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Содержание MJA Series

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Страница 3: ...anual primarily for reference when servicing MJA MJB and MJe generat ing plants Tbis is what it was designed for But inaddi tion ONAN recommends that you study the whole manual It will help to acquain...

Страница 4: ...6 Specification Number Denotes Customer Requested Deviations from Standard Model 1 Specifica tif fl Letter Advances with ONANchanges 5M JB Some models have generators reconnectib1e for either code 1 2...

Страница 5: ...Cylinder Heads and Valves 3 8 Pistons Connecting Rods Cylinders 3 9 Engine Disassembly 4 GENERATOR REVOLVING FIELD 705MJB MJC 5 GENERATOR REVOLVING FIELD 3MJA 4MJA and 5MJB 6 CONTROL SYSTEM 7 ASSEMBL...

Страница 6: ...3 7 3 3 4 3 3 3 6 2 3 2 6 3 3 4 5 3 2 7 3 9 3 3 4 3 9 3 SUBJECT Flyball Spacer see camshaft gear Fly vheel Fuel Fuel Pump Fuel Strainer Gasoline Carburetor Gear Cover Generator Blower Generator Brush...

Страница 7: ...enerator Air Baffle Battery Charging Winding Brushes Bearing EXCiter Rotor Collector Rings SECTION 3 8 5 3 5 6 3 5 1 3 5 4 3 5 5 3 5 2 3 5 3 9 5 5 3 9 2 2 3 9 2 3 7 5 3 5 2 3 8 3 3 8 4 3 B 6 3 B 5 7 2...

Страница 8: ...II1I IaI is I I E III II IaI II III IaI IaI 0 l 1 l 5 z i m TI e II u r 0 0 l m il z 1 e U I TI TI 00 r II l 0 r or 1 r em e II m e e l en u r il l en m lz _I r u r I 0 zm mm 1 ilm u r m e r l 1 J IO...

Страница 9: ...I I __ J 1 t g t J r I i t Ii W II I j 7 u r l__ I t 1 ale 1 111 I tl p I J iF tU I 0 J e 6 u l I l c I I I E __ 1 I I i icJ I N l _ JI I f I I l M t j J t I I SPARI PLUGS START DISCONNECT SWITCH AND...

Страница 10: ...0 il 0 re rn 0 rnfJ r 0 i i m 0 r Q r OJ l fJ 0 rn 0 tJ tJ Q 1ft 1ft nI nI Ill 1ft Q z i I I I AI 61ft 1ft 6 0 i fJ l i i fJ i i I Ir AI 0 0 e fJ r e i rn Zrn 11 r r e m i 11 6J1e 7 l 1 r cO e fJ i f...

Страница 11: ...Check Fuel Supply x 3 2 1 Check Oil Level x 3 5 1 Clean Governor Linkilge I it 3 4 1 Service Air Cleaner Silencer xt 3 2 6 Change Crankcase Oil x 3 5 1 Clean Crankcase Breather x 3 5 7 C ean and Adiu...

Страница 12: ...2 v 12 v 12 v two in sertes two in two in two in series 105 series series 165 105 105 5 MJBGONTROLWffirnG DlAGRAM low oHpressure ctrcmt E It i 3 I r 1 z sX r I I __ 1 Il Priorto SpecF Models e z r t 9...

Страница 13: ...discharged See Trouble Shooting Chart 7 Control circuit defective See Sect 6 Internal seizure Disassemble engine and repair Engine oil too heavy for See Sect 3 5 1 for oil operation in low temper reco...

Страница 14: ...e 1 1 1 LDZ Ul o ttl IO C j t Z 0 _ Defective fuel pump Ignition system faulty See Trouble Shooting Chart 4 Carburetor choked too Check choke adjust much ment Sect 3 2 4 Air intake restricted Clean a...

Страница 15: ...oints Engine races stop Too much fuel caused by I engine immediately Disconnected governor by pushing throttle mechanism lever Engine stops Emergency shutdown unexpectedly circuit operated I Internal...

Страница 16: ...j P Ii1 iz mop I ln rrf l l _ n OAKE u l U J _ 6 IL S 1 l I l s U t i W ii p r t l Engine misses at light load See Sect 3 2 4 Improper choke operation Clean cylinders See Heavy carbon deposits in Sect...

Страница 17: ...tight i Defective ignition sys tem Adjust lash Sect 3 7 1 See Trouble Shooting Chart 4 Engine backfires Excess oil con sumption light blue smoky exhaust Lean fuel mixture Clogged fuel screen Adjust c...

Страница 18: ...nder load Fuel mixture too rich Choke not open i Clogged air intake I RE MEDY Inspect engine check for clogged crankcase breather Inspect oil seals Sect 3 9 2 2 and Sect 3 9 5 5 Check for clogged cran...

Страница 19: ...lace bearings knock bearing Low oil supply Add oil check for cause of low oil Sect 3 5 Oil badly diluted Replace oil Pinging sound Carbon in cylinder Remove carbon when engine is suddenly or Spark too...

Страница 20: ...ct the generator wiring diagram a ing to the model phase and number of output wires Select the citer wiring diagram from the Magneciter model number on the p nameplate For revolving armature plants se...

Страница 21: ...ing System HI The cooling system on the MJA MJB and MJC generating plants is a liquid coolant pressure circulating open type system that uses raw coolant city water sea water NOTE Factory installed he...

Страница 22: ...air leaks 1 To measure water flow install a tank of kl 1 wn quantity at the water outlet Run the engine until the thermostat opens and thEm measure the length of time necessary to fill the tank From t...

Страница 23: ...g system run the engine insert the cooling system outlet into a tank of water and watch for bubbles If bubbles appear inspect the cooling system thoroughly to find the source 3 1 3 REPAIR Whenever mak...

Страница 24: ...vailable either factory installedoI as a kit for customer installation A completed heat exchanger install 3 tiQIJ contains 2 water systems the closed water system and raw water sys V 1 1 1 rIo V J J L...

Страница 25: ...ds after the centrifugal switch has closed If ile plant automatically shuts down determine and correct the ause and then restart by pushing thE reset button on the emer ency relay The re set button wi...

Страница 26: ...Shing is completed check the system thoroughly for leaks uncovered by the cleaning operations CONTROL SYSTEM For disassembly and repair of the timing gear and switchop erating mechanism see Sect 3 3 6...

Страница 27: ...ch contact gap at 020 in Fig should become clogged remove the ends and clean out the tubes 3 1 4 5 Centrifugal Pump Repair The centrifugal fresh water pump is mounted on the heat exchanger bracket If...

Страница 28: ...r replace The gap with the plant stopped should be maintained at 020 in Clean and flush cool For a complete description and repair instructions see Sect ing system and6 3 1 4 Replace thermostat 6 3 TE...

Страница 29: ...lier ldels See Sect 6 3 3 4 1 pressure occurs the pressure switch closes completing the H circuit Thls operates the relay disconnecting engine ignition which stops the plant The centrifugal switch is...

Страница 30: ...s are all current replacement parts The epoxy filled solen are identified by two part numbers stamped on the bottom thE style solenoids h ve only one number stamped on the housing Improper use If the...

Страница 31: ...Y STYLE FIG 6 B OVERTIGHTENED START SOLENOID CONNECTIONS FUEL SYSTEM If fuel is stored for any great length of time it can oxidize and form gums the fuel becomes stale ONAN recommends changing fuel st...

Страница 32: ...he cover and lift out the valve and cage assemblies 5 Drive out the rocker arm hinge pin 6 CONTROL SYSTEM The plant control system controis starting stopping battery n ing and provides a means of emer...

Страница 33: ...Fuel pump failure is usually due to a leaking dia phragm valve or valve gasket A kit is available for replacement of these parts Because the extent of wear cannot be detected by the eye replace all p...

Страница 34: ...ening the choke plate 3 2 4 l Adjustment Electric Choke Under normal operation adjust the choke so the distance measured between the choke plate and carbu retor throat Fig 3 2 E is as shown in the tab...

Страница 35: ...ay be necessary to readjust the choke for best operation For more chOking turn the cover clock wise for less choking turn it counterclockwise 3 2 4 2 Disassembly and Repair Electric Choke If the choke...

Страница 36: ...sition NOTE If a voltmeter isn t available use the above procedu mark the point where arcing begins Fuel enters the carburetor through the inlet valve Fig 3 2 G and pas ses into the float chamber To c...

Страница 37: ...n FUEL SYSTEM adjusting needle As the throttle is opened to increase power it grad ually exposes the idle transfer port and fuel is drawn out through this port also As the engine governor opens the th...

Страница 38: ...stop pin with the plant operating at no load This pre ents excessive hunting when a large load is suddenly remo ed 3 2 5 2 Remo al and Disassembly 1 Remm e the fuel line gO ernor linkage and electric...

Страница 39: ...ntrol box and float should fit freely on its connections If a defective coil is found disassemble the gen pin without binding Invert ect 5 4 and replace the defective coil the c arburetor body and mea...

Страница 40: ...ency Atthe time engine speed determines generator output voltage so volta be adjusted over asmaU range by adjusting thegovernormechan The voltage drop from no load to full load operation is determine...

Страница 41: ...icker with the average load on the plant Set gap at 025 FIG 6 C ANTI FLICKER BREAKER POINT GAP FUEL SYSTEM 3 2 7 EXHAUST SYSTEM The exhaust system is normally supplied by the user and installed in the...

Страница 42: ...eries indings act as the starting motor field The shunt ings are the working field they produce the magnetic field in w the armature turns to produce useful output NOTE Beginning Spec F 5MJB plants us...

Страница 43: ...bUild up wltage slow to build en to twenty per cent ated voltage uter I roltage builds up nor LIt less than rated after build up loltage builds up nor ith slIghlly less than lItage at no load and age...

Страница 44: ...d checking the ignition breaker point gap i u J1 C ircuil breaker opens i iaGout five seconds checking and cleaning spark plugs t C I OutJlutvoltage slow to build ins pecting both the low and hi tensi...

Страница 45: ...e engine can be timed either stopped or running at rated speed With the engine stopped timing should be set for ignition at 50 ATC with the engine running at rated speed 250 BTC Always adjust the brea...

Страница 46: ...tion breaker points 3 Remov e the 2 capscrews holding the breaker plate assembly and pull off the plate 4 Pull out the cam and weight assembly spacermaunted on the gear shaft Be careful not to lose th...

Страница 47: ...4 0 4 5 stall lead Bl on the adjustable resistor plete assembly must be replaced Clean FIG 3 3 E CENTRIFUGAL and inspect the bearing surfaces in the WEIGHT SPRING DATA UTION Check this lead to see tha...

Страница 48: ...10000 ohms for the secondary winding E tremely low resistance usually indicates a shorted winding and extremely high resistance usually indicates an open in the winding WARNlNG The 4 volt coils MJB M...

Страница 49: ...make coil ahd WindiIlg testers for Which test data is available 3 3 4 MJC IGNITION SYSTEM TheMJC generating plant uses a suppressed battery ignition system with dual breaker points to produce and dist...

Страница 50: ...wever they may be checked for proper timing by plac inga timing mark on the flywheel 1800 from the TC mark Then re peat steps 1 5 substituting cylinder 2 101 cylinder 1 and the new timing mark for TC...

Страница 51: ...eel 3 If the timing pointer on the gear cover indicates 250 BTC timing is correct Otherwise loosen the distributor body clamp and rotate the distributor body to adjust timing If timing is early 250 ma...

Страница 52: ...J Replace the rotor if it is grounded or has an open circuit or short 4 3 2 2 stator Continuity Tests Disconnect the generator output leads in the control box Use the wiring diagrams in Sect 10 to de...

Страница 53: ...ng solvent When dry in spect all components Inspect the centrifugal advance component for signs of wear and replace any that appear WOrn or otherwise damaged Inspect the cam and shaft for wear or scor...

Страница 54: ...d mesh the distributor and cam shaft gears 3 Install tbe distributor clamp screw right side of the plate and swing the assembty outward Tore move the brush holders unscrew the 4 machine screws on the...

Страница 55: ...il maintenance should include inspecting and tightening the terminals and cleaning them if necessary A quick check for possible coil failure can be made by simply discon necting the high tension spark...

Страница 56: ...conll winding less current in the gate winding and generator field and output voltage Next we must introduce a regulator so that the current in the cor windings will depend on the voltage output of t...

Страница 57: ...ent actor allows to flow in the gate winding is dependent on the amount gnetism in the core The current flow increases the gate open there is more magnetism in the core until finally when the core ura...

Страница 58: ...d to the engine crankcase througb the en to generator adapter The rotor is directly connected a taper with key to the engine crankshaft A ball bearing housed in the genera tor endbeU supports the outb...

Страница 59: ...ain bearing support requires ement the whole crankcase must be replaced or returned to the Y to have a new housing fitted CENTER MAIN BEARING CAP ARING HALF BOLT SIDE MARKED FRONT I TOWARD CRANKSHAFT...

Страница 60: ...3 1 5 volying 63 59 60 45 90 1770 1830 1770 18S0 3 48 51 49 52 1 I IArm 50 ature 1440 1530 1470 1560 90 3 2 E e _ 6 59 3 64 57 60 60 valying 90 1920 17 Z 9r fl8 3 Q 1770 4f i1 4 3 1 54 Field 50 1410 j...

Страница 61: ...air Check all journals for out of round grooving or ridges Pay particular attention to ridges or grooves her side of the oil hole areas Unusual conditions here often point vious neglect of oil cleanli...

Страница 62: ...specified the bearings show cracks breaks burrs excessive wear or a defects The camshaft to bearing clearance should be 0012 to 0037 check the rear bearing remove the expansion plug at the rear 0 cran...

Страница 63: ...HOLES FRaN BEARING i FIG 3 9 E CAMSHAFT BEARING INSTALLATION OIL SYSTEM 3 5 1 MAINTENANCE Periodic oil system maintenance should include changing crankcase oil cleaning the crankcase breather Sect 3 5...

Страница 64: ...oryoke so the smooth side is toward governor 3 Turn the governor cup so the stop pin in the gearc over will one of the holes in the cup surface Fig 3 9 B Measure th tance from the end of the stop pin...

Страница 65: ...s in place Fig 9 B i I 11j INSTALL OIL SEAL FLUSH WITH THIS SURFACE THIS SURFACE MUST BE CLEAN BEFORE INSTALLING SEAL FIG 3 9 C GEAR COVER OIL SEAL OIL SYSTEM 3 5 6 OIL FILTER The full flow filter is...

Страница 66: ...To install a new ring gear place TO it in an oven heated to 380 4000 LOOSEN FLYWHEEL F for 30 to 40 minutes CAUTION DON T HEAT WITH A TORCH When heated properly the ring will fall into place on the fl...

Страница 67: ...es cylinder condition Worn cylinder walls Refinish cylinders and pistons replace pistons Leaky head gasket Replace head gasket ton and cylin Operated with dirty air Change air cleaner and ring wear cl...

Страница 68: ...rmature 3 6 2 TESTING Poor cranking performance can be caused bya faulty starting motor defective battery insufficient capacity battery or high resistance in the starting circuit STARTING MOTOR l r ri...

Страница 69: ...n 1 290 and 1 225 If not recharge the bat tery If the battery won t recharge replace it With the starting motor operating check the voltage drops 1 from the battery ground terminal post not the cable...

Страница 70: ...Pistons and rings are available in 010 020 and 030 size If the cylinders don t need refinishing remove any exi ting riOg the top of the wall with a fine stone 3 8 3 PISTONS Thoroughly clean and inspe...

Страница 71: ...y 3 6 4 REPAIR STARTING MOTOR 3 6 4 1 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 ea...

Страница 72: ...are absorb ent bearings designed to hold up to 25 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 e...

Страница 73: ...and 12 as aear 07 as possible Adjust the link screw on the end of the solenoid plunger for proper clearance NOTE On plants built before March 1962 it was necessary to main tain the gap between ring ge...

Страница 74: ...encil marks at intervals b valve face and observe if the marks rub off uniformly when valve is rotated part of a turn in the seat If the seat isn t t regrind the valves 4 Using a valve spring compress...

Страница 75: ...nder head assembly contains valves valve seat inserts and guides rocker arms and spark plugs The valve assem blies are operated by pushrods running through the cylinder block to the camshaft Exhaust v...

Страница 76: ...s assem le the valve ass bhes f 4 F t r i L 3 7 4 REPAm Thoroughly e1ean aU comp Ohentg 61 tl1e cylinder head assemblies Remove ail the carbon depOSits from the combustion chambers an clean all gasket...

Страница 77: ...1 Be cylinder head assemblies Remove all the carbon deposits from the combustion chambers and Clean all gasket surfaces 3 7 4 1 Valves Remove all carbon and check each valve for burn ing pitting or w...

Страница 78: ...d no valve seals 3 7 Cylinder Heads and Valves Each cast iron cylinder head assembly contains valves valve seat inserts and guides rocker arms and spark plugs The valve assen bUes are operated by push...

Страница 79: ...the valve is rotated part of a turn in the seat If the seat isn t tight regrind the valves 4 Using a valve spring compressor compress each valve spring with its spring retainer in place and insert th...

Страница 80: ...nion stop Fig 3 6 D This should be between 07 and 12 a 07 as possible Adjust the link screw on the end of the solenoi plunger for proper clearance NOTE On plants built before March 1962 it was necessa...

Страница 81: ...designed to hold up to 25 of their own weight in oil Be Ere the felt oil pad is in the outer end of the commutator end bearing hen the motor is assembled check the armature end play It should betv ee...

Страница 82: ...e reinstalle position the starter correctly 3 6 4 REPAIR STARTING MOTOR 3 6 4 1 Armature Inspect the armature for mechanical defect before checking for grounds or shorted coils To test for grounds use...

Страница 83: ...er size If the cylinders don t need refinishing remove any existing ridges frQn the top of the wall with a fine stone 3 8 3 PISTONS Thoroughly clean and inspect e ach piston Clean the carbon from the...

Страница 84: ...nder using a ring compressor tool Each assembly should be installed Check the charge condition of the battery with a hydrometer SPI gravity should be between 1 290 and 1 225 If not recharge the tery I...

Страница 85: ...e start disconnect relay is rod Fig 3 8 D ergized Theover running clutch protects the starter armature from 1 i erspeeds 6 1 MAINTENANCE riodicallychecktbe starting circuit wiring for loose or dirty c...

Страница 86: ...ket Refinish cylinders replace pistons Replace head gasket Clogged oil passages Clean all lines oil passages Piston and cylin der and ring wear Operated with dirty air cleaner Change air cleaner servi...

Страница 87: ...e screws holding the gear COVer to the crankcase To loosen the gear cover tap itwith a soft hammer capscrews to pull the flywheel 3 9 1 1 Ring Gear To remove the ring gear if damaged s w part way thro...

Страница 88: ...or binding and see that thegovernor shaft end thrust ball is in place Fig 3 9 B I I 1 tJ INSTALL OIL SEAL FLUSH WITH THIS SURFACE THIS SUR ACE MUST BE CLEAN BE ORE INSTALLI NG SEAL FIG 3 9 C GEAR COVE...

Страница 89: ...r will fit into one of the holes in the cup surface Fig3 9 B Measure the dis tance from the end of the stop pin to the mounting face of the cover n should be 25 32 in If it isn t replace the 4 Use the...

Страница 90: ...lA 1 I t CEN ER BEARING PRESS BEAR1N F LUSHWITH FRONT CRANK CASE SURFACE LlGNOIL HOLES FRON I 8EARIN I i 1 G i I 1 FIG 3 9 E CAMSHAFT BEARING INSTALLATION OIL SYSTEM 3 5 1 MAINTENANCE Periodic oil sys...

Страница 91: ...breaks burrs excessive wear or other defects The camshaft to bearing clearance sbould be 0012 to 0037 To check the rear bearing remove the expansion plug at tbe rear of the crankcase Press new bearin...

Страница 92: ...oughly clean the crankshaft and blowout all oil passages with compressed air Check all journals for out of round taper grooving or ridges Pay particular attention to ridges or grooves TROUBLE Speed to...

Страница 93: ...3 Q 1770 3 90 2 60 50 54 1620 41 1410 5r 4 1c O l47D 3 90 1 30 I I c cc i i Numbers in pa reri s _ar PJ ant speed in rpm FIG a 4 B FRl QUEN AND SPEED TABLE I1 NtilNE IHSASSE MBLY 91 REAR BEARING PLAT...

Страница 94: ...to the factory to have a new housing fitted BOLT CENTER MAIN IJ lr S DE MARKED FRONT BEARING CAP I TOWARD CRANKSHAFT I j GEAR BEARING HALF J O J i PLACE UPPER BEARING HOUSING HALF IN POS CRANKSHAFT l...

Страница 95: ...ugh the engine to generator adapter The rotor is directly connected a tapered fit with key to the engine crankshaft A ball bearing housed in the genera tor endbell supports the outboard collector ring...

Страница 96: ...nd a control winding The amount of current the reactor allows to flow in the gate winding is dependent on the amount of magnetism in the core The current flow increases the gate open when there is mor...

Страница 97: ...field and a lower output voltage Next we must introduce a regulator so that the current in the control windings will depend on the voltage output of the generator The reg ulator must allow little or n...

Страница 98: ...3 3 4 4 MTClgnition Coils The MTC generator uses two suppre ignition coils mounted on the intake manifold Normal ignition coi maintenance should include inspecting and tightening the terminals cleani...

Страница 99: ...nnect the coil leads to the breaker point cover adapter See ect 3 3 H Ii REVOLVING FIELD G ENERATOR rightsideo f the plate and swing the assembly Qutward Tore move the brush holders unscrew the 4 mach...

Страница 100: ...s except the conde1 breaker points and bushings in light cleaning solvent When dry i spect all components Inspect the centrifugal advance component f signs of wear and replace any that appear worn or...

Страница 101: ...or short 4 3 2 2 Stator Continuity Tests Disconnect the generator output leads in the control box Use the wiring diagrams in Sect 10 to de termine the output lead coding 1 Using either the test lamp o...

Страница 102: ...a multirfJeter IGNITION SYSTEM 2 Run the plant at rated speed Aim the flashing timing light tow the flywheel 3 If the timing pointer on the gear cover indicates 250 BTC timi correct Otherwise loosen t...

Страница 103: ...0 from the TCmark Then re eat steps 1 5 substituting cylinder 2 1m cylinder 1 and the new ming mark for TC Later flywheels have BC Bottom Center mark iming Engine Running IstaHan automotive timing lig...

Страница 104: ...d fails to ate it should then be tested on anyone of the popular make c windi 1g testers for which test data is available 3 3 4 lIIfJC IGNlTION SYSTEM The lIIfJC generating plant uses a suppressed bat...

Страница 105: ...range from 5 2 ohms for the priInary inding and froIn 4000 10000 ohIns for the secondary wind ng emely low resistance usually indicates a shorted winding and Ktremely high resistance usually indicate...

Страница 106: ...nd out without catching in CJ ml IU either end position Inspect the gear ramp for notches or other defects If any part of DIMENSION TENSI A INPOU the cam weight and gear assembly sticks the complete a...

Страница 107: ...crews holding the breaker plate assembly and ull off the plate ull out the cam and Weight assembly Be careful not to lose the Jacermountedon the gear shaft REVO L VIN G FTELD GKN ERA TORf 05 TROUBLE S...

Страница 108: ...g see Sect 3 3 3 2 3 3 3 2 Timing The engine can be timed either stopped or run rated speed With the engine stopped timing should be set for i at 50 ATC with the engine running at rated speed 2So BTC...

Страница 109: ...inglhe ignition timing NATURE OF PROBABLE CORRECTIVE TROUBLE CAUSE ACTION Gener ator will not build up Circuit breaker in off Reset and close breaker voltag or tripped po ition Open in ci rcuit iJreak...

Страница 110: ...rol ReactOl and replace if defective Check wiring diagram for pularity of Com pouud windL s through Reactors A and Band test for continuity Check wiring diagram lor polarity or Corn pound winding 1hro...

Страница 111: ...are the working field they produce the magnetic field in which the armature turns to produce useful output 1 NOTE Beginning Spec F 5MJB plants use a separate automotive start er rather than the serie...

Страница 112: ...resistor is located on the right side of the control box If flicker becomes exceSSive adjust the resistor by moving its slider Adjust it for minimum flicker with the average load on the plant Set gap...

Страница 113: ...sting the governor mechanism The voltage drop from no load to full load operation is determined by the engine governor sensitivity To adjust output voltage slightly within the range shown in Fig 5 D a...

Страница 114: ...ect values If the windings are warm from running the resistance will be slightly higher than specified If the resist ance is high check for an open circuit in one of the parallel wind ings step 3 othe...

Страница 115: ...e plant tin at no load This pre ents excessive hunting when a large load denly removed 2 Removal and Disassembly emo e the fuel line gm ernor linkage and electric choke wire emOve the 2 carburetor mou...

Страница 116: ...tified by a chisel mark on the brush rig Fig 5 1 If Lhe mark is lost or a new brush rig installed follow these instructions to find the neutral position FUEL SYSTEM adjusting needle As the throttle is...

Страница 117: ...ce draws fuel up thr ugh the hollow center lain adjusting needle through passages in the carburetor body ile port Bleed holes in the main adjusting needle allow air to I and mix with the fuel When the...

Страница 118: ...less choking turn it counterclockwise 3 2 4 2 Disassembly and Repair Electric Choke If the choke not operate or won t maintain its adjustment disassemble it for pair If it won t close check for bindi...

Страница 119: ...models of generating plants use an automatic electric Fig 3 2 A An electric element controls the automaztie electric Before the plant starts the choke is closed When the plant rted the generator suppl...

Страница 120: ...ir Fuel pump failure is usually due to a leaking phragm valve ar valve gasket A kit is available far replacemer these parts Because the extent of wear cannot be detected by thE replace all parts in th...

Страница 121: ...ge pin 60 CONTROL SYSTEM The plant control system controls starting stopping battery recharg ing and provides a means of emergency automatic stopping The con trol system and control system defects can...

Страница 122: ...y MJB only Fig 6 A shows a start ing cycle To stop the engine the stop switch grounds the stop relay breaking the ignition coil circuit EARLY STYLE FIG 6 B OVERTIGHTENED START SOLENOID CONNECTIONS FUE...

Страница 123: ...noids h ve only One number stamped on the Improper use If the start switch is released when an engine slows at the peak of the first compression stroke the large current pass through the solenoid may...

Страница 124: ...MJB models See Sect 6 3 3 4 If low oil pressure occurs the pressure switch closes completing the relay coil circuit This operates the relay disconnecting engine ignition system which stops the plant T...

Страница 125: ...d Centrifugal switch The centrif ugal switch is open when the plant is stopped During the starting cycle it closes when the plant speed reaches about 900 rpm The gap with the plant stopped should be m...

Страница 126: ...h leads when the engine starts COOLINGSYS TE M 3 1 4 3 Repair and Testing Raw Water System Test for air I and insufficient water flow as described in Sect 3 1 2 Repair of rubber impeller pump was cove...

Страница 127: ...ect 3 3 6 3 1 4 starting Solenoid 307B40 This solenoid is the same as that described in Sect 6 2 1 1 6 3 2 BATTERY CHARGING CIRCUIT This circuit in cludes the adjustable charge resistor j ectifier and...

Страница 128: ...d to shut down the plant if oil pressure is not sensed by the low oil pressure switch within 15 seconds after the centrifugal switch has closed If the plant automatically shuts down determine and corr...

Страница 129: ...eat exchanger installatlol 2 water systems the closed water system and raw water sys I J L 1 LJ 1t L i J t I J 1 L 10 f ing element on the relay a solder connection holding the spring loaded contacts...

Страница 130: ...Air leaks are an important cause of premature impeller fail To test for air in the cooling system run the engine insert cooling system outlet into a tank of water and watch for bubb If bubbles appear...

Страница 131: ...ecessary tofm the tank From this in the flow in gallons per minute GPM Minimum values are 9 lADLI ur LI AKA I All values in inches unless otherwise specified CAMSHAFT Bearing Journal Diameter Front Be...

Страница 132: ...lts 420 Amps 7 8 lb ft Min 32 40 ounces with new brushes 3405 3415 001 003 450 019 See Fig 3 7 B 015 3405 3415 0025 0045 450 023 See Fig 3 7 B 020 1 25 32 4690 4695 467 468 344 345 342 343 3 1 Cooling...

Страница 133: ...rd ingto the model phase and number of output wires Select the Magne citer wiring diagram from the Magneciter model number on the plant nameplate For revolving armature plants select the generator wir...

Страница 134: ...ly Add oil chec k cause of low oi 3 5 Oil badly diluted Replace oil Pinging sound Carbon in cylinder Remove carbon when engine is suddenly or Spark too early Adjust breaker heavily loaded Retime spark...

Страница 135: ...rings I Loose piston I l TO CONTROL eOl See Sect 3 2 4 t 111 MZ Clean air cleaner Sect 3 2 6 lI MI Replace bearing 4MJA Revolving Armature 3 Wire Sillgle Phase S I M TO Oo M 3 1 0 AI he Add oil REA t...

Страница 136: ...t TROUBLE POSSIBLE CAUSE REMEDY Engine misfires Valve lash too tight Adjust lash Se at heavy load cont Engine backfires I Excess oil con sumption light blue smoky exhaust Defective ignition sys tern S...

Страница 137: ...n See Sect 3 2 4 Heavy carbon deposits in cylinders I Clean cylinders See Sect 3 2 I F aulty carburetion See Trouble Shooting Chart 3 nisses load Spark plug gaps too narrow Set at 025 Intake air leak...

Страница 138: ...Engine stops unexpectedly Clean air cleane Restricted air intake Low engine lPower Check back pres High exhaust back pres Sect 3 2 7 sure Water in gasoline I Change fuel i Inspect all gaskJ manifold...

Страница 139: ...ect operating pro cedures or adjust choke hard to Restricted air intake Clean air cleaner Sect 3 2 6 Poor fuel Change fuel Defective ignition sys tem Incorrect timing Defective fuel pump Poor compress...

Страница 140: ...fuel POSSIBLE CAUSE REMEI Battery discharged See Troubh i She Chart 7 Control circuit defective See Sect 6 Internal seizure f i Engine oil too heavy for I operation in low temper ature Disassemble en...

Страница 141: ...cale 5 0 5 3 water flow gallons per minute 4 4 otiledi xhaust manl fold nO yes nand molded ibration mounts yes yes lm il e comnlend ed powertake off from uHey at any load 2 hp 2 hp take oll limit at r...

Страница 142: ...x Check Fuel Supply x 9il Le e L x x _an Governor Linkaa Service Air Cleaner Silencer xt Chane e Crankcase Oil x Clean Crankcase Breather x Clean and Adjust Spark Plurrs x Check Breaker Points x Check...

Страница 143: ...r is In r i I m m U til til U OJ 0 6 6 o x In In en I l I en i i i i I AI o C I r m I j 1 C 1 o r J 7z FE 1t b THBJ CDJiJ E N SER L __ I1lfiH EMF CUT our SWITCH WHEN USED LrCTRIC CHOKE r I N _ _ Q _ _...

Страница 144: ...Q q ta I 0 I Q It l IJ j O 0 e l JJJl I rJ _ j o I JI w I Il t lII I I I 6 I i I _ c I I I a I i I I l I w I I I I I I I I Q I J lei I Jol l I al H j jJ lt I s OIL DRAIN HAUST OUTLET ADJUSTMENT FLp G...

Страница 145: ...FuE L SOL NOfD o CtRculHD l VAL VE 1 TO EN ft t N U6 q l TO GEt lERATOR B2 I I 1 1 0 5 fl c J 1 vOl T I 1m I L t T IC FUEL 1 _ BATT R IPLI WfP I PM LLEC r II I _ol I _L ____ 1 I M V 6ED r CHaME f I I...

Страница 146: ...e Revolving Field Residual Reset Switch Reverse Current Relay Revolving Armature Gener ator Armature Ball Bearing Brushes Commutator Field Commutator Collector Rings Resistor Charge Circuit Resistor E...

Страница 147: ...rnor Arm Governor Governor Governor Shaft Governor Shaft Bearings Governor Governor Ball Brg Governor Yoke Beat Exchanger Hi Temp Switch Ignition Breaker Points 1 Cylinder 2 Cylinder 4 Cylinder Igniti...

Страница 148: ...em 3 3 Ignition System 3 4 Governor System J 3 5 Oil System 3 6 Starting System 3 7 Cylinder Heads and Valves 3 8 Pistons Connecting Rods Cylinders 3 9 Engine Disassembly 4 GENERATOR REVOLVING FIELD 7...

Страница 149: ...tandard Model cification Letter Advanceswith ONANchanges r JB Some models have generators reconnectiblefor either e L 2 or 3 these models are designated 3C MJB MJC AllCode 3 models are reconnectible f...

Страница 150: ...s is what it was designed for But tion ONAN recommends that you study the whole It will help to acquaint you with the plants you ll ingon and save time later on in servicing If possible use a parts ca...

Страница 151: ...If you need help with your old Onan visit the Smart Guys at The Stak They have many years of experience and they are happy to help http www smokstak com forum forumdisplay php f 1...

Страница 152: ......

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