eta cele S 87 97 Ib 388 432 N Newton Base unit of force Measure intake valve stem at points indicated Valve Stem Diameter Intake FACE 2 96 IN 75 2 mm 1 CENTER 1 18 IN 80 0 mm Assembly Torques and Special Tools The assembly torques given here will assure proper tightness without danger of stripping threads If a torque wrench is not available estimate the degree of tightness necessary for the stud nut or screw Be careful notto strip threads Use only reasonable force and a wrench of normal length Specially d
84. el return line PRE HEATING AND STARTING Preheating for 60 seconds is recommended on all DJ Series Diesels at 55 F 13 C or lower and 30 seconds for temperatures above 55 F 13 C Refer to Onan Diesel Starting Guide for additional starting guidelines WARNING Inhalation of exhaust gases might result in serious personal injury or death Be sure deadly exhaust gas is piped outside and away from windows doors or other inlets to building Use of ether as a starting aid might cause an explosion resulting in severe personal injury and engine damage Do not use ether as a starting aid heat or compression or heat from the glow plugs may cause a sudden ignition of the ether vapor 1 Engage PREHEAT switch for the time period recommended below 30 seconds if above 55 F 13 60 seconds if below 55 F 13 C 2 Engage START switch while continuing preheat Hold until engine comes up to speed 3 If engine fails to start in 15 20 seconds repeat steps 1 amp 2 Absence of blue exhaust smoke dur ing cranking indicates no fuel being delivered Determine cause In extreme cold it may be necessary to maintain preheating up to 2 minutes after the engine starts to obtain firing or to smooth out all cylinders especially at no load or light loads Do not exceed the one minute preheat periods to prevent heat er burn out and conserve the battery Longer preheating time prior to cranking the engine can ru
85. ent and should be attempted only with accurate reliable equipment With the flywheel mounted remove the head and install a depth gauge over the front piston Rotate the flywheel to find the TDC position on the compression stroke and mark this point on the flywheel Next turn the flywheel counterclockwise until the piston drop is as specified in Table 9 Mark both TDC and piston drop to PC point on the flywheel TABLE 9 PISTON DROP DATA PORT PISTON DROP CLOSING MDJA 0 102 17 degrees MDJB amp MDJC 19 degrees Begin Spec P mm Prior to Spec 325 29 325 0 128 MDJE Spec A AA 19 degrees 0 115 MDJE Begin Spec AB 18 degrees 0 128 MDJF 19 degrees Ring Gear To remove a damaged ring gear saw part way through then break it using a cold chisel and heavy hammer To install a new ring gear placeit in an oven heated to 380 F 400 F 192 to 204 C for 30 to 40 minutes Do not heat ring gear to a bright red as ring gear may warp and the heat treatment will be destroyed When properly heated ring will fall into place on flywheel if it does not go on ali the way by itself drive it into place with a hammer Do it fast and do not damage the gear teeth Ring will contract rapidly and may shrink to the flywheel before it is in place If this occurs new ring gear may be required GEAR COVER Toremovethe gear cover detach the upper governor ball joint Remove the governor spee
86. epair The injection pump is an expensive part of the unit and even a particle of dirt as fine as talcum powder could score its working surfaces 9 Removal If the rest of the fuel system is in working order and fuel delivery abnormal remove the pump for replace ment or repair x 1 Locate injection pump on service side of engine and remove necessary sheet metal and hardware to make pump accessible 2 Remove fuel inlet and return line Figure 57 3 Remove high pressure lines between pump and injector nozzles both ends 4 Cap all lines and fittings using extreme care to keep al fuel system components clean 5 Remove four socket head screws holding pump to adapter assembly 6 Position fuel control shaft and yoke as shown in Figure61 Then lift pump off of adapter assembly 7 Carefully clean injection pump assembly and place it in a clean place Retain shims between pump and adapter as they are needed for reassembly INJECTION PUMP ADAPTER The cast iron adapter Figure 60 is the crankcase mounting fixture for the fuel injection pump and its fuel control arm yoke and overfueling control device A composition gasket is used between the adapter and the crankcase Thefuel control arm and the shaft and yoke assembly transmit governor action to the injection pump con trol rack The overfueling device provides maximum excess fuel during engine starting and limits the maximum amount of fuel and engine power
87. eplace valve holder and cap nut Figure 49 and 50 SPRING CAP NUT FIGURE 49 LATE MODEL DELIVERY VALVE ASSEMBLY GASKET CAP SCREW FIGURE 50 EARLY MODEL DELIVERY VALVE HOLDER 2 Install new injection pump Refer to INJECTION PUMP INSTALLATION 3 Remove No 1 injection line Install No 1 injection line with top end of line in pump outlet Place an open container under open end of No 1 injection line Figure 51 4 Disconnect governor linkage at ball joint and hold control arm up at maximum fuel position RETURN LINES SHADED oe See _ CONNECT 2 5 FUEL RETURN 27 LINE HERE TEST FLEXIBLE LINE y POSITION A642 1 FIGURE 51 FUEL LINE TO INJECTORS 5 Rotate flywheel clockwise when facing front of engine Figure 52 to point where PC mark on flywheel is about 15 degrees 1 25 to 1 50 inch 32 38 before timing pointer on gear cover compression stroke of No 1 cylinder Makesurethat both rocker arms on No 1 cylinder are free to move indicating the valves are closed If fuel tank is disconnected use a separate con teiner of fuel and connect a short fuel line between thetransfer pump inlet and the fuel con tainer The pump has enough suction to pull fuel out of the container Ignition of fuel might cause serious personal injury or death by fire or explosion Do not permit any flame cigarette or other igniter near the fuel system TIM
88. es cover more than one engine Therefore select gasket of correct size and shape for part being used Always use new gaskets 6 When disassembling engine mike bearing plate gasket thickness Then select proper shim thick ness for correct end play Shims establish end play Only one thickness gasket is included in kit 7 When assembling crankshaft make sure bearing thrust washers are in proper position supported by bearing stop pins Use cup grease to hold in place 8 When adjusting valve lash tap rocker arm so it is straight when checking with feeler gauge 9 Crank gears are easier to remove and install if heated a slight amount Do not overheat or temper may be lost and shaft may expand 10 See FUEL SYSTEM section for correct engine timing 11 Allow some gear lash approximately 0 005 inch 0 13 mm in oil pump Do not install gears tightly against each other TESTING AND ADJUSTING ENGINES Preparation Check the following Put proper oil in crankcase Service air cleaner Connect fuel line Connect load Connect fully charged battery Check ventilation for proper cooling WON Operation 1 Start engine see Diesel Starting Guide 2 Check oil pressure 3 Run unit 15 minutes to bring it up to operating temperature 4 Check for oil leaks loose electrical connections tight fuel lines and tight exhaust connections Adjustments Adjust governor for speed and sensitivity
89. esigned place bolts do not require a lock washer or gasket Do not attempt to use alockwasher with these bolts it will defeat their purpose Check all studs nuts and screws often and tighten as needed to keep them from working loose SPECIAL TOOLS These tools are available from Onan to aid service and repair work Diesel Nozzle Tester 420 0184 Diesel Pintle Nozzle Cleaning Tool Set includes injection nozzle centering 420 0208 Driver Center Camshaft Bearing RDJF only cece cece eee ee eee 420 0254 Driver Valve 420 0270 Oil Seal Guide and Driver 420 0456 Nozzle Centering Sleeve 420 0321 Delivery Valve Test Fixture 420 0322 Combination Main and Cam Bearing 420 0326 Diesel Compression Tester 420 0283 Valve Spring Compressor Tool 420 0119 Valve 420 0311 Flywheel 420 0100 Crankshaft Gear Puller AMAT 420 0072 Crankshaft Gear Pulling Ring 420 0248 Tool Catalog 900 0019 RECESS SONS UNDER HEAD A749 TORQUE SPECIFICATIONS Ft Lb Nem Center main bolt 4 cylinder 97 102 131 138 Connecting rod bolt 27 29 37 39 Rocker Box 8 10
90. ever center pin Remove through bolts from commutator end of motor Pull off end cover and lift brushes off their seats Pull pinion housing from front end of motor and lift armature and clutch out of motor frame To remove over running clutch from armature drive retainer away from lock ring near front end of shaft remove lock ring and pull assembly off Do not attempt to disassemble cluth assembly If necessary to service solenoid remove four capscrews and electrical connection holding itto motor frame Remove two screws on rear of sole noid to reach switch contacts Mount starter motor to engine by a direct reversal of the removal procedure Figure 89 Connect battery cable and wires to starter Connect baitery cables to battery Connect ground last BSTARTING MOTOR AND FLANGE FIGURE 89 STARTING MOTOR FLANGE PRESTOLITE STARTER ASSEMBLY Before assembling soak the bronze bearings in oil They are absorbent bearings designed to hold up to 25 percent of their own weight in oil Be sure the felt oil pad is in the outer end of the commutator end bearing When the motor is assembled check the armature end play lt should be between 0 005 inch 0 127 mm and 0 030 inch 0 762 mm Adjust end play by adding or removing washers on the commutator end of the armature Before installing check the pinion clearance Proper clearance is important to ensure starter engagement Press on solenoid core
91. f it is much greater the contacts did not open The solenoid plunger should be adjusted so it fully stops injection when in the de energized position To adjust the plunger length turn the screw and jam nut on the plunger bottom in or out If the plunger sticks remove the solenoid from its mounting plate and clean the plunger and recess in the solenoid FUEL INJECTION PUMPS Onan DJ series diesels are equipped with American Bosch fuel injection pumps Single cylinder engines use the model PLB the four cylinder engines use the model PSU pump Until recently the two cylinder diesel engines have been using a PSU pump Now the MDJE engines use either a Bryce or a Kiki fuel injection pump For Bryce Kiki pump information turn to the back of this section The fuel injection pumps are constant stroke lapped plunger type and operated by the engine camshaft They deliver an accurately measured quantity of fuel under high pressure to the injection nozzles A constant bleed check valve is furnished with PLB and PSU pumps The bleed valve automatically bleeds off a restricted amount of fuel fuel vapors and smal quantities of airto prevent air accumulation in the fuel sump area of the pumps This valve should open at pressures between 0 9 and 3 0 psi 6 2 and 20 7 kPa The port closing PC mark is not stamped on replacement fiy wheels Therefore the PC mark must be established by measuring the piston drop with the cylinder head remo
92. ft Figure 92 WASHER amp 5 1195 SNAP RING FIGURE 92 REMOVING SNAP RING AND WASHER 6 Remove capscrew that secures center bracket to front bracket Remove the center bracket several washers used to adjust pinion shaft end play can now be removed Figure 93 CENTER BRACKET c END PLAY ADJUSTMENT WASHERS er FIGURE 93 REMOVING CENTER BRACKET ES 1187 Ti 7 Remove gear spring set and lever assembly from front bracket Note direction in which the lever assembly is installed 8 Push pinion gear and stopper down and remove retaining ring Remove stopper pinion gear spring and pinion shaft assembly FIBER FRONT WASHERS BRACKET LEVER OVERRUNNING CLUTCH CENTER 9 Inspect ball bearings If they are rough or noisy when rotated replace them The front bearing is not replaceable and must be replaced with the bracket SOLENOID TERMINAL M ARMATURE BEARING THROUGH BOLT REAR BRACKET T SCREW BRACKET SHAFT END PLAY ADJUSTMENT PINION WASHER SPRING STOPPER SPRING RETAINING BRUSH RING FRAME HOLDER ASSEMBLY ASSEMBLY XES 1255 FIGURE 94 MITSUBISHI STARTER OVERRUNNING PINION SHAFT CLUTCH MITSUBISHI STARTER ASSEMBLY PINION GEAR SNAP RING For assembly reverse the disassembly procedure but note the following items See Figure 94 Whenever starter motor is disassembled apply grease to each of the following points Re
93. g system should be inspected for signs of leakage and checked for worn components In spect the water pump bearings impeller neoprene and seals for signs of wear and check for correct drive belt tension Locate the source of any leaks and correct as required Inspect the zinc pencils on heat exchanger cooled engines and note the amount of deterioration Refer to the appropriate section for recommended service procedures As a final check run the engine at full load and verify that the engine can maintain an operating tempera ture of approximately 180 F 82 C An engine that operates significantly above or below this value should be tested for malfunctions IMPORTANCE OF REGULAR MAINTENANCE The entire cooling system including the block and radiator heat exchanger or keel cooler should be cleaned and flushed out at least once a year This is especially important in cold weather conditions or when preparing the unit for extended storage over 30 days The cooling system can work efficiently only when it is clean A build up of rust and scale in the cooling system will slow down heat absorption and restrict water flow PRESSURE CAP DRAIN PLUG EXHAUST MANIFOLD DRAINING COOLING SYSTEM Open all drains and hose connections where coolant may be trapped when changing the antifreeze solu tion or when preparing a unit for storage in freezing conditions Open the fill vent valve when draining heat exhanger cooled eng
94. g to allow engine to build up oil pressure and close the switch The switch closes at 13 to 15 psi 90 to 104 kPa under increasing pressure If oil pressure falls below 13 psi 90 kPa the switch opens 22 OIL FILTER FIGURE 83 LOW OIL PRESSURE SWITCH CENTRIFUGAL SWITCH This switch Figure 84 is mounted on the gear cover backplate and operates directly off the camshaft gear Normally open the switch closes when engine speed builds up to about 900 rpm This allows the engine to build up sufficient oil pressure so that it can be started For correct operation maintain the switch gap at 0 020 inch 0 51 mm See Figure 85 Check the contacts for dirt or pitting when adjusting the gap Clean the contacts with paper or replace if they are badly pitted BREAKER POINTS PLUNGER FIGURE 84 CENTRIFUGAL SWITCH ASSEMBLY Disassembly 1 Disconnect the battery to prevent accidental shorts 2 Remove the switch cover to reveal the point set 3 Remove the point set assembly by removing the screws holding it to the plate Pull outthe plunger and plunger diaphragm 4 Removethe centrifugal switch plate to reveal the cam and weight assembly 5 Pull out the cam and weight assembly Be careful not to lose the spacer mounted on the gear shaft behind the gear CENTRIFUGAL WT BREAKER POINTS SET GAP AT 0 020 INCH 0 51 mm FIGURE 85 BREAKER POINTS Repair Thoroughly clean the gear and cam a
95. gher fuel consumption and the opposite is the case when timing is advanced Torque Instructions The following torque instructions are for Bryce Kiki Injection Systems on Onan Engines Figure 66 Bryce Pump Model FAOBRO70E0686 Kiki Pump Model NP PFR2K70 1NP22 and 1NP23 Delivery Valve Retainer Bryce 28 5 to 32 ft Ib 39 to 43 Nm Kiki 43 5 to 47 ft Ib 60 to 64 Nm When using a new delivery valve gasket on Kiki pumps tighten the valve to full torque value and loosen twice then torque retainer a third time to seat the gasket finally e Fuel Inlet Stud both 15 to 18 ft Ib 2010 24 Nm e Bleed Fitting Retainer both 35 to 52 Ib inch 47 to 70 Nm All Adapter amp Pump Mounting Screws 20 to 24 ft Ib 27 to 33 Nm FUEL CONTROL ARM SHAFT BLEED FITTING RESTRICTED INJECTION PUMP ADAPTER GASKET INLET FITTING DELIVERY VALVE B RETAINER OVER FUELING DEVICE CAPPED HIGH PRESSURE LINE CONNECTION 5 16 x 18 SOCKET HEAD SCREWS WITH LOCKWASHERS 8 EACH SHIMS FIGURE 66 BRYCE KIKI PUMP AND ADAPTER ASSEMBLY TROUBLESHOOTING PUMP PROBLEMS Normally little goes wrong with the injection pump after it is installed on the engine as long as timing is correct and clean fuel is used continually The most common problem is caused by a delivery valve that may be held open by dirt or metal chips that entered the pump orfuel system during assembly and installation T
96. gineserial number Use 0 005 inch 0 127 mm oversize rings FIGURE 108 GOVERNOR CUP for these pistons Removal and Disassembly On2 and 4 cylinder engines the connecting rod and cap are stamped for installation in the proper cylinder When removing piston assemblies check the mark ing so each can be installed in the proper cylinder 1 Drain crankcase oil and remove oil base 2 Remove cylinder heads 3 Before pushing pistons out scrape carbon at top of cylinder bore 4 Remove cap from each connecting rod and push assembly through top of cylinder bore Replace cap and bearing inserts in proper assembly 5 Using a ring expander remove rings from each piston 6 Remove two retaining rings and push piston pin from each piston Cylinders The cylinder walls should be free of scratches pit ting and scuffing Check each with an inside reading micrometer for out of round and wear The bore measurement should be as specified and be less than 0 001 inch 0 0254 mm out of round If necessary rebore the cylinder to fit the next availa ble oversize piston Pistons and rings are available in 0 005 0 010 0 020 0 030 and 0 040 inch 0 127 2 540 0 508 0 762 1 016 mm oversize If the cylind ers do not need refinishing remove any existing ridges from the top of the walls with a fine stone Pistons Clean thoroughly and inspect each piston Clean the carbon from the ring grooves and be sure all oil holes are open If a
97. hat is the reason protective covers must be used to keep foreign matter out of unassembled fuel system components If the pump is suspected of causing misfires or poor operation Check the temperature of each nozzle holder and exhaust port the coolest cylinder is the faulty one Fuel penetration of the skin might cause severe personal injury Do not let the nozzle high pressure fuel spray against skin surfaces Loosen crack the high pressure injection lines one cylinder at a time like disconnecting a spark plug wire to determine the faulty cylinder the cylinder that looses the least power is misfiring or not firing Pump disassembly by unqualified personnel is not authorized and may void the pump warranty Return all faulty pumps to the Onan factory for repairs or replacement if still under warranty Otherwise refer all Ser vice problems to authorized Bryce Lucas and Diesel Kiki ser vice centers THROTTLING PINTLE NOZZLE TESTS The following tests will determine nozzle conditions using a manually operated test stand Each nozzle must be removed from the engine for testing Prior to testing each nozzle must be cleaned decarboned and inspected as described for non throttling pintle type nozzles earlier in this section New or recondi tioned nozzles must bethoroughly cleaned in cleaning solvent or test oil to remove all traces of preservative grease before testing The nozzle valve and nozzle body are lap f
98. ice side of the engine uses a transfer pump to deliver fuel from the tank to a high pressure injection pump at about 12 to 14 psi 83 97 kPa 5 6 psi on MDJA 35 41 kPa The injection lines deliver fuel to the injectors at high pressure and act as fuel distributors to the injectors The time interval between injection of individual injectors is varied inthe pump by engine speed From the injection pump metered fuel is forced through a delivery valve to the injector lines at about 1900 psi 13 110 kPa As the cylinder air reaches about 1000 F 538 C on the compression stroke the injec tor sprays fuel into the hot compressed air where it ignites The delivery valve in the injection pump and a pintle valve in the injector assist the precision timed injection of fuel into the cylinder FILTER SYSTEM The sediment bowl has a fine mesh screen which blocks dirt and water entry into the transfer pump Figure 28 29 The dirt and water remain in the sedi ment bowl which should be removed for cleaning as required The spin on primary and secondary fuel filters are replaceable units that clean the fuel of extremey fine particies before it goes to the injection pump These filters are mounted on a common casting which bolts to the oil fill tube Positive filtration is assured becausethe engine will not run if either filter is loose or missing Average pore size of the second filter is 0 0005 inch 0 0127 mm smaller than the first filter
99. in the manifold heater and glow plugs because there is no incoming air flow to cool them Addi tional operation of the preheaters for a few seconds during cranking in cold weather may help to preheat the incoming combustion air and prevent misfires as the engine starts running Verify that oil pressure gauge reads at least 20 psi after engine reaches speed pressure relief valve is not adjustable Do notapply overvoltage to the starting circuit at any time Overvoltage will destroy the glow plugs and air heater If it becomes necessary to use an addi tional source of power to start the set use a 12 volt battery connected in parallel STOPPING Push fuel solenoid switch to Stop position 2 Release switch when set stops If stop circuit fails close fue valve ONAN DIESEL STARTING GUIDE INDUSTRIAL ENGINES BEFORE STARTING TO PRIME FUEL SYSTEM MOVEPRIMING LEVERUP AND DOWN UNTiL FUEL FLOWS STEADILY FROM RETURN LINE DISCON NECTED FUEL TRANSFER PUMP PRIMING LEVER FUEL RETURN LINE gt TO START CHECK FUEL SUPPLY BE SURE SHUTOFF VALVES ARE OPEN PRIME FUELSYSTEMIF FUEL FILTERS WERE DRAINED OR CHANGED z SYSTEM WAS JUST INSTALLED FUEL TANK RAN DRY AIR HEATER ELEMENT IN MANIFOLD L gt T INJECTION NOZZLE 45 PREHEAT COLD ENGINE PUSH PREHEAT SWITCH AND HOLD 30 SECONDS IF ABOVE 55 F 13 C 60 SECONDS IF BELOW 55 F 13 C NEVER PREHEAT MORE THAN 60
100. ines The following drain plugs and hoses must be removed to drain the cool ing system completely Contact with hot coolant might result in serious burns Do not bleed hot pressurized coolant from a closed cooling system Engine Block J Series Remove drain plug on left front side of engine See Figure 6 Water Pumps All Units Remove drain plug under pump or loosen pump cover Figure 6 Exhaust Manifold Remove plug from underside of exhaust manifold Figure 6 Expansion Tank Remove plug from front side of expansion tank Figure 6 Heat Exchanger Draining Raw Water or Sea Water Remove drain plug from underside loosen end cover or loosen and remove hose to drain heat exchanger Tank Heater Loosen and remove lower hose to drain tank heater Aqualift Muffler The Aqualift muffler has relatively little water in it during normal operation and does not have to be drained during freezing weather Replace and tighten all plugs fittings and pampe when draining is finished DRAIN BLOCK HERE i SAVER VIPE j REMOVE PUMP PLUG COVER TO DRAIN J SERIES BLOCK WATER PUMP FIGURE 6 DRAINING COOLING SYSTEM 16 CLEANING AND FLUSHING THE COOLING SYSTEM To clean rust and scale deposits from captive water systems drain the system as previously described and then fill with clean water and cleaner solution Use an approved chemical cleaner such as the type used for cleaning automotive cooling systems
101. ions and procedures presented in each section apply to the engines listed on the cover The flywheel end of the engine is the front end so right and left sides are determined by viewing the engine from the front The disassembly section contains major overhaul procedures for step by step removal disassembly inspection repair and assembly of the engine components Ifa major repair or an overhaul is necessary a compe tent mechanic should either do the job or supervise and check the work of the mechanic assigned to do the job to ensure that all dimensions clearances and torque values are within the specified tolerances The wiring diagram shows how the electrical compo nents are interconnected A parts catalog available at the dealer level contains detailed exploded views of each assembly and the individual piece part numbers and their proper names fot ordering replacement parts Use only Genuine Onan replacement parts to ensure quality and the best possible repair and overhaul results When ordering parts always use the com plete Model and Spec number in addition to the Serial number shown on the nameplate ENGINE MODEL REFERENCE Identify your model by referring to the MODEL and SPEC specification NO as shown on the unit nameplate Always use this number and the engine serial number when making reference to your engine Howto interpret MODEL and SPEC NO on generator set engines 12 0MDJC 3R 96 A I 4 1 2 3
102. ipe plugs that are placed in one end of the heat exchanger 22 Ve ey CENTRIFUGAL A amp WATER PUMP DF IR tct IS WATER COOLED EXHAUST MANIFOLD 271 FIGURE 15 FRONT MOUNT HEAT EXCHANGER The side mount type of heat exchanger shown in Figure 16 is used with later models of the MDJC and It is mounted on the side of the engine just abovethe exhaust manifold The end caps are removable for cleaning and the expansion tank is incorporated with the outside shell On some models the sea water side of the heat exchanger is protected from corrosion with a zinc pencil located close to the sea water inlet Other models may not have zinc pencils AIR BLEEDER VALVE HEAT EXCHANGER x 29 EQ ZS di Sy Fit car erat A SL D cA E 2 b EXHAUST MANIFOLD EXHAUST AND RAW WATER DISCHARGE CENTRIFUGAL PUMP FIGURE 16 SIDE MOUNT HEAT EXCHANGER Sea Water Side Remove and inspect the zinc pencils that are used for corrosion protection every two months Replace if the pencils are deteriorated to less than one half their original size The sea water side of the heat exchanger should be inspected and cleaned on a yearly basis Remove the two end caps and flush out any deposits that may have accumulated in the tubes Be certain to note the position of the gaskets when removing the heat exchanger ends On some models the gaskets direct the water flow and when replaced must be
103. ired together in series so that opening either switch wil shut down the engine Stopping of the engine due to action of the high temperature cut off switch is not a normal condition Examine the cooling system to determine the cause of the overheating and repair as required The open ing and closing temperatures for each switch are shown in Table 5 Refer to the appropriate Parts Catalog for the part number of the high temperature cut out switch used in the engine being serviced TABLE 5 HIGH TEMP CUT OUT SWITCH PART TEMPERATURE F NUMBER _ OPEN 309 0259 309 0179 309 0178 309 0002 309 0151 309 0156 309 0252 309 0192 230 7 110 C 88 190 9 215 5 205 5 200 7 160 7 230 7 110 C 160 7 71 250 12 121 C 88 102 C 97 C 93 C 71 C 190 180 160 5 200 5 250 5 200 5 290 8 THERMOSTAT The thermostat is a heat operated valve that controls engine temperature by regulating the amount of heated coolant that is discharged direct flow or recirculated heat exchanger and keel cooler Asthe engine temperature increases the thermostat opens and allows coolant to circulate Prior to the thermo stat opening a small amount of coolant circulates through an internal by pass The continuous circu lation of the coolant through the by pass allows the various parts of the engine to warm up at a uniform rat
104. is not recommended for salt water or water that contains silt and debris WATER TO aoe LINE FLEXIBLE PITCH SECTION DOWN MUFFLER STRAINER 7 FIGURE 9 DIRECT SEA WATER COOLING THERMOSTAT HOUSING WATER MANIFOLD 222 ENGINE DRIVEN X WATER PUMP SEA WATER qs A ri 2 39 1 e 8162 t INLET SEA WATER CENTRIFUGAL PUMP FRESH WATER ES FRONT CYLINDER BLOCK CONNECTION SIPHON BREAK Im VACUUM RELIEF he VALVE Jd ADAPTER ELBOW 2 109 BLEEDER VALVE EXHAUST g MANIFOLD REAR CYLINDER BLOCK CONNECTION a RUBBER HOSE EXHAUST WATER DISCHARGE SEA WATER FRESH WATER IN CLOSED SYSTEM FIGURE 10 HEAT EXCHANGER COOLING Heat Exchanger Cooling System Marine heat exchanger cooling systems work using the same principle as city water heat exchanger sys tems Cool water from an unlimited source flotation water is circulated by the sea water pump through a set of tubes encased within a surrounding shell Fig ure 10 Engine coolantis circulated through the shell but is not mixed with the sea water A second water pump is used to circulate the engine coolant in the captive system The sea water passing through the heat exchanger tubes absorbs the heat from the engine coolant The heated sea water is discharged through the exhaust system Figure 10 shows a schematic of atypical marine heat exchanger cooli
105. itted together and must not be interchanged 57 Visual Check Using illuminated Magnifier 1 Inspect nozzle valve for damaged or rough seat 2 Inspect pintle for wear damage or out of round spray hole 3 Check nozzle body for damaged or carboned seat Slide Test 1 Dipclean nozzle valve in filtered diesel fuel or test oil 2 insert valve in nozzle body Figure 67 3 Holding body almost vertically pull valve out to one third of its engaged length then release valve 4 Thereleased valve because of its weight should slide down to its seat CAPNUT ADJUSTING SCREW LOCKNUT SPRING CAPNUT FIGURE 67 SLIDE TEST FIGURE 68 NOZZLE ADJUSTMENT KIKI NOZZLE ADJUSTMENT Testing Nozzles with Hand Operated Tester If the opening pressure is incorrect connect nozzle to a tester and hold the nozzle in a suitable holder or The propertester can be used to check opening pres smooth jaw vise sure leak down rate chatter and spray pattern Install cleaned and inspected nozzle in tester and 1 Remove cap nut Figure 68 proceed as follows 2 Loosen locknut 1 Place nozzle in holder 3 Turn adjusting screw to desired opening pressure 2 Tighten nozzle nut finger tight then using proper 4 Tighten locknut to 45 to 50 ft Ib 61 to 68 Nm size wrench tighten nut to 45 to 50 ft Ib 61 to 68 Nm 5 Tighten cap nut to 45 to 50 ft Ib 61 to 68 Nm 3 Connect delivery line between nozzie holder and
106. le opening cycles per second until nozzle ejects a stream of fuel with a soft chattering sound 2 Take pressure readings from gauge 3 Slightly increase hand lever movements 2 or 3 nozzle opening cycles per second the stream velocity should increase and create a hissing sound 4 Accelerate lever movements to 4 to 6 nozzle open ing cycles per second The nozzle should create a shrill whistling sound and a spray pattern SPRAY PATTERN The spray pattern must be compact and well atom ized at full lift to be correct The pressures between nozzle opening and full lift causes the fuel to emerge in a stream change to flag like formations and finally reach atomized spray pattern at full lift with lever movements producing 4 to 6 nozzle opening cycles per second See Figure 69 BLEEDING FUEL SYSTEM Bleed fuel system whenever the filters are changed or when there is air in the lines i Procedure Manually actuate fuel transfer pump until air bubbles are all out and clear fuel flows from the bleed valve automatically Figure 70 If the transfer pump cam lobe is on the high side the priming lever will not operate the pump Rotate the flywheel one revolution before operating the priming iever BLEED VALVE CONNECT FUEL RETURN LINE HERE Flexible Line FIGURE 70 BLEEDING FUEL SYSTEM PREHEATING CIRCUIT This 12 volt battery circuit consists partly of manifold heaters that raise the combustion air temperature
107. le formation by filling the engine cooling system with a 50 50 mixture of antifreeze and water Follow the same service procedures recommended for the captive water side of heat exchangers see previous section to remove rust or scale formations With some keel cooler systems a sea water pump is used for injecting water into the exhaust system Check the water filter after every 100 hours of operation Change sooner if the unit is used under exceptionally dirty water conditions When the boat is dry docked inspect the kee cooler and remove any accumulation of sediment or debris HIGH TEMPERATURE CUT OFF SWITCH A FLEXIBLE HOSE EXHAUST LINE TO MUFFLER FIGURE 17 KEEL COOLER INSTALLATION MARINE WATER PUMPS Two types of marine water pumps are in general use the metal impeller pump and the neoprene impeller pump Each pump has certain advantages and dis advantages see Table 3 and both are used exten sively with marine cooling systems Two types of pumps are necessary because water pumps are used to perform different functions depending onthetype of cooling system and the operating conditions Meta impeller pumps provide no suction lift but can operate in hot cold or dirty water Neoprene impeller pumps provide a suction lift but can be used only with clean cool water The metal impeller pumps are used for captive water systems and the neoprene impeller pumps are used for sea water systems All captive water
108. lets in the blowby fumes to prevent them from getting into the intake manifold and combustion chamber TO INTAKE MANIFOLD OVERFLOW HOSE OIL DRAIN FIGURE 82 PULSATION DAMPER OIL PRESSURE GAUGE Some engines have an oil pressure gauge If faulty replace it Remove with a wrench and install a new gauge Check for a plugged oil passage The nonadjustable oil pressure switch controls the decompression solenoid in the starting system allowing it to energize only when the switch closes This allows the engine to build up speed during start ing before compression occurs The switch closes at about 5 psi 35 kPa under increasing oil pressure This is nota low pressure protec lion switch It will not protect the engine against slowly decreasing oil pressure On MDJA engines if the decompression switch does not energize check switch operation Short the switch to ground when the engine has built up speed during starting The governor solenoid should energize immediately and the engine should start When the engine starts check im mediately for oil pressure Shut the engine down if oil pressure does not build up within a few seconds In this case the lack of oil pressure is causing faulty operation not the switch LOW OIL PRESSURE CUT OFF SWITCH The switch Figure 83 is located on the oil filter adapter plate below the oil filter A special start switch jumpers the cut off switch during startin
109. lting sediment deposits salt silt etc from the engine cooling jacket Both systems have a fixed quantity of captive water in a clased system to cool the engine Sea water cools the captive water in the heat exchanger or keel cooler Sea water and captive water are kept separated so the engine water jacket stays clean Figure 8 shows a typical marine heat exchanger Because marine generator sets operate typically in very small compartments itis important that the heat radiated from the exhaust system be kept to a min imum To accomplish this the heated sea water is usually discharged through the exhaust system Special mufflers pumps and anti siphon devices are required to avoid interference with the passage of exhaust gases and to prevent entry of water into the combustion chamber Direct Cooling System Onan engine generator sets constructed for direct sea water cooling are equipped with a sea water pump and are normally installed with a water filter water inlet valve sea cock and strainer A through the hull flush type fitting is used for a water inlet Heated sea water flows past the thermo stat to the exhaust manifold water cooled and is discharged through the exhaust system The dis charged water cools the entire exhaust system and greatly reduces the amount of heat that would normally radiate from the muffler and exhaust pipe see Figure 9 Although this system is the simplest and has the lowest initial cost it
110. lts in sequence to 44 46 ft Ib 60 62 Nm This step compensates for the compress of the cylinder gasket 6 Install intake manifold nozzles glow plugs and oil lines 7 Install valve stem cap 8 Install push rods rocker arms and rocker arm nuts 9 Set valve clearance See Figure 101 IMPORTANT After the first 50 hours of operation retighten the cylinder head bolts and check valve clearance VALVE ROTATOR CLEARANCE Both the intake and the exhaust valves on all Onan J Series engines are equipped with release type valve rotators The cap covering each valve tip releases keeper tension as the valve is pushed off its seat This allows the valve to float in its guide Engine vibration and cylinder air flow cause the valve to rotate while floating Toassure proper operation of this system valve stem tip to cap clearance should be checked every 5000 hours or whenever the parts are exposed or removed Clearance must be maintained at 0 001 to 0 005 inch 0 025 to 0 127 mm Too little clearance will prevent valve rotation increasing the possibility of valve leakage and engine power loss Too much clearance can lead to valve breakage To check the clearance refer to Figure 104 and pro ceed as follows 1 Remove the cap from the valve tip and measure the depth of the cavity in the cap with a depth micrometer 2 Measurethe valvetip height from the cavity depth to determine the clearance It should be between 0 001 a
111. mounting shim s total thickness or the proper pump gear to camshaft gear mesh will be affected The shim thickness is established at the factory dur ing engine assembly and does not change unless a new cyl nder block is installed Port Closing Formula The procedure for determin ing the proper port closing PC timing button for a new or replacement pump is as follows 1 Remove old pump 2 Determine port closing dimensions and original button thickness from old pump A Write down port closing dimension given on old pump flange and port closing dimension given on new pump flange See example B Use a pair of channel lock pliers or screw driver to remove tappet retaining ring and timing button from old injection pump Figure 48 Use number or letter code on timing but ton to obtain dimension of old timing button from Table 8 This code should be the same as the code number stamped on injection pump Figure 48 Onall PSU pumps be sure to hold the pump drive gear securely against ihe pump body when remov ing the tappet If not the pump will come apart and be difiicultto assemble The meter ing sleeve will drop off the plunger if ihe gear and plunger are removed the plunger port is not closed by the sleeve there will be no fuel delivery and the pump will not operate 4 3 Add dimension on old pump flange to timing but ton dimension See example Example Inches mm Port closing dimension of ol
112. nd 0 005 inch 0 025 and 0 127 mm 3 If the clearance is not within specifications replace the cap and keepers as a set When replacing the keepers check for wear on the valve spring retainer where it contacts the keepers If wear is over 0 003 inch 0 076 mm replace the retainer After replacement of parts recheck the clearance If it is still not within specifications replacethe valve 18 Anytime the valves are to be removed these mea surements should be carried out first Keep each valve assembly together as set When reassembling install the keepers with wear in original position Keepers can be inverted to use the unworn side but the clearance must then be rechecked Place a drop of engine oil on the valve stem before replacing the cap CAVITY DEPTH VALVE TIP HEIGHT TIP TO CAP CLEARANCE NE Ns N FIGURE 104 MEASURING VALVE TIP TO CAP CLEARANCE MDJA DECOMPRESSION RELEASE The decompression release mounts on the cylinder head with a solenoid on the rocker box cover It holds the exhaust valve open to allow the engine to build up speed during starting before compression occurs andto stop engine The mechanism holds the exhaust valve open when the solenoid is de energized If the release is defective replace any worn parts other wise adjust it following the instructions below NOTE Before adjusting the decompression mechanism the valves must be adjusted for the correct clearance Figure
113. nd Play et Nee ee See 005 030 030 760 VALVE INTAKE Stem Diameter Stem is tapered te Oenter cu tuse 3401 3411 8 639 8 664 kit p T 3386 3396 8 601 8 626 Valve Face s sevecriRilezedewsveestaav ae ee Nala DEEMED OM Deer tee ea PME 42 Guide ClearanGe 222225 gb Oe tess Ver rr s bi 0015 003 038 076 VALVE EXHAUST Stem 1 eme rete ne Ee de emis Se 3405 3415 8 649 8 674 Guide Clearance viis colo sed pv PEEN S S Wa REIR EXE TR AREE URS ETE T 0030 0050 076 127 Valve FaCces pra EIQUE ee e eu eee REIR DER iV e Sa Sim M ra Mog s 45 VALVE GUIDE Leng ooi orae Ex EE Ex pete SE vu POT Lex CPP AA TEUER US UE EUR 1 7812 45 2424 Outside Diameter 0 cece cece eens EEEO NAS 4690 4695 11 9126 11 9253 Inside Diameter after reaming Exhaust oet ove sein a rk EIS RIEN E PRI a Ros ete a ar d 3445 3455 8 750 8 776 In ERRORES TIE 3425 3435 8 700 8 725 Cylinder Block Bore 467 468 11 8618 11 8872 VALVE SEATS Valve Seat Bore Diameter e tex odie Fass Ue e elo qu Mis We 1 547 1 548 39 29 39 32 EXHAUST ccc urbs sa ae seaweeds sitet cans red
114. ner should never contact vaive stem seal when valve springs are being compressed to install spring retainer locks IMPORTANT Units built before June 1962 had no valve seals 2 Oil stem of each valve lightly and insert each in its own guide 3 Check each valve for a tight seat with an air pressure type tester If a tester is not available make pencil marks at intervals on valve face observe if marks rub off uniformly when valve is rotated part of a turn in seat If seat is not tight regrind valves 4 Using valve spring compressor compress each valve spring and insert valve spring retainer and retainer locks 5 Install head assembly and gasket to cylinder block Tighten head bolts to 44 to 46 ft Ib 60 62 Nm Follow sequence in Figure 103 and Steps A through C FIGURE 103 HEAD BOLT TORQUE SEQUENCE Use Never Seez Fel Pro C5 A or equivalent thread lubricant when installing cylinder heat boits A Tighten cylinder head bolts finger tight B Install exhaust manifold and tighten four cylinder models only Installing manifold now aligns all four exhaust ports with the exhaust manifold before the heads are torqued down Add exhaust manifold lock tabs to prevent manifold nuts from coming loose C Tighten cylinder head bolts in sequence shown in Figure 103 to 25 30 ft Ib 34 41 Nm Tighten cylinder head bolts in same sequence to 44 46 ft lb 60 62 Nm E After 60 seconds retighten cylinder head bo
115. ng system Keel Cooling System Or Skin Cooling Keel coolers are comprised of aseries of finned tubes through which heated engine coolant is circulated The keel cooler is attached to the underside of the boat keel so that flotation water can pass between the fins the heat from the engine coolant is trans ferred to the finned tubes and absorbed by the flotation water Keel coolers function similar to radiators except that the heat is dissipated to the flotation water instead of to the air An engine driven pump is used to circulate the coolant through the water jacket and cylinder heads to the keel cooler 19 second pump is sometimes used to draw flotation water and discharge it through the exhaust system This cools the muffler and exhaust pipe and reduces the amount of heat radiated from these components As with heat exchanger systems the sea water is never mixed with the engine coolant Figure 11 shows a schematic of a keel cooler system Skin coolers function similar to keel coolers except that a section of the hull with an extra skin is used to dissipate the heat Engine coolant passes between the hull of the boat and the exterior skin The heat is transferred to the skin and absorbed by the flotation water The remainder of the system operates the same as a keel cooler system Keel coolers must be designed to provide adequate cooling when the water flowing through the fins is ata minimum and the temperature of the flot
116. ng your little finger Install spring and valve holder If the spring is not seated prop erly the valve holder can be tightened only about one fourth of the way down When the spring is properly seated the valve holder can be tightened about three fourths of the way down by hand Make certain that the spring is seated properly in the valve holder and on the delivery valve before torquing Torque valve holder to 70 to 75 ft Ib 95 to 102 Nm Loosen valve holder and retorque to 65 to 70 ft Ib 88 to 95 Nm Install and torque capnut with gasket to 50 to 55 ft Ib 70 to 75 Nm Loosen capnut and retorque to 60 to 65 ft Ib 81 to 88 Nm INJECTION PUMP INSTALLATION Be sure the steel shims between the pump and the cylinder block mounting are the same These shims maintain proper gear backlash The number stamped on the cylinder block injection pump mounting pad indicates the proper shim thickness This thickness does not change when a new pump is installed It changes only when a new cylinder block is installed 1 Turn engine in direction of rotation clockwise when viewed from the front of engine until number one cylinder is on a compression stroke and the PC mark on flywheel lines up with timing pointer on gearcase Figure 52 Rotation clock wise also takes out all gear backlash in that direction Look into injection pump mounting hole to verify that one intake lobe points outward and down 45 degrees 2 Remove screw
117. nhalation of exhaust gases might result in serious personal injury or death Inspect exhaust system audibly and visually for leaks daily Repair any leaks immediately WATER COOLED EXHAUST Marine exhaust systems are designed so that a minimum mount of heat will be radiated from the exhaust system components This is done to keep the heat build up in the engine compartment to a min imum Exhaust heat is dissipated by using a water cooled exhaust manifold and a water injected exhaust pipe and muffler system The exhaust manifold is encased ina shell through which engine coolant or sea water is circulated Just beyond the exhaust manifold a special elbow see Figure 4 is fitted which allows the output water from the sea water system to be injected into the exhaust pipe The injected sea water is carried out thorugh the exhaust system and discharged into the flotation water CONNECTED TO EXHAUST MANIFOLD SEA WATER INPUT EXHAUST ELBOW APPLY PIPE SEALANT ASSEMBLY HIGH EXHAUST TEMPERATURE RUBBER SHUTDOWN SWITCH EXHAUST HOSE EXS 1014 FIGURE 4 EXHAUST ELBOW Typical installations All water injected exhaust systems must be designed so that the discharge water will not flow back into the engine There are several methods that can be used to keep water out of the engine All are based on injecting the water at a point a few inches approx imately 4 inches 102 mm below the exhaust mani fold outlet and installing a sharp dr
118. ns check for the correctness of ring and bore sizes A cylinder bore that is 0 001 inch 0 03 mm under size will reduce the end gap 0 003 inch 0 08 mm If oversize pistons are used use the correct oversize rings CONNECTING RODS Clean the connecting rods and check each for de fects Check the connecting rod bushings for proper clearance with the piston pin Clearance should be 0 0002 to 0 0007 inch 0 0051 to 0 0178 mm If the bushings are excessively worn press them out and install one new bushing from each side of the bushing bore Press the new bushings only until flush with the sides of the rod to leave 1 16 to 7 64 inch 1 588 to 2 776 mm oil groove in the center See Figure 110 CONNECTING ROD BEARINGS Inspectthe connecting rod bearings for burrs breaks pitts and wear Measure the clearance between bear ings and the crankshaft journal The clearance should be 0 001 to 0 003 inch 0 0254 to 0 076 mm If neces sary replace with new standard or oversize precision bearings CONNECTING ROD BUSHINGS BUSHING ENDS MUST FLUSH WITH SIDES OF ROD TO PERMIT 1 16 OIL GROOVE BETWEEN BUSHINGS PRECISION TYPE BEARING a CROSS SECTION MEASURE CLEARANCE IN DIRECTION INDICATED BY ARROW ABBI Rev FIGURE 110 CONNECTING ROD BUSHINGS ASSEMBLY AND INSTALLATION 1 Instali connecting rods on each piston with pins and retaining rings If new bushings were in stalled check to see that ends are
119. ntil the shaft can be rotated freely by hand without binding The pump must be adjusted with the drive belt off If not centered properly the impeller will rub on the body or cover and quickly overheat Clearance A may vary from zero to 1 16 inch 1 6 mm Tighten lock screw when adjustment is correct being careful not to alter setting When the pump is reinstalled on the engine check to see that the pump pulley is aligned with the crank shaft pulley and adjust as required 26 WATER PUMP 131 0152 Water pump 1131 0152 is a neoprene impeller type pump Figure 21 Disassembly 1 Remove the pump end plate screws end plate and gasket as shown in Figure 21 step a 2 Pull out neoprene impeller with a pair of pliers Step b 3 If further disassembly is required disconnect the hoses and remove the two cap screws holding the pump to the engine Step c Lift pump from engine 4 Loosen the set screw on the side of the pump and tap it lightly to free the cam from the pump body Lift out cam and wear plate Step d 5 Remove the retaining ring using a screwdriver as shown in Step e and slide the seat assembly O ring and ceramic seal off the pump shaft 6 Pry the bellows assembly out of the pump body by inserting a screwdriver through the drain slots Step f 7 Drive the shaft and bearing assembly out of the pump body using a bearing driver or press The bearing is press fit on the shaft and comes off in one
120. ny piston is badly scored or burred loose in the cylinder has badly worn ring grooves or otherwise is not in good condition replace it See Figure 109 Install pistons with valve relief recess facing the camshaft side of engine to match valve positions Check the clearances 90 degrees from the axis of the piston pin and below the oil control ring Clearance should be 0 005 to 0 007 inch 0 127 to 0 178 mm If not replace the piston and check the cylinder for possible reconditioning PISTON PINS Each piston pin should be a thumb push fit into its piston at room temperatures If the pin is excessively loose install a new one If the condition is not cor rected install the next oversize pin If the piston is worn enough so that the oversize pin will not fit replace it CAST IRON OIL CONTROL RING GUIDE PIN IN POSITION INSTALL WITH VENTS AT BOTTOM AWAY FROM CLOSED END OF PISTON RINGS PISTON CHROME COMPRESSI ON PLAIN COMPRESSION EXPANDER A887 VENTS FIGURE 109 PISTON RINGS RINGS Inspect each ring carefully for fit in the piston grooves and for seating on the cylinder wail Fit each ring to the cylinder wall at the bottom of its travel using a piston to square the ring in the bore Check the gap with a feeler gauge It should be 0 010 to 0 020 inch 0 254 to 0 0508 mm The practice of filing ring ends to increase the end gap is not recommended If the ring end gap does not meet specificatio
121. ocker arm pin hole and drive in pin The priming lever must be in position shown in Figure30 when installing rocker arm 3 Compress rocker spring and install between the body and rocker arm 4 Assemble cover to body with notch marks lined up Install screws but do not tighten WARNING Fuel leakage is a fire and explo sion hazard that might cause severe personal injury or death Use care when reassembling fuel pump All parts must align per fectly or pump will leak fuel 5 Push rocker arm in one full stroke and hold in this position to flex diaphragm 6 Tighten cover screws alternately and securely then release rocker arm 7 Install pump on the engine and repeat pressure test INJECTION NOZZLES Onan diesel engines use hydraulically operated pintle type injection nozzles Figure 31 They are fac tory adjusted to open at 1900 to 1950 psi 13 110 to 13 455 kPa However after several hundred hours of operation the nozzle pressure will decrease to about 1750 psi 12 075 kPa Refer to the throttling pintle type nozzle information at the end of this section for information regarding MDJE engines using Bryce Kiki fuel systems NOZZLE GASKET COPPER NOZZLE SHIELDS SHIELD GASKET FUEL CUP GASKET _ NOZZLE ASSEMBLY CYLINDER HEAD A880 1 FIGURE 31 INJECTOR NOZZLE ASSEMBLY INSTALLATION Operating Principle Nozzle operation is as follows 1 High pressure fuel from the injecti
122. on of the dimple facing up Coat the top of the cam and cam set screw threads with sealer Line up the dimple inthe wear plate with the hole in the cam and then tighten the Set screw Slide the impeller over the shaft and secure with the impeller pin Lubricate the shaft with grease Check shaft to make sure it is free of burrs Lubricate the impeller bore with grease and then install the shaft and impeller assembly Use a twisting motion when fitting the impeller into the impeller bore Hold the new end cover gasket against the pump housing and install the end cover securing it with three screws Mount the assembled pump on the engine and attach the hoses COOLING SYSTEM HOSES Leakage is the most common cooling system trouble Besides losing coolant leaks may also admit air This can result in premature failure of the water pump impeller Testall hoses by squeezing and replace any that have become cracked and brittle or overly soft Verify that all clamps and connections are tight and check for leakage White rusty or colored stains indicate points of previous leakage With the generator set running observe the water that is discharged from the exhaust outlet The presence of air bubbles indicates that air is being admitted into the sea water system Tighten all hose connections as required Cannot be observed if Aqualift muffler is used EXHAUST SYSTEM HOSES Inspect all exhaust system ho
123. on pump enters the fuel inlet stud and flows down drilled pas sages in the body of nozzle holder Figure 32 2 Fuel enters fuel duct and pressure chamber of nozzle assembly When fuel pressure overcomes preset pressure of the adjusting spring the pintle is forced upward off its seat and a fine mist of fuel is injected into the pre combustion chamber where the vaporized fuel mixes with the hot com pressed air 3 If compression temperatures are high enough the fuel air mixture ignites Injection continues until the spill port clears the top of the metering sleeve in the injection pump and dumps the high pressure fuel into the sump allowing the pres sure spring to close the injector and cut off fuel injection to the cylinder Do not disturb the injector pressure adjusting screw it cannot be reset without proper equipment Bypass fuel is returned to the tank after each injection Cycle by a return line from the nozzle A fuel return fitting combines the return fuel from the injectors with the flow through fuel from the injection pump bleed valve A return line connected at this point returns the combined fuel to the fuel supply tank COVER PRESSURE ADJUSTING SPRING SCREW FUEL INLET SPINDLE ASSEMBLY ADAPTER VALVE SEAT PINTLE FIGURE 32 INJECTOR NOZZLE AND HOLDER ASSEMBLY Nozzle Spray Pattern A nozzle suspected of misfiring can be checked in the field by removing it from the engine and reconnecting it to
124. op in the exhaust line that water cannot normally flow over These methods are divided into two general categories above water line and below water line installation Above Water Line The exhaust manifold must be one foot or more above the load water line and the water must be injected near the exhaust manifold The exhaust pipe is pitched downward 1 2 inch per foot 13 mm per 305 mm to allow draining in the line whether the genertor set is running or stopped Below Water Line An Onan Aqualift muffler may be used for below the water line installations if the lift height is no greater than four feet 1220 mm A siphon break is required when the water injection elbow is below the water line see Figure 5 to prevent water from being siphoned into the exhaust manifold The siphon break will be mounted at least 12 inches 305 mm above the load water line If the tift height is greater than four feet 1220 mm a riser exhaust system will be used The exhaust system will run in a loop above the water line to a point 12 to 18 inches 305 to 457 mm above the boat load water line A water jacket encloses the loop and the water is injected on the outlet side at a point four inches 102 mm above the bottom of the loop A condensation trap is usually installed atthe bottom of the dry exhaust line seciton Drain the trap at regular intervals to remove condensation Generally exhaust systems should be as short as possible with a minimum num
125. ough a loose cylinder head joint worn water pump shaft seal or a cracked or porous cast ing The feakage is not visible but can cause extensive damage to the engine The coolant mixes with the oil to form sludge which causes lubrication failure Heavy sludge accumulations followed by sticking piston rings valves and valve lifters are symptoms of internal leakage Sometimes internal leaks are tight enough to prevent coolant leakage but permit exhaust gases to enter the cooling system The exhaust gases dissolve in the coolant depleting the rust inhibitors and forming acid which causes corrosion A leaking water pump shaft seal can allow water to enter the crankcase on J series engines with water pump 132 0147 Refer to WATER PUMP REPAIR section for pump repair procedure DRIVE BELTS A V belt is used to drive all captive water system pumps Belt tension is adjusted by changing the posi tion of the pump Inspect the belt periodically and replace if worn or glazed Also check to see if the pulleys are properly aligned and if the belt tension is sufficient To adjust the belt remove the belt guard and loosen the water pump mounting bolts Slide the pump back and forth in the mounting base slots until the correct belt tension is obtained There should be a 1 2 inch 12 7 mm deflection when a 15 Ib 67 N force is applied at the midpoint of the belt Tighten the mount ing bolts when the correct tension is reached and reinstall th
126. ould be 25 psi 172 5 kPa or higher when the engine is at operating temperature If pressure drops below 20 psi 138 kPa at governed speed inspect the oil system for faulty components OIL PUMP The oil pump is mounted on the front of the crank case behind the gear cover and is driven by the crankshaft gear The pump draws oil from the crankcase and delivers itthrough the oil filter to the rocker housing through the crankcase drillings to the crankshaft bearings camshaft front bearing crankshaft passages to con necting rod bearings and connecting rod passages to piston pin bushings Removal 1 Remove gear cover and oil base See ENGINE DISASSEMBLY 2 Unscrew intake cup from pump 3 Remove crankshaft lock ring and gear retaining washer 4 Loosentwo capscrews holding pump and remove pump BY PASS VALVE Q LS 1013 FIGURE 75 OIL PRESSURE SYSTEM Repair Except for the gaskets component parts of the pump are not individually available If the pump is defective or excessively worn replace it Disassemble the pump by removing the two capscrews holding the pump cover to the body Inspect for excessive wear in gears and shafts To improve pump performance adjustthe gear end clearance by changing the gasket thickness between the pump body and cover Use the thinnest gasket that permits free movement of the pump shafts Oil all parts when assembling the pump Installation Before installing
127. out the shaft seal from the pump body by forcing it toward the impeller bore 8 Remove the O ring seal spacer and slinger from the impeller bore Assembly Inspect the pump housing for wear rough surfaces or pitting and replace if any of these conditions exist 30 Replace any other worn components such as bear ings seal seal seat and impeller Use anew end plate gasket when reassembling 1 Press the bearing seal into the bearing bore with the lip towards the bearing side 2 Insert the impeller end of the shaft into the drive end of the pump housing and press the shaft and bearing assembly into the bearing bore 3 Press the adapter ring into the drive end of the pump body 4 Install the slinger on the shaft and place the seal spacer in the seal cavity 5 Install the O ring in the seal bore and press the seal into the seal bore with the lip toward the impeller side 6 Coat the top of the cam and the cam set screw threads with sealer and install the wear plate and cam assembly Be sure that the cam is flush with the end cover before tightening the set screw 7 Lubricate the impeller bore with grease and install the impeller and spline seal 8 Lubricate the impeller face with grease Hold the new end cover gasket against the pump housing and install the end cover securing it with six screws 9 Mount the assembled pump on the engine and attach the hoses FLANGE PUMP BODY cing seat IMPELLER SIDE
128. ow Full Flow Crankcase Capacity qt 3 35 6 5 3 5 65 with filter change litre 2 8 3 3 6 2 3 3 6 2 Dimensions and Clearances All clearances given at room temperature of 70 F 21 C All dimensions in inches millimeters in parentheses unless otherwise specified CAMSHAFT Bearing Journal Diameter Front 2 2500 2 2505 57 150 57 163 Bearing Journal Diameter Center 4 1 2580 1 2582 31 953 31 958 Bearing Journal Diameter Rear 1 1875 1 1880 30 163 30 175 Bearing Clearance Limit Original 2 ce eee cece cece 0015 0030 038 076 Bearing Clearance Limit Replacement 0012 0049 030 123 End Play iios edhe e RET yes Ce o ees re 007 039 0 2 1 0 Cam Tappet Diameter Prior to Spec P 7475 7480 18 987 18 999 Cam Tappet Hole Diameter Prior to Spec P 7507 7515 19 068 19 088 Cam Tappet Diameter Begin Spec 8725 8730 22 162 22 174 Cam Tappet Hole Diameter Begin Spec P Du pU e Ps 8755 8765 22 238 22 263 CONNECTING RODS Large Bore Diameter eer he tre rt Re err vr 2 1871 2 1876 55 5523 55 5650 Small Bore Diameter deese Sas doe
129. p pin to mounting face of cover It should be 25 32 inch 19 844 mm If itis not replace pin Pin should be positioned with open end facing crankshaft seal 4 Coat oil seal lip with oil or grease Set a piece of shim stock over the crankshaft keyway to protect seal and install gear cover Tighten mounting screws to 15 to 20 ft Ib 20 to 27 Nm Before tightening screws be sure the stop pin is in gov ernor hole WHEN GOVERNOR IS PROPERLY ASSEMBLED THE DIMENSION SHOWN ON DRAWING WILL BE AS INDICATED GOVERNOR GOVERNOR ARM GOVERNOR SHAFT YOKE Smooth side toward cup m fy POSITION P 5 GOVERNOR cup Pm A SOTHAT e Q ROLL PIN a FITS INTO 24 HOLE IN CUP GOVERNOR IF FEELER WILL 3 ENTER HOLE 1 2 BALL HAS FALLEN OUT BE SURE THAT OIL PASSAGES ARE OPEN B343 FIGURE 106 GEAR COVER ASS MBLY GOVERNOR CUP To remove the governor cup remove the snap ring GEAR COVER from the camshaft center pin and slide the cup off Be sure to catch the ten flyballs that will fall out when the cup is removed Figure 108 shows the governor cup INSTALL OIL SEAL FLUSH WITH THIS Repair SURFACE Replace any flyballs that have flat spots or grooves Replace the cup if the race surface is grooved or OIL SEAL rough The governor cup must be a free spinning fit on the camshaft center pin but should be replaced if excessively loose or wobbly The
130. perations To flush heat exchanger 1 Flush the engine water jacket as previously dis cussed 2 First remove water outlet hose between engine water jacket to the heat exchanger 3 Flush both fresh water side and raw water side of heat exchanger 17 4 Remove rubber impeller pump cover to flush raw water side 5 Flush the water cooled exhaust manifold 6 When flushing is completed check the system thoroughly for leaks FILLING COOLING SYSTEM All closed or captive water cooling systems should be filled with 50 50 mixture of antifreeze and clean water This is the amount recommended for satisfac tory corrosion protection and boil over protection In extremely low temperatures 25 F or lower it may be necessary to increase the percentage of antifreeze to provide adequate protection against freezing Follow the recommendation of the supplier to determine the amount of antifreeze needed for the lowesttemperature expected The antifreeze solution must be able to protect the cooling system during the coldest winter weather Table 1 shows the capacities of the various cooling systems TABLE 1 COOLING SYSTEM CAPACTIES CAPACITY IN QUARTS UNIT ENGINE AND HEAT EXCH 2 3 2 L 4 5 4 3 L 9 5 9 L 4 5 4 3 L 9 5 9 L Heat Exchanger Filling Improper filling of the heat exchanger Figure 7 can cause overheating ofthe engine To preventthis pos sibility follow these instructions whenever adding coolant
131. point to previous neglect of oil changes If journal dimensions are not within limits or the journals are scored regrind the crankshaft Crankshaft Grinding Crankshaft grinding requires a trained experienced operator working with precision equipment Procedures which may be satisfactory for some spark ignition engines may well be unsatisfac tory for diesel applications resulting in expensive failures Special procedures must be observed when rework ing diesel crankshafts In addition to machining the crankshaft must be shot peened and super finished Failure to shot peen the crankpin fillets is likely to cause early failure When the shaft is machined fol low the directions and dimensions given in Figure 116 to shot peen each crankpin fillet 3 16 4 763 mm THESE SURFACES TO BE SHOT PEENED 15 16 23 81 3 mm THIS AREA TO BE MASKED DURING SHOT PEENING OPERATION FIGURE 116 SHOT PEENING THE CRANKSHAFT 1 Almen gauge reading 0 012 A 0 305 2 Peen with 0 019 inch 0 482 mm diameter cast Steel shot 3 Peen for 30 seconds on each crankpin fillet 4 Mask off connecting rod bearing areas Undersize bearings and connecting rods are availa ble to rework the shaft to 0 010 inch 0 254 mm 0 020 inch 0 508 mm and 0 030 inch 0 762 mm undersize Main Bearings Replace main bearings if clearances are greater than limits or if the bearings are worn grooved or broken Precision replacemen
132. port closing dimension stamped on the pump mounting flange The port clos ing dimension is measured at the factory using a number 11 or standard button Pump timing is critical use one of the two timing methods to determine correct new button thickness If the correct button is not supplied with the replace ment pump refer to Table 8 and order the correct one from your Onan dealer TABLE 8 TIMING BUTTONS 147 0186 147 0147 147 0187 147 0148 147 0188 3 147 0149 147 0189 147 0150 147 0190 147 0151 TiorStd 147 0161 147 0152 147 0153 147 0154 147 0155 147 0156 46 TIMING PSU OR MODEL 50 INJECTION PUMPS One of two methods can be used to determine the proper timing button to time the fuel injection pump correctly to the engine Method 1 Timing by Calculation This procedure is used when dimensions are available for replacing an old pump before the pump is installed Timing by calculation requires the port closing dimension and button thickness from the pump being replaced It also requires the port closing dimension of the new pump Put the dimensions in the PORT CLOSING FORMULA and calculate the new button thickness After determining the timing button thickness find the button code in Table 8 If injection pump is removed from the engine make sure the steel shims between pump and cylinder block mounting remain the same These shims main tain proper gear backlash Do not change the pump
133. r head Valves springs rocker arms Camshaft and gear rear bearing plate oil pump 11 Piston connecting rod bearings 12 Crankshaft 13 Try to analyze reasons for any parts failure and necessity of the repair Cleanliness and neat orderly work area makes job easier to do Use proper meters and gauges Observe if cylinder requires boring crankshaft needs grind ing or if other major shop work is necessary ci 4 14 15 Assembly Use Genuine Onan Parts 1 Engine assembly procedure is normally the reverse of disassembly observing proper clearances of bearings connecting rod proper fitting and sizing of piston rings etc 2 Follow proper recommended procedure for fit of valves adjusting clearances and torque of all special items Use a torque wrench to assure proper tightness without danger of stripping threads 3 As each internal engine part is assembled use a wrench to rotate crankshaft making certain it turns freely If tightness is noted after any opera tion you then know your last step is responsible 15 4 As each internal engine part is assembled coat it heavily with oil same grade used in crankcase During first few critical moments of operation the engine will depend on this lubrication 5 Afteryouhaveinternal engine parts reassembled the engine should turn freely If reasonable care and attention have been given the engine will operate efficiently 6 A
134. rd the front of the engine to full fuel range The fuel solenoid must be energized or held blocked to keep the plunger out of the way 5 Manually operate transfer pump lever to provide fuel pressure to injection pump 6 Rotate flywheel clockwise very slowly by hand until fuel stops flowing from open line even though transfer pump operation is continued 7 Rotate flywheel counterclockwise until fuel flows freely then clockwise very slowly to position where fuel drops can be counted at one drop per second with the transfer pump operating This is the PC point it should be marked on the flywheel opposite the timing pointer 8 After flow timing is completed remove high pres sure line and delivery valve holder then reinstall delivery valve spring and volume reducer Make sure all parts are clean 9 Reinstall delivery valve holder and torque Bryce holder to 29 to 33 ft Ib 39 to 44 Nm Torque Kiki holder to 44 to 47 ft Ib 60 64 Nm If fuel leakage occurs replacethe delivery valve gasket 10 Reinstall high pressure line between pump and nozzle 11 Using the same procedure flow timing can be performed on the other cylinder to determine PC or the difference in degrees between cylinders 2 5 degrees is allowable Engine Performance Engine performance at 1500 and 1800 rpm varies within acceptable limits when PC occurs between 14 and 22 BTC Generally retarded timing results in lower smoke but hi
135. re without a testing fixture Disassembly When removing and disassembling nozzles separate and label all components of each nozzle Never interchange components between nozzles 39 1 Remove each nozzle assembly from engine and remove fuel inlet and return lines 2 Clamp nozzle holder body in a vise and remove nozzle cap nut and nozzle 3 Install nozzle cap nut loosely to protect lapped surface of the holder body 4 f necessary to disassemble nozzle further reverse pressure adjusting screw and lift out spring and spindle assembly Do not attempt io disassemble the nozzles or adjust nozzle pressure without the proper test equipment A nozzle pressure tester is essential to do a satisfactory job The cleaning procedure Figure 35 is extremely important when disassembling injection equipment Always rinse in clean fuel before reassembling Injection Nozzle Tester Testing and adjustment can be performed only with a nozzle tester Figure 34 Do not attempt to disassem ble the nozzles or adjust nozzle pressure without the proper test equipment Opening pressure leakage and spray pattern can be checked using the tester If any of the above condi tions appear except opening pressure inspect the nozzle valve and seat with a magnifying glass for erosion scoring etc If cleaning with solvent does not correct the condition a new nozzle tip will be required The opening pressure can then be set and spray pa
136. res below 32 F 0 C Number 2 D fuel may pose operating problems At colder tempera tures use Number 1 D fuel if available or use a winterized Number2 D a blend of Number 1 D and Number 2 D The blended fuel is normally called Number 2 D also but can beused in colder tempera tures than non winterized Number 2 D fuel Do not add gasoline gasohol or alcohol to diesel fuel Damage to fuel injection system or engine may result NOTE Fuels with Cetane numbers higher than 45 may be needed in higher altitudes or when extremely low ambient temperatures are encountered to prevent misfires and resultant excessive smoke Use low sulfur content fuel having a cloud point of at least 10 degrees below the lowest expected fuel temperature Cloud point is the temperature at which wax crystals begin to form in diesel fuel Spilled fuel might ignite and cause serious personal injury or death Never fill the fuel tank when the engine is running 36 Fuel leaks create fire and explosion hazards which might result in severe personal injury or death Always use a length of flexi ble tubing between engine and the fuel supply line to avoid line failure and leaks due to vibration The fuel system must meet applicable codes FUEL SYSTEM The fuel system consists of a sediment bowl fuel transfer pump primary filter secondary filter injec tion pump injectors and the connecting fuel lines The fuel system located on the serv
137. rt yoke and shaft assembly for installing the retaining ring T Using hollow end of bearing driver press retain ing ring on shaft far enough so ring snaps into groove on shaft 8 Slide bearing spacer sleeve shortest sleeve over hollow end of bearing driver then use tool to press top bearing into adapter Make sure tool bottoms against top of adapter boss and that let tered side of the bearing faces upward 9 Replace bearing spacer sleeve with seal spacer sleeve longest sleeve and then use tool to press oil seal over shaft at top of adapter Make sure seal is installed with lettered side down facing the bearing and that tool bottoms against top of adapter boss 10 Reinstall adapter and injection pump assemblies GASKET ADAPTER DEPTH MICROME TER CYLINDER BLOCK WALL FIGURE 63 MEASURING DEPTH FOR SHIM THICKNESS Installation Proceed as follows 1 Place new gasket on engine block dowel pins and install adapter using four socket head screws and lock washers torque screws to 20 to 24 ft Ib 27 to 33 Nm 2 Determine shim thickness required between pump and adapter because the new gasket may not be the same thickness as the original one See Figure 63 The proper shim thickness is stamped on the block for the shim combination required during the original factory instal lation of the injection pump 3 To measure for shim thickness A Rotate crankshaft to position injection pump
138. ructions if the muffler does not func tion properly 39 All mufflers must be well supported and in the case of a neoprene muffler completely separated from the hull of the boat If a neoprene muffler touches the vessel it increases exhaust noise wanNiNG Do notuse the manifold as a muffler support because it puts excessive strain on the connecting exhaust line and can cause it to break or leak resulting in the escape of deadly exhaust gases Fuel System FUEL RECOMMENDATIONS Fill the fuel tank with a good quality fuel obtained from a reputable supplier The quality of fuel used is important in obtaining dependable performance and satisfactory engine life Fuels must be clean com pletely distilled well refined and non corrosive to fuel system parts Fuel vapors create fire and explo sion hazards which might result in severe personal injury or death Do not add gasoline gasohol or alcohol to diesel fuel Do not permit any flame cigarette or other igniter near the fuel system Due to the precise tolerances of die sel injection systems it is extremely important the fuel be kept clean and free of water Dirt or water in the system can cause severe damage to both the injection pump and ihe injection nozzles Use ASTM2 D No 2 Diesel or ASTM1 D No 1 Diesel fuel with a minimum Cetane number of 45 Number 2 diesel fuel gives the best economy and performance under most operating conditions At temperatu
139. s baie eee ere bein bie RR Ere wie dole 1 043 1 045 26 4922 26 543 Large Bearing Bore to Small Bearing Bore Center to Center sen a ees er a i ers es 5 998 6 002 152 3492 152 4508 Connecting Rod End Play 2 eee cece eee reece eee cece HH hh hs nn 002 016 05 41 CYLINDER Bore Honed Diameter MDJB 3 2495 3 2505 82 537 82 563 Bore Honed Diameter 3 4995 3 5005 88 887 88 913 Maximum Allowable Taper hh hh nnn 0 005 0 127 Maximum Allowable Out of Round e nce c eee e cere eh he hh nnn 0 001 0 025 CRANKSHAFT Main Bearing Journal Diameter 1 amp 2 cylinder 2 2431 2 2445 56 99 57 01 Main Bearing Journal Diameter 4 2 2427 2 2435 56 965 56 985 Center Main Bearing Clearance 4 cylinder 0024 0052 061 132 Front and Rear Main Bearing Clearance Original 4 0030 0043 076 109 Front and Rear Main Bearing Clearance Replacement 4 0024 0062 06 16 Main Bearing Clearance Original 1 amp 2 cylinder 002 0033 051 084 Main Bearing Clearance Replacement 1 amp 2
140. ses for leaks and replace any hoses that are cracked and brittle or overly soft Rubber hose should be used only in the water cooled sections of the exhaust When replacing use only rubber hose designed and approved for marine exhaust use Provide adequate support for rubber hose to prevent sagging bending and form ation of water pockets Automotive type tail pipe hangers should be used to prevent vibration from being transmitted to the hull Use two hose clamps having a minimum width of 1 2 inch 12 7 mm at each end of the hose Inhalation of exhaust gases might result in serious personal injury or death Do not make any sharp bends in rubber exhaust hose when installing as it might cause hose fallure and gas leakage The exhaust line should be at least as large as the engine exhaust outlet and increased one pipe size for each ten feet of length Inhalation of exhaust gases might result in serious personal injury or death Pipe exhaust outside the hull and do NOT terminate exhaust pipe near any window or bulkhead door openings ENGINE WATER JACKET AND CYLINDER HEAD External coolant leakage may occur at any of the joints in the engine water jacket such as the drain plugs core hole plugs or cylinder head joints Since expansion or contraction can aggravate leakage the block should be inspected both hot and cold while the engine is running 32 Internal leakage occurs when coolant passes into the engine oil thr
141. shing in the end plate may be removed by drilling Do not drill through the end of the cover plate Assembly Inspect the pump housing for wear rough surfaces or pitting and replace if any of these conditions exist Replace any other worn components such as bear ings bushings seal seal seat and impeller Use a new end plate gasket when reassembling A new bushing may be pressed into the end plate after cleaning Pump assembly is the reverse of disas sembly ge ze e IMPELLER 7 END PLATE END PLATE GASKET a 27 SET SCREW WEAR PLATE dE bon ADAPTER RING SNAP a RING 27 BEARING m ay BEARING SEAL 6 BEARINGS PUMP HOUSING FIGURE 24 PUMPS 132 0146 AND 1132 0147 WATER PUMPS 132 0146 and 132 0147 Water pumps 132 0146 and 132 0147 are neoprene impeller type pumps see Figure 24 Disassembly 1 Remove the pump end plate screws end plate and gasket 2 Pull out the neoprene impeller with a pair of pli ers being careful not to damage the pump body 3 If further disassembly is necessary disconnect the hoses and remove the cap screws holding the pump to the engine Lift pump from engine 4 Force out the shaft assembly and adapter ring from the pump body by pressing on the impeller end of the shaft 5 Remove the set screw from the side of the pump and lift out the cam and wear plate 6 Carefully pry the bearing seal out of the bearing bore using a screwdriver 7 Press
142. sket in cylinder head recess 2 Install heat shield heat shield gasket second heat shield and nozzle gasket 3 Insert nozzle assembly into recess Do not strike tip against any hard surface 4 Install nozzle flange and two capscrews Tighten capscrews alternately to avoid cocking nozzle assembly Tighten each to 20 21 ft Ib 27 28 Nm FUEL SOLENOID The fuel shutoff solenoid Figure 36 is also referred to as a governor solenoid as it over rides the gover nor during shutdown The solenoid is mounted on a bracket and controls the injection pump operating lever When energized the plunger pulls into the solenoid body When de energized the solenoid spring forces the plunger out against the operating lever to hold it in the fuel shutoff position The solenoid has two coils Both are energized for pulling the plunger up When the plunger reaches the top it opens a set of contacts de energizing the pull in coil The other coil holds the plunger up while the engine is running and de energizes when the engine shuts down 4 SOLENOID WIRE TO CONTROL GOVERNOR ARM FUEL RETURN FITTING CONTAINS BLEED PL VALVE UNGER AND SPRING RETAINER GOVERNOR LINKAGE ADJUSTMENT SCREW AND JAM NUT INJECTION PUMP DELIVERY VALVE CAPSCREW FIGURE 36 FUEL SOLENOID To test the solenoid check plunger operation and current draw with 12 volt input Current draw with the plunger up should be about 1 amp J
143. ssembly the bearing surfaces in the gear case and breaker plate and the oil trickle holes to these bearings Check the oil spray hole in the gear case to be sure it is open Check for wear in the spacer fiber plunger and the spring loaded shaft plunger The spacer must be at least 0 35 inch 8 89 mm long If it is not replace it immediately Push the weights outward they should move freely If they do not or if any part of the assem bly is sticking or worn replace the cam and weight assembly if the cam is loose on the gear shaft replace the assembly If the breaker gap cannot be maintained at 020 inch 0 51 mm check the fiber plunger and spacer for wear Assembly 1 Install the spacer on the shaft and install the shaft assembly into the gear case Match it with the cam gear 2 Install the spring and plunger into the end of the shaft 3 Install the breaker plate 4 Install the plunger and diaphragm 5 Install the breaker points on the breaker plate and set the gap at 0 020 inch 0 51 mm 6 install the switch cover and reconnect the battery 67 Starting System These models use a separate 12 volt starting motor mounted on the right hand side of the engine to drive the flywheel It is a standard automotive starting motor with a solenoid for engaging the pinion and an over running clutch When the solenoid is energized its core pulls in shifting the pinion into engagement with the flywheel ring gear
144. system pumps metal impeller are driven by a V belt from the engine crankchaft All sea water pumps neo prene impeller for the J series except MDJE Spec AB are gear driven Captive Water Pump Periodically check the captive water pump for wear or signs of leakage from the shaft seal Loosen the drive belt and move the water pump pulley back and forth The pulley should be tight on the shaft and only a slight amount of bearing play should be felt Rebuild the pump if wear is excessive or if the seal leaks Refer to the section on Water Pumps for water pumps service procedures Sea Water Pump Periodically check the sea water pump for signs of leakage from the shaft seal A leaking shaft seal may allow water to enter the crankcase and contaminate the engine oil Remove the pump end cover see Figure 18 and inspect the impeller for cracking or signs of wear The impeller deteriorates with time because of continuous flexing and must be period ically replaced If the impeller fails check for pock marks on its end surfaces This indicates that air has been entering cooling system reducing pump lubri cation and causing overheating Check all hose connections for leaks that could admit air and tighten as required If the impeller fails after short service under 500 hours check for possible defects If impeller blades have broken locate and remove the particles or they will impede water flow When re installing coat the impeller
145. t inserts and thrust washers are available for all main bearings Do not ream the bearings Align the oil holes and press the new bearings into the front and rear housings Insert the center bearing when the crankshaft is re installed Rear Oil Seal The rear oil seal is in the rear bearing plate If damaged drive it out from the inside of the plate Using the oil seal installing too Onan No 420 0250 install a new seal with the rubber lip facing outward open side of seal inward See Figure 117 Drive the new seal flush with the rear surface of the bearing plate Leave the seal installer on during bear ing plate installation to protect the oil seal Installation After each installation step check the crankshaft to be sure it is not frozen into place 1 Press front and rear main bearings into place then align bearing and bearing housing oil holes Do notattemptto drive a bearing into a cold block or rear bearing plate 2 Install thrust washers and locking pins 3 Oil bearing surfaces and install crankshaft from rear of crankcase through rear bearing plate hole Mount and secure rear bearing plate Heattiming gear on an electric burner or oven to about 350 F 175 C Install key on crankshaft then drive gear into place Install retaining washer and lock ring Set upper half of center main housing on crank shaft and rotate it into place See Figure 118 Be sure it is installed with the side marked front towar
146. tall injection pump following the steps for Injection Pump installation in the FUEL SYSTEM section This step is critical CRANKSHAFT The DJ Series engines use a counter balanced duc tile iron crankshaft To increase shaft fatigue durabil ity all crankpin fillets are shot peened during manu facture The two cylinder crankshafts ride on two lead bronze bearings the front one is housed in the crankcase and the rear one is in the bearing plate The four cylinder model uses an additional main bearing with a split center CRANKSHAFT GEAR PULLER GEAR PULLER ONAN NO RING 420 0275 ONAN NO 420 0072 FIGURE 115 REMOVING CRANKSHAFT GEAR Removal 1 Remove lock ring and retaining washer in front of crankshaft gear 2 Pull off crankshaft gear has two 1 4 20 UNC tapped holes for attaching a gear pulling ring Use care not to damage teeth if the gear is to be reused See Figure 115 Remove oil pan pistons and connecting rods Remove bearing cap from center main bearing Remove rear bearing plate from crankcase Remove crankshaft through rear opening in crankcase Catch upper half of center main bear ing support as it slides off its mounting surface an A o Inspection Clean the crankshaft and blow out all oil passages Check journals for out of round taper grooving or ridges Pay particular attention to ridges or grooves on either side of the oil hole areas Unus ual conditions here often
147. ter Pumps for water pump service procedures The minimum water flow requirements in GPM for sea water systems are given in Table 2 If necessary a test can be made to determine if the water flow is adequate Run the engine and use a pail to catch the water that is discharged at the outlet connection on the exhaust elbow during a 15 second period Mea sure the number of gallons collected and multiply that amount times 4 to obtain the flow rate in gallons per minute Compare with the amount shown in Table 2 to determine if the flow rate is sufficient Do not run the generator set for more than one minute if the cooling system is faulty Doing so can result in damage to water cooled exhaust system components as well as to the engine 3 0MDJA 6 0MDJB 7 5MDJE 12 0MDJC 15 0MDJF TABLE 2 COOLING REQUIREMENTS MINIMUM ENGINE WATER FLOW GPM Heat Exchanger or Keel Cooler Sea Water 3 000 6 000 7 500 12 000 15 000 HEAT EXCHANGER COOLING AVAILABLE FROM ONAN COOLING SYSTEM CAPACITY PT WITH HEAT EXCHANGER Test at full load CONNECTED TO EXHAUST MANIFOLD SEA WATER INPUT EXHAUST ELBOW APPLY PIPE SEALANT ASSEMBLY TO ALL PIPE THREADS ff TWO H HOSE CLAMPS HIGH EXHAUST TEMPERATURE RUBBER SHUTDOWN SWITCH EXHAUST HOSE EXS 1014 FIGURE 13 EXHAUST ELBOW Captive Water A second pump metal impeller type is required for the captive water system on engines that have heat e
148. tering principles as the American Bosch PLB pump described earlier in this section Fuel control from idie to maximum speed and power is accomplished by rotating the helix on each pump plunger Both pump plungers and barrel assemblies are rotated 0 to 180 degrees by a fuei control arm yoke and a rack gear Rotating the reciprocating plunger changes the effective length of the plunger strokes and hence the amount of fuel it delivers to the injection nozzle The fuel transfer pump and the primary and secon dary fuel filters in this system are identical to those described for and used on the other DJ series engines Nozzles The MDJE fuel injection system uses either a Diesel Kiki or C A C throttling pintle type nozzle The noz zle ho ders are either Yanmar of Diesel Kiki and have a plated nozzle retaining nut that distinguishes them from Bosch nozzle holders which have a black oxide finish The nozzle tips are interchangeable in Kiki and Yanmar holders but internal components of these holders are not interchangeable The opening pres sure for new nozzles should be 2100 to 2200 psi 14480 15169 kPa High Pressure Injection Lines Both high pressure fuel lines between the injection pump and thetwo nozzles are designed to be installed without any bending Lines that fit on Bryce pump installtions also fit on Kiki pump installations and vice versa Whenever the lines must be removed dis connect both ends Do not bend the lines
149. the high pressure line The spray pattern Figure 33 can be observed as the engine is cranked WARNING Fuel peneiration of the skin might cause severe personal injury Do not let the nozzle high pressure fuel spray against skin surfaces POOR SPRAYPATTERN _ SPRAY PATTERN FIGURE 33 NOZZLE SPRAY PATTERN If streamers are visible the pattern is badly distorted or if the nozzle drips before it reaches opening pres sure it is defective and must be cleaned or replaced Cleaning is the most important part of nozzle maintenance Make sure the work area and equipment are exceptionally clean A second method for identifying a misfiring nozzle is to remove the exhaust manifold run the engine and observe the exhaust ports for the following con ditions Heavy Load Black smokey exhaust from any one cylinder could indicate poor nozzle condition Light or No Load Blue white smoke from any one cylinder could indicate poor nozzle condition Adjustment To adjust the opening pressure remove each nozzle from the engine Remove the plug from the center of the cap nut and loosen the cap nut Install the nozzle to be tested on a static fuel nozzle testing fixture may be purchased from Onan Fol lowing the instructions on the tester adjust the open ing pressure to 1750 psi 12 075 kPa by turning the adjusting screw Clockwise adjustment increases the pressure counterclockwise decreases it Do not try to adjust the pressu
150. they are removed Before installing new or used parts flush them thoroughly with clean fuel and install while still wet BRYCE KIKI FUEL INJECTION PUMPS The Bryce Kiki Injection Pumps are similar in design appearance and performance Figure 59 Both units mount two plunger and barrel assemblies in a single housing and use a common rack gear to rotate the control sleeves and regulate the fuel output of both pumps Although the pumps are interchangeable on the MDJE engines internal components of the Bryce and Kiki Pumps are not interchangeable One exter nal difference is that the Bryce Pump uses an align ment dowel pin to fit it on the adapter assembly The delivery valves on both pumps are also similar but the Bryce has one copper sealing gasket while the Kiki uses a combintion sandwich type seal that requires a special delivery valve pulling tool to remove it Both pumps use roller type tappets as cam followers which are held in place by pins and lock wire Each pump has an air bleed fitting to vent air and permit easy priming CONTROL RACK YOKE KNOB SHIM FIGURE 59 INJECTION PUMP Repair Most fuel system troubles are not due to a faulty injection pump test the rest of the fuel system before condemning the injection pump Onan discourages field repair of the injection pump because of the exceptionally close tolerances be tween parts and because of the need for the special ized equipment necessary for r
151. to shift the pinion into full mesh and measure the clearance between pinion and pinion stop Figure 90 This should be between 0 07 inch and 0 12 inch 3 05 mm as near to 0 070 inch 1 78 mm as possible Adjust the link screw on the end of the solenoid plunger for proper clearance STARTING MOTOR NEED NOT BE REMOVED FROM FEELER GAUGE ENGINE TO MAKE THIS MEASUREMENT SEE TEXT FIGURE 90 PINION CLEARANCE MITSUBISHI STARTER REMOVAL AND INSTALLATION 1 Remove both battery cables from battery Dis connect ground cable first 2 Disconnectbattery cable and electrical lead wires from starter 3 Remove capscrews and flat washers that attach starter to mounting bracket 4 Remove starter 5 Mountstarter motorto engine by a direct reversal of the removal procedure Connect battery cable and wires to starter 6 Connect battery cables to battery Connect ground last MITSUBISHI STARTER DISASSEMBLY 1 Remove M terminal nut and wire lead from solenoid 2 Remove the two solenoid mounting screws and remove solenoid 3 Remove the two through bolts and brush holder retaining screws Remove rear bracket Figure 91 0 07 0 12 CLEARANCE REAR BRACKET THROUGH BOLTS 5 1186 FIGURE 91 REMOVING REAR BRACKET 4 Remove frame assembly and brush holder as sembly while pulling the brushes upward Then remove armature assembly 5 Remove cover assembly snap ring and washer from the pinion sha
152. ttern checked INJECTION NOZZLE TESTER FIGURE 34 Neveruse hard orsharp tools emery paper grinding powder or abras ives of any kind on nozzles or they may be damaged Soak each nozzle in fuel to loosen dirt Then clean inside with a small strip of wood soaked in oil Clean spray hole with a wood splinter If necessary clean the outer surfaces of the nozzie body with a brass brush but do not attempt to scrape carbon from the nozzle surfaces This can severely damage the spray hole Use a soft oil soaked rag or mutton tallow and felt to clean the nozzle valve 5 Clean nozzle valve and polish with tallow and a wooden polishing fixture Take care to remove all traces of tallow when finished 1 Use a brass type scraper tool to remove hard carbon depositis from nozzle body valve seat 6 Examine nozzle valve and body with a magnitying glass If erosion and scoring conditions are found replace the valve and body 2 Afterscraping the carbon polish the valve seat by using a round pointed stick dipped in tallow Pol ishing should restore seat to its original finish unless it is scored 7 Use a lapping plate and compound for flat lap ping of nozzle parts which depend on a lapped surface for sealing A figure 8 motion is used 3 Use a special hooked type scraper to clean the nozzle pressure chamber gallery The hooked end of scraper is inserted into the gallery and then carefully rotated CENTERIN
153. tthis point itis a matter of mechanically adding outside accessory items to the block assembly Order of assembly is reverse of disassembly 7 When engine is complete install controls Check the tagged wires Use wiring diagram to connect leads to control and leads from control to engine All wires are marked for correct identification If the unit is to work properly wires must be con nected correctly 8 The engine is now ready for starting Before final adjustments run the engine about 15 minutes under light load to reach normal operating temperature ASSEMBLY SUGGESTIONS Things to Keep in Mind During Engine Assembly 1 See Onan Tool Catalog 900 0019 many items require a special tool for correct installation Some of these tools are Oil seal driver and guide bearing driver Valve spring compressor valve lock replacer valve guide driver and valve seat remover Gear puller and gear puller rings Piston ring spreader and compressor Flywheel puller pry bar armature puller Torque wrench plastigauge for correct bear ing clearance Armature growler gas pressure gauge manometer 2 Wet holes in crankcase holes through crank case always use copper gasket washers 3 Nuts bolts and screws that do not require exact torque should betightened snugly then 1 4 extra turn 4 Select proper length of any screw or bolt and position in hole Make sure they do not bottom 5 Gasket kits sometim
154. use unconsciousness and death It is an odorless and colorless gas formed during combustion of hydrocarbon fuels Symptoms of carbon monoxide poisoning are e Dizziness e Vomiting e Headache e Muscular Twitching Weakness and Sleepiness Throbbing in Temples If you experience any of these symptoms get out into fresh air immediately shut down the unit and do not use until it has been inspected The best protection against carbon monoxide inhalation is proper installation and regular frequent inspections of the com plete exhaust system If you notice a change in the sound or ap pearance of exhaust system shut the unit down immediately andhave itinspected and repaired at once by a competent me chanic Cooling System Coolants under pressure have a higher boiling point than water DO NOT open a radiator pressure cap when cool anttemperature is above 212 degrees F 100 degrees C or while engine is running Keep The Unit And Surrounding Area Clean e Make sure that oily rags are not left on or near the engine e Remove all unnecessary grease and oil from the unit Ac cumulated grease and oil can cause overheating and subsequent engine damage and present a potential fire hazard E 4 Table of Contents TITLE PAGE General Information 00 ccc ccc cece ete n cece cece eectecescenee 2 Specifications o r icc ave rre eise xeseios ag ed es 3 Dimensions and Clearances
155. ust outlets to prevent entrance of mois ture bugs dirt etc Clean and wipe entire unit Coat parts susceptible to rust with a light coat of grease or oil Disconnect battery and follow standard battery storage procedure 13 Returning a Unit to Service 1 2 oO Remove cover and all protective wrapping Re move plug from exhaust outlet Check warning tag on oil base and verify that oil viscosity is still correct for existing ambient tem perature Clean and check battery Measure specific grav ity 1 260 at77 F 25 C and verify level is at split ring If specific gravity is low charge until correct value is obtained If level is low add distilled water and charge until specific gravity is correct DO NOT OVERCHARGE Ignition of explosive battery gases might cause severe per sonal injury Do notsmoke while servicing batter les Check that fuel injectors and fuel lines are secure and correctly torqued Clean heat exchanger Connect batteries Verify that no loads are connected to engine WARNIN G J Inhalation of exhaust gases might result in serious personal injury or death Be sure deadly exhaust gas is piped outside and away from windows doors or other inlets to building Start engine After engine has started excessive amount of blue smoke will be exhausted until the rust inhibitor or oil has burned away Accidenial starting of the engine might cause sever
156. ved prior to injection pump timing Since injection occurs at the port closing position the PC mark can be located only by comparing the old fiywheel with the new one or by measuring the piston drop from its top center position on the compression stroke of number one cylinder Piston drop data is given in Table 7 TABLE 7 PISTON DROP DATA PORT PISTON DROP CLOSING mms mm 019 0 128 3 25 MDJB amp MDJC 19 degrees Begin Spec P 0 155 3 94 MDJB amp MDJC 21 degrees Prior to Spec P 0 128 MDJE Spec A AA 19 degrees 0 115 29 Begin Spec 18 degrees 0128 325 MDJF 19 degrees Replace any injection pump that troubleshooting procedures prove to be malfunctioning Do not attempt unauthorized repair procedures on the injection pumps Fuel injection pumps must pass stringent quality inspections and tests with precise settings and adjustments in order to meet Onan s performance and reliability requirements Therefore it must be clearly understood by the owners and by Onan ser vice personnel that tampering or inept repair attempts can cause irrepairable damage to the pumps that will not be covered by the manufacturers warranties or exchange agreements Contact an authorized Amer ican Bosch Service station or Distributor for expert repair service on injection pumps The Repair service should include cleaning part replacement static pressure tests for internal and external
157. w is BELOW the load water line The siphon break see Figure 14 is a vacuum operated vent valve that opens the exhaust water discharge line to the atmosphere when the engine shuts down The open valve prevents flotation water from being siphoned into the exhaust manifold The siphon break is mounted no less than 12 inches 305 mm above the water line If space is limited it may be remotely mounted but must be within 5 feet more than 1 5 m of the exhaust water injection elbow In all installations the siphon break must be mounted vertically with the threaded end pointing down Be sure the slotted opening in the vacuum relief valve is open to at mospheric pressure The siphon break will not func tion if the relief valve slot is closed in any way HANGER STRAPS VACUUM RELIEF VALVE ADAPTER ELBOW 2 RUBBER HOSE WATER OUTLET EXHAUST WATER INJECTION ELBOW I EXHAUST OUTLET FIGURE 14 SIPHON BREAK HEAT EXCHANGERS Several types of heat exchangers are currently in use with marine cooling systems The front mount type of heat exchanger shown in Figure 15 is used with the MDJA and MDJB and was used with earlier models of the MDJE and MDJF It is mounted atthe front ofthe engine perpendicular to the engine center line The end caps are removable for cleaning and a separate expansion tank is required The sea water side of these heat exchangers is protected from corrosion with either one or two zinc pencils mounted on p
158. with grease and make certain the impeller cover is air tight Tighten the cover screws to 15 17 inch pounds 1 70 1 92 Nm Refer to the section on Water Pumps for water pump service procedures 24 FIGURE 18 END COVER REMOVAL WATER PUMP REPAIR This section covers removal repair and installation procedures for all metal impeller and neoprene impeller water pumps used with Onan marine liquid cooled engines Repair Kits are available for most water pumps Table 3 shows the water pumps used with Onan marine liquid cooled engines Metal impeller pumps are required for circulating HOT engine coolant They are most commonly used with marine cooling systems that use a heat exchanger Neoprene impeller pumps may be used only for pumping COOL water because the impeller deterio rates rapidly in hot water They are most commonly used for pumping sea water in marine cooling systems TABLE 3 WATER PUMPS METAL IMPELLER PUMPS 132 0110 132 0074 With Heat Exchanger With Keel Cooler MDJA Also for Keel Cooler Models MDJB MDJC MDJE MDJF NEOPRENE IMPELLER PUMPS 131 0257 131 0152 182015 132 0147 1320059 MDJA Begin Spec E MDJC Spec S MDJF Begin MDJA Spec MDJB Begin Spec L w heat exchanger 1976 with heat A D Begin Spec D before 1976 exchanger MDJB Spec w o heat exchanger w heat exchanger A K Spec D R with MDJC Spec heat exchanger A C
159. xchangers or keel coolers This pump circulates engine coolant continuously through the water jacket tothe heat exchanger or keel cooler Check all hoses for kinks or bends that could restrict the water flow and correct as required WATER COOLED EXHAUST Marine exhaust systems are designed so that a minimum amount of heat will be radiated from the exhaust system components This is doneto keep the heat build up in the engine compartment to a mini mum Exhaust heat is dissipated by using a water cooled exhaust manifold and a water injected exhaust pipe and muffler system The exhaust manifold is encased in a shell through which engine coolant or sea water is circulated Just beyond the exhaust manifold a special elbow see Figure 13 is fitted which allows the output water from the sea water system to be injected into the exhaust pipe The injected sea water is carried out through the exhaust system and discharged Typical Installations All water injected exhaust systems must be designed sothatthe discharge water will notflow back into the engine There are several methods that can be used to keep water out of the engine All are based on injecting the water at a point a few inches approxi mately 4 102 mm belowthe exhaust manifold outlet and installing a sharp drop in the exhaust line that water cannot normally fiow over SIPHON BREAK A siphon break is used with all marine installations where the exhaust water injection elbo
160. y of less than 3 hertz 2 hertz is usually attainable INJECTION PUMP GOVERNOR SPRING STUD Govemor arm must b of hole in governor shaft 493 be flush with bottom OVERNOR OVERNOR STUD SENSITIVITY ADJUSTING RATCHET DECREASE SPEED DECREASE 1 SENSTTIVITY p SPEED INCREASE SENSITIVITY FIGURE 74 MDJA BEGIN SPEC R GOVERNOR ADJUSTMENTS GOVERNOR ARM GOVERNOR FLYBALLS GOVERNOR YOKE TURN TO INCREASE R P M HOLD SPRING STUD IN POSITION TURN FOR MINIMUM SPEED DROP THEN ADJUST NUT ENGINE SPEED SPRING NUT ADJUSTMENT STUD AND NUT FIGURE 73 MDJA GOVERNOR ASSEMBLY PRIOR TO SPEC R Oil System Onan diesel engines have pressure lubrication to all bearing surfaces of the engine The oil system in cludes an oil intake cup a gear type oil pump a by pass valve a full flow oil filter and passages and drillings through the block for oil delivery Figure 75 shows the pressure oil system A thin film of oil from the crankcase lubricates the cylinder walls and the rings wipe the excess oil off to prevent passage of oil to the combustion chamber The upper portion of the cylinders are partially lubri cated by the fuel The connecting rod bearings are critically in need of lubrication because of the high pressures and high rotating speeds Bearing lubrica tion and cooling are very important to the life of an engine Normal oi pressure sh

974-0750 Onan MDJA to MDJF Marine Diesel Engine Service Manual

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