EH18V OHV - Subaru Industrial Power
Contents
1. 53 10 6 Engine Backfires Through Carburetor meme 53 11 INSTALLATION e nnne hne tenen 54 11 1 Installing ia 54 44 2 Ventilation em ee ke ere ooo span oen ene ene Re reta ees 54 11 3 Exhaust Gas Discharge eene 54 12 SERVICE DATA eene enne nnne nennen nennen nnne nenne 55 12 1 Clearance Data and Limits HH 55 12 2 Torque Specifications eme 61 12 3 Oil Grade Chart eem eene nennen nnne enne 61 13 MAINTENANCE AND STORAGE Henne enne 62 13 1 Daily Maintenance Every 8 Hours emm eene 62 13 2 Initial 20 Hours Maintenance emen 62 13 3 Every 50 Hours 10 Days Maintenance em 62 13 4 Every 100 200 Hours Monthly Maintenance mmm 63 13 5 Every 500 600 Hours Maintenance emen 63 13 6 Every 1000 Hours Yearly Maintenance 63 13 7 Engine Storage e 63 1 SPECIFICATIONS Air Cooled 4 Cycle Vertical Shaft Overhead Valve Gasoline Engine x 2 64 X 2 05 in Piston Displacement 183 cc 11 16 cu in Maximum Horsepower 4 4 3600 KW rpm i 6 3600 HP rpm 1 29 2700 kgm rpm sorg 9 3 2700 ft Ibs rpm Counterclockwise As Viewd From PTO Shaft Side Dry Weight 17 kg 37 5 lbs Dimensions Without P T O Shaft LxWxH 409 x 372 x 311 mm 16 10 x 14 65 X 12 24 in2. PISTON RING COMPRESSOR FLYWHEEL PULLER Fig 5 1 5 3 DISASSEMBLY PROCEDURES CLASSIC STEEL PRO POLY Spark plug Remove spark plug cap and spark plug Oil drain oil 1 Remove oil gauge filter and 2 Remove oil drain plug and drain oil bracket 3 Remove oil filter 4 Remove oil filter bracket M6X 12mm bolt 2pcs 19mm plug wrench 14mm box wrench 10mm box wrench OIL FILTER BRACKET OIL DRAIN PLUG STEP 2 M6 BOLT 2pcs Classic Steel SPARK PLUG 1 is Bo N P S p NW 2 3 Q M6 BOLT 2pcs OIL FILTER BRACKET OIL DRAIN PLUG STEP 2 Fig 5 2 Recoil starter 5 3 DISASSEMBLY PROCEDURES CLASSIC STEEL CONTINUED Remove recoil starter from engine 10mm box wrench bolt 4pcs 4 Fuel tank 1 Remove fuel tank M6 X 12mm bolt 2pcs 2 Remove fuel pipe from the fuel tank 3 Remove side guard 6 12mm bolt 2pcs 4 Remove bracket fuel tank 6 14mm bolt 16 5 Remove cover stop switch M6 FLANGE BOLT 5pcs RECOIL STARTER ASS Y TANK BAND 1 FUEL TANK M6 FLANGE BOLT 6pcs TANK BAND 2 HOSE CLAMP SIDE GUARD _ M6 FLANGE BOLT 5 3 13 5 3 DISASSEMBLY PROCEDURES CLASSIC STEEL CONTINUED w Air cleaner 1 Remove air cleaner c
3. Specifications and dimensions are subject to change without notice 2 PERFORMANCE 2 1 MAXIMUM OUTPUT The maximum output of an engine is such a standard power as produced by the engine with its throttle valve fully opened after its initial break in period when all the moving parts are properly worn in Therefore a new engine may not produce the maximum output in the beginning because the moving parts are not in a properly worn in condition 2 2 MAXIMUM TORQUE The maximum torque indicates the torque at the output shaft when the engine is producing the maximum output 2 3 PERFORMANCE CURVES e EH18V 5 22 7 0 4 48 6 0 Bose Sy els erp 1 3 73 4 5 0 2 98 ES 4 0 MAXIMUM HORSEPOMER 2 24 3 0 HORSEPOMER KW HP 1 i 1 1 1 I I 1 T 1 f 1 1 1 I I i 1 49 2 0 MAXIMUM TORQUE 1 3 N12 TORQUE F Kg m 1 1 2000 2400 2800 3200 3600 REVOLUTION rp m 3 1 8 FEATURES The overhead valve desis offers compactness light weight and ideal combustion characteristics resulting in more power from less fuel and prolonged engine life 2 The parts such as a large capacity muffler dual element air cleaner reduce noise to a minimum level 3 4 The muffler and carburetor are located on opposite sides making the arrangements for cooling air The automatic decompr
4. Rocker shaft outside dia Rocker arm hole dia Rocker arm shaft clearance VALVE SPRING FREE LENGTH 7 960 7 975 0 3134 0 3140 8 000 8 015 0 3150 0 3156 0 025 0 055 0 0010 0 0022 11 995 12 000 0 4722 0 4724 12 016 12 034 0 4731 0 4738 0 016 0 039 0 0006 0 0015 60 Unit mm in Unit mm in Valve cutter angle a Valve contact width b a 90 b 0 7 1 0 0 028 0 039 12 2 TORQUE SPECIFICATIONS TIGHTENING TORQUE DESCRIPTION 12 3 OIL GRADE CHART Spark plug Recommendedoilviscosityfortheembienttempartue Recommended oil viscosity for the embient temparature Multi ss grade 10 W 0 mem C Specified Lubricant Quality 20 10 0 10 20 30 40 Li 4 14 50 68 86 104 e Use oil classified as SC or higher Multi grade oil tends to increase its consumption at high ambient temperature 61 13 MAINTENANCE AND STORAGE The following maintenance jobs apply when the engine is operated correctly under normal conditions The indicated maintenance intervals are by no means guarantee maintenance free operations during these intervals For example if the engine is operated in extremely dusty conditions the air cleaner should be cleaned every day instead of every 50 hours 13 1 DAILY MAINTENANCE EVERY 8 HRS MAINTENANCE REMARKS REF
5. SERVICE EH18V OHV MANUAL ROBIN AMERICA INC ROBIN TO WISCONSIN ROBIN ENGINE MODEL CROSS REFERENCE LIST ROBIN WISCONSIN ROBIN SIDE VALVE EYOS W1 080 EY15 WI1 145 EY15V W1 145V EY20 Wi 185 EY20V 1 185 23 Wi 230 EY28 W1 280 EY35 W1 340 EY40 W1 390 45 W1 450V EY21 EY21W EY44 EY44W EY18 3 EY 18 3W EY25 EY25W EY27 EY27W OVERHEAD VALVE WOI 115 2 WO1 120 15 WO1 150 WO1 170 EH21 0 EH25 WO1 250 EH30 WO1 300 EH30V WO1 300V EH34 WO1 340 EH34V WO1 340V EH43V WO1 430V CYCLE EC13V WT1 125V DIESEL DY23 WRD 1 230 DY27 WRD1 270 DY30 WRD 1 300 DY35 WRD 1 350 DY41 WRD1 410 CONTENTS Section Title 1 SPECIFICATIONS 2 PERFORMANCE eee eee eene eene 2 2 1 Maximum Output 2 4 4 petente 2 2 2 Maximum Torque Hehe 2 2 3 Performance Curves A EE X 2 3 FEATURES ees E m 3 4 GENERAL DESCRIPTION OF ENGINE COMPONENTS 3 4 1 Cylinder and Crankcase mee eee 3 4 2 Main Bearing Cover hmmm 3 4 3 Crankshaft eem 4 4 4 Connecting Rod and Piston 27 4 5 ele DLL a esia sss 4 4 6 Valve Arrangement eher nnn isaeoqoooeusoooooqaaoqooooooqo s 5 4 7 Cylinder Head eed 7 5 4 8 Governor System s aided E baba MER ERU EH PERS LIRE 5 4 9 Cooling eH 6 4 10 Lubrica
6. guides in CYLINDER HEAD Refer to SERVICE DATA for clearance spec 2 ifications S VALVE SPRING After replacing the valves and guides lap RETAINER valves in place until a uniform ring shows COLLET around the face of the valve Clean valves and wash cylinder head thoroughly Fig 5 35 5 Install cylinder head to cylinder with new head gasket i NOTE When installing head gasket show Fig 5 36 Tighten three flange bolts and a flange nut evenly in three steps by the following tight ening torque Cylinder head M8 X 65 mm bolt 2 pcs M8 X 40 mm bolt gt 1 pce flange nut sesse 1 pce 72 fl 38 MAG SIDE Fig 5 36 5 4 10 ROCKER ARMS AND PUSH RODS 1 Insert push rods into crankcase Put push rod tip in the hollow of tappet top 2 Apply oil to the rocker arms and assemble them to the cylinder head using the rocker shaft and spacer 5 4 11 VALVE CLEARANCE ADJUSTMENT 1 Position the piston at the top dead center of the compression stroke The top dead center may be obtained by placing the key slot on the power take off shaft to 45 from the center of cylinder Fig 5 37 2 Loosen the lock nut on the rocker arm and turn the adjusting screw to adjust the clearance between the rocker arm and the valve stem end See Fig 5 38 Tighten the lock nut 0 085 0 115 mm 0 0034 0 0045 in NOTE Check and adjust valve clearance with engi
7. 1 pce 5 4 17 OIL FILLER Install oil filler to the engine M6 X 12 mm bolt 1 pce 5 4 18 CARBURETOR Install the gaskets insulator and carburetor S INSULATOR x E SID 9 ENGINE 7 GASKET INSULATOR 5 lt 0 GRAY GASKET 2 INSULATOR ORANGE CABURETOR Fig 5 42 M6 X 12mm BOLT 1pce BRACKET A C cover M6 x 12mm BOLT 2pcs M6 x 14mm BOLT 2pcs M6 x 14mm BOLT 3pcs BLOWER HOUSING i OIL FILLER BRACKET BRACKET 1 2 fuel tank M6 X 14mm BOLT 2pcs BLOWER HOUSING BRACKET 36 M6 14mm TAPPING BOLT 1pce Fig 5 41 Pro Poly 5 4 19 AIR CLEANER 1 Install cleaner base on studs install bracket cleaner Tighten the clamp for stop switch wire together with cleaner bracket on crankcase side M6 Nut 2pcs Tightening torque 8 9 5 Nem 80 100 kg cm 6 7 SLOW AIR BLEED JET AIR VENT HOLE NOTE Attach the air cleaner gasket to the carburetor flange when installing air cleaner base on engine See Fig 5 43 MAIN AIR BLEED JET 2 Install cover and element to the air cleaner base M6 wing bolt 1pce 3 Connect a breather pipe between breather and air cleaner Fig 5 43 5 4 20 GOVERNOR ADJUSTMENT For correct carburetor throttle opening and gov ernor regulation the governor lever must be pro pe
8. Fig 5 18 crankshaft M6x30mm bolt and washer assy e 8 5 21 Oil pump 1 Remove oil pump cover from main bearing 10mm box wrench cover 6 12mm bolt 4pcs 2 Remove oil pump and oil pump Outer Fig 5 18 MAIN BEARING COVER OIL PUMP INNER OIL PUMP OUTER EB B D eon cansa BOE Na O RING D WASHER ASSY 8pcs M6 x 12mm BOLT 4pcs Fig 5 19 24 22 Camshaft and 1 Remove camshaft from crankcase To prevent the tappets tappets See Fig 5 20 from getting damages put 2 Remove tappets from crankcase the crankcase cylinder side down See Fig 5 20 Tappet must be installed in their original position Mark tappets prior to re moval to prevent error i CAMSHAFT 1 D Fig 5 21 Fig 5 20 95 Connecting 1 Remove connecting rod bolts Scrape off all carbon 10mm box wrench rod and connecting rod cap deposits that might piston Connecting rod bolt 2pcs interfere with removal of 2 Turn crankshaft until piston is at top dead piston from upper end of center push out connecting rod and piston cylinder assembly through top of cylinder 3 Remove clips and piston pin to remove connecting rod from piston 4 Remove piston rings from piston Ring expander CLIP CONNECTING ROD PISTON PIN CONNECTING ROD 2pcs PISTON RING DIES pes C
9. M6X12mm bolt 4pcs 2 Loosen lock nut for rocker arm adjusting screw M8 lock nut 2pcs 3 Slide off rocker arm shaft from the holder to the flywheel side remove rocker arms See Fig 5 15 4 Remove push rods 5 Remove cylinder head and gasket M8 x65mm bolt 2pcs M8X40mm bolt 1pce M8 flange nut gt Ipce 12mm box wrench 12mm box wrench CYLINDER BAFFLE ROCKER ARM SHAFT M8 BOLT 2pcs M8 BOLT 1 lt ROCKER ARM LOCK NUT 2pcs ADJUSTING SCREW STEP 17 Fig 5 14 Fig 5 15 Intake and 1 Press down spring retainer and slide it to Clean carbon and gum exhaust valve release from the groove of valve stem deposits from the valves then remove spring retainer and valve valve seats ports and spring See Fig 5 16 guides Inspect valves 2 Remove intake and exhaust valves from valve seats and guides cylinder head 19 Breather 1 Remove breather cover 10mm box wrench M6 X 12mm bolt 2pcs Remove gasket tappet cover breather plate and gasket breather plate _ INTAKE VALVE EXHAUST VALVE BREATHER PLATE GASKET TAPPET COVER M6 x 12mm BOLT 2pcs amp k Fig 5 17 VALVE SPRING RETAINER Fig 5 16 23 RN _ Main bearing 1 Remove main bearing cover Do not lose spacer for 10mm box wrench cover See
10. can easily be supplied and checked the spark plug can easily be checked the air cleaner can easily be serviced and that the oil can easily be discharged 11 2 VENTILATION Fresh air is necessary for cooling the engine and burning the fuel In the case the engine is operated under a hood or in a small room temperature rise in the engine room can cause vapor lock oil deterioration increased oil consumption loss of power piston seizure shorter engine life etc making it impossible to operate the engine properly It is necessary therefore to provide a duct or baffle to guide cooling air to the engine to prevent recirculation of the hot air used for engine cooling and temperature rise of the machine Keep the engine room temperature below 50 C even in the hottest period of the year 11 3 EXHAUST GAS DISCHARGE Exhaust gas is noxious When operating the engine indoors be sure to discharge the exhaust gas outdoors If a long exhaust pipe is used in such a case the internal resistance increases causing loss of engine power Thus pipe inside diameter must be increased in proportion to exhaust pipe length Exhaust pipe Less than 3m long pipe inside diameter 25 mm Less than 5m long pipe inside diameter 30 mm 54 12 SERVICE DATA STD in the following table is the parts dimension from the brand new engine or the spare parts Whereas Limit shows the maximum allowance for the parts to be used on the engine If the measureme
11. gear with timing mark on camshaft and install camshaft in the 4 crankcase See Fig 5 31 CAUTION Incorrect valve timing will cause engine s malfunction TIMING MARKS 2 CAMSHAFT CRANKSHAFT Fig 5 31 90 5 4 6 ADJUST CRANKSHAFT END PLAY 1 Adjust end play to the specified values using the proper spacer The proper spacer may be determined by the following manner MAIN BEARING COVER CRANKCASE 5 32 CRANKSHAFT END PLAY 1 Measure the depth 1 From the mating surface to the inner race of the ball bearing 2 Measure height B1 From the mating to the crank gear A1 0 3 B1 SIDE CLEARANCE mm SIDE CLEARANCE 0 2 THICKNESS OF CRANKSHAFT SHIM mm A 0 012 B1 SIDE CLEARANCE in SIDE CLEARANCE 0 008 THICKNESS OF CRANKSHAFT SHIM in Following are available spacer shims 0 6 mm 0 024 T 0 8 mm 0 031 1 0 mm 0 039 SPACER SHIMS 5 4 7 MAIN BEARING COVER 1 Install oil pump to the main bearing cover M6 X 12mm 4 pcs Tightening torque 8 9 5 Nem 80 100 kgecm 6 7 ftelb 2 Lubricate the oil seal and bearing sur faces Add a light film of oil on the main bearing cover face to hold the gasket in place Place spacers chosen at procedure 5 4 6 on crankshaft Use an oil seal guide when installing the main bearing cover to avoid damaging the seal Tap the cover into plac
12. removing the throttle stop screw 20 Exercise care not to damage throttle valve ends 8 2 2 CHOKE SYSTEM 1 Remove the clip 23 and choke valve 17 and pull out the choke shaft 16 2 When reassembling the choke shaft make sure that the cutout in the choke valve faces the main air jet 8 2 3 PILOT SYSTEM 1 Remove the pilot jet 18 using correct tool to avoid damage to it 2 Reassembly Tighten the pilot jet securely Otherwise the fuel may leak causing engine malfunction 11 Fig 8 3 45 8 2 4 MAIN SYSTEM 1 Remove the bolt 11 and take out float chamber body 5 2 From the body 3 remove the main jet 9 3 Reassembly Fasten the main jet securely to the body Otherwise the fuel may become too rich and cause engine malfunction b The bolt tightening torque is 80 kg cm 8 2 5 FLOAT SYSTEM 1 Pull out the float pin 8 and remove the float 7 and needle valve 6 When cleaning the jets use neither a drill nor a wire because of possible damage to the orifice which will adversely affect fuel flow Be sure to use compressed air to blow them clean 2 When removing the needle valve and floats gently tap the reverse side using the rod more slender than the float pin and remove since the float pin is calked to the carburetor body 5 46 9 STARTING SYSTEM 9 1 RECOIL STARTER When repairing recoil starter disassemble and re assemble in the fol
13. tachometer or a revolution counter Correct engine speed is 3350 r p m 5 Loosen the bolts B and C Move the speed control bracket to the position where the engine speed become 3350 r p m In order to reduce the engine speed move the speed control bracket to the left 6 After adjusting the engine speed re tighten the two bolts B and C to fix the bracket 7 Tighten the adjusting screw until it contacts the choke lever CHOKE LEVER A ROD SPRING SPEED CONTROL LEVER SCREW PAN HEAD SPEED CONTROL BRACKET When speed control bracket is moved in the direction of the arrow engine speed is reduced Fig 5 47 39 5 5 BREAK IN OPERATION An engine that has been completely overhauled by being fitted with a new piston rings valves and connecting rod should be thoroughly RUN IN before being put back into service Good bearing surfaces and running clearances between the various parts can only be established by operating the engine under reduced speed and loads for a short period of time While the engine is being tested check for oil leaks Make final carburetor adjustment and regulate the engine operating speed mew 1 40 6 MAGNETO 6 1 FLYWHEEL MAGNETO The ignition system of the EH18V is a pointless flywheel magneto with an automatic advancing characteristic Being different from the breaker point type ignition system this system is completely free from s
14. 0008 0 0023 Piston ring end gap 0 05 0 25 0 0020 0 098 0 3 0 9 0 0118 0 0354 57 Unit mm in CONNECTING ROD Big end inside dia 26 000 26 013 26 1 1 0236 1 0241 1 1850 Clearance between big end and crankpin 0 2 0 008 14 08 06331 0 12 0 0047 Big end side clearance 0 1 0 3 0 5 0 0039 0 0118 0 040 CRANKSHAFT 9 Crankpin outside dia 2 25 950 25 963 25 84 1 0217 1 0221 1 1752 0 5 0 037 0 063 0 0015 0 0024 Small end inside dia 14 010 14 021 0 5516 0 5520 Clearance between small end and piston pin 0 010 0 029 0 0004 0 0011 a D1 D2 24 988 24 997 0 9838 0 9841 58 CAMSHAFT Cam height Ql Journal outside dia D type VALVE Valve stem outside dia Clearance between valve stem dia and valve guide Valve clearance 29 6 29 8 1 165 1 173 16 973 16 984 0 6682 0 6687 14 973 14 984 0 5895 0 5899 5 440 5 455 0 2142 0 2148 5 426 5 444 0 2136 0 2143 0 045 0 078 0 0018 0 0031 0 056 0 092 0 0022 0 0036 0 085 0 115 0 0033 0 0045 Unit mm in 14 95 0 5886 5 35 0 2106 5 35 0 2106 0 3 0 012 0 3 0 012 TAPPET Stem outside dia Guide inside dia Tappet guide clearance ROCKER ARM
15. ER 1 Clean away dust and chaff from engine 22 linkage is especially sensitive dius instruction for 3 Inspect for loose hardware Loose bolts and nuts may come off and Read instruction for retighten if necessary result in breakage of other parts use 4 Check oil level and add to full mark Instruction for 13 2 INITIAL 20 HOURS MAINTENANCE REMARKS REFER Read instruction for 1 Change crankcase oil To remove sludge from run in operation ise 13 3 EVERY 50 HOURS 10 DAYS MAINTENANCE MAINTENANCE REMARKS REFER 1 Change crankcase oil Contaminated oil quickens wear i instruction for 3 Check and clean spark plug 2 in gasoline or polish with jon instruction for 62 2 Check fuel leakage from fuel system If any retighten fasteners or replace necessary parts Read instruction for use O 13 4 EVERY 100 200 HOURS MONTHLY MAINTENANCE MAINTENANCE REMARKS REFER 1 Inspect cooling system and remove dirt Remove blower housing and clean up Consult your nearest and chaff between fins and housing Robin dearer d i i 1 13 5 EVERY 500 600 HOURS MAINTENANCE MAINTENANCE REMARKS REFER Carbon deposits in combustion chamber Consult your nearest 1 Remove carbon from cylinder head causes lack of power Consult your nearest Robin dearer 3 Clean fuel tank Can LI au Raren Consult your nearest Consult
16. ONNECTING ROD CAP 6 6 2 5 SPACER Fig 5 23 26 d 5 4 REASSEMBLY PROCEDURES PRECAUTIONS FOR REASSEMBLY 1 Clean parts thoroughly before reassembly Pay utmost attention to cleanliness of piston cylinder crankshaft connecting rod and bearings 2 Scrape off all carbon deposits from cylinder head piston top and piston ring grooves 3 Check lip of oil seals Replace oil seal if the lip is damaged Apply oil to the lip before reassembly 4 Replace all the gaskets with new ones 5 Replace keys pins bolts nuts etc if necessary 6 Torque bolts and nuts to specification referring to page 59 12 2 TORQUE SPECIFICATIONS 7 Apply oil to rotating and sliding portions 8 Check and adjust clearances and end plays where specified in this manual 5 4 1 CRANKSHAFT 1 Install crankshaft on crankcase using an oil seal guide to avoid damage to crankshaft oil OIL SEAL GUIDE seal See Fig 5 24 CRANKSHAFT Fig 5 24 27 5 4 2 PISTON AND PISTON RINGS 1 Install oil ring first then second ring and top ring Spread ring only far enough to slip over piston and into correct groove Use care not to distort ring See Fig 5 26 5 4 3 PISTON AND CONNECTING ROD Install piston on connection rod Oil the small end of connecting rod before instal ling piston and piston pin Use clips on both side of the piston pin to secure piston pin in position TOP RING SECOND
17. RING OIL RING Fig 5 25 OPEN ENDS OF PISTON RING Fig 5 26 28 5 4 4 CONNECTING ROD 1 Before installing the piston and connecting rod SECOND RING in the cylinder oil the piston piston rings and BAS cylinder wall z F OIL RING 2 Stagger the piston ring gaps 90 apart around the piston See Fig 5 28 90 Use a piston ring compressor when installing 5 M piston Install piston and rod with the marks on 47 90 flywheel side of the crankcase See Fig 29 T d 3 Turn crankshaft to bottom dead center then tap uem TOP RING lightly top of the piston until large end of the connecting rod meets crank pin Fig 5 28 PISTON RING COMPRESSOR CRANKCASE FLYWHEEL SIDE 4 Install connecting rod cap with the match mark on the main bearing cover side Match this mark with the one on the left side of con necting rod s large end viewed from main bearing cover side See Fig 30 Connecting rod bolt 2 pcs Tightening torque 17 20 Nem 170 200 kg cm 12 2 14 5 pA ALIGNMENT MARK NOTE Fig 5 30 Check for free movemont of connecting rod by turning crankshaft slowly 29 5 4 5 TAPPET AND CAMSHAFT 1 Oil tappets and install in their original position Push in fully to avoid damage during camshaft installation 2 Lubricate bearing surfaces of camshaft a Align timing mark on crankshaft
18. TCHET GUIDE SET SCREW Fig 9 7 Classic Steel Pro Poly Fig 9 8 6 7 8 Test the operation of the recoil starter to see if the rope recoils satisfactorily and the ratchets project and retract properly Mount the recoil starter to the engine If the spring escapes from the reel when disassembling the recoil hook the outer end of the spring onto the notch of the reel and rewind the spring into the housing Lubricate the rotating parts sliding parts and spring with heat resistant grease or mobile oil when reassembling the recoil and prior to long term storage 50 10 TROUBLESHOOTING The following three conditions must be fulfilled for satisfactory engine start 1 cylinder filled with a proper fuel air mixture 2 Good compression in the cylinder 3 Good spark properly timed to ignite the mixture The engine cannot be started unless these three conditions are met There are also other factors which make engine start difficult e g a heavy load on the engine when it is about to start at low speed and a high back pressure due to a long exhaust pipe The most common causes of engine troubles are given below 10 1 STARTING DIFFICULTIES 10 1 1 FUEL SYSTEM 1 No gasoline in the fuel tank or the fuel cock closed 2 The carburetor is not choked sufficiently especially when the engine is cold 3 Water dust or gum in the gasoline interfering the fuel flow to the carbure
19. UBRICATION EH18V has a trochoid pump outside the main bearing cover that is driven by the camshaft EH18V uses forced splash type lubrication See Fig 4 9 CAMSHAFT M6 FLANGE BOLT 1pce OIL SHELTER PLATE MAIN BEARING COVER OIL PUMP INNER OIL PUMP OUTER OIL PUMP COVER I M6 FLANGE BOLT 4pcs Fig 4 9 4 11 IGNITION SYSTEM The ignition system is a transistor controlled magneto ignition system which consists of a fly wheel and an ignition coil with a built in transistor mounted on the crankcase This system has an automatic ignition timing advancing for easier starting See Fig 4 10 For details refer to page 39 section 6 4 12 CARBURETOR The engines are equipped with a horizontal draft carburetor that has a float controlled fuel system and a fixed main jet The carburetors are calibrated carefully for the sure starting good acceleration low fuel con sumption and sufficient output For the datails refer to page 42 section 8 CARBURETOR See Fig 4 11 4 13 AIR CLEANER air cleaner is a heavy duty type with a dual element system See Fig 4 12 FLYWHEEL WING BOLT CLEANER COVER Nec PRIMARY ELEMENT GROMMET URETHANE FOAM eee lt i SS IS CONDARY ELEMENT s Fig 4 12 4 14 DECOMPRESSION SYSTEM An automatic decompression mechanism which opens exhaust valve before
20. an aluminum alloy casting and carries two compression rings and one oil ring See Fig 4 4 4 5 CAMSHAFT The camshaft is a hollow shaped and made of special cast iron with the camshaft gear casted together A centrifugal decompression lever is assembled on the camshaft The lubrication oil pump is driven by the groove on the end of the camshaft See Fig 4 5 Fig 4 3 Fig 4 4 Fig 4 5 CRANKSHAFT GEAR 4 6 VALVE ARRANGEMENT The intake valve is located at flywheel side of the cylinder head Hard alloy valve seats are molded in the cylinder head and stellite is fused to the exhaust valve face The cylinder baffle leads cooling air to the exhaust valve area for the optimum cooling See Fig 4 6 4 7 CYLINDER HEAD The cylinder head is an aluminum die casting which utilizes wedge type combustion chamber for the highest combustion efficiency See Fig 4 7 4 8 GOVERNOR SYSTEM The governor is a centrifugal flyweight type which ensures constant operation at the selected speed against load variations The governor gear with governor weights is in stalled on the bearing cover and driven by the camshaft gear See Fig 4 8 FLYWEIGHT 2 GOVERNOR SLEEVE Fig 4 8 4 9 COOLING SYSTEM The large fins on the flywheel provide sufficient cooling air capacity for the inlet and exhaust area and cylinder The cylinder baffle helps the cooling air flow efficiently 4 10 L
21. bolt gt gt gt 4pcs 2 Connect fuel pipe between fuel cock and carburetor 5 4 24 OIL FILTER BRACKET AND OIL FILTER 1 Install oil filter bracket X 12 mm bolt 2pcs Tightening torque 8 9 5 N m 80 100 kg cm 6 7 ftelb 2 Tighten filter using a proper tool about 3 4 turn OIL FILTER BRACKET OIL FILTER after gasket contacts mounting surface of engine Fig 5 46 NOTE Check for leaks at test running after engine assembly is completed 38 5 4 25 SPARK PLUG 1 Install spark plug to the cylinder head 7 Spark plug CHAMPION L86C Tightening torque New spark plug Retightening 118 147 Nem 22 6 26 5 N m 120 150 kg cm 230 270 8 7 10 9 ft lb 16 6 19 5 ft lb 2 Connect spark plug cap to the spark plug 5 4 26 ENGINE OIL After complete reassembly turn the engine over and pull the recoil starter to check for any abnormal conditions or loose fitting parts Review and check wiring Fill crankcase with correct grade of oil See page 59 GRADE CHART Crankcase oil capacity 500cc 5 4 27 CHOKE AND SPEED ADJUSTMENT 1 Start the engine Operate the engine without load 2 In order to fix the position of the speed control lever insert a philips screw driver into the hole A of the speed control lever through the hole of the speed control bracket 3 Loosen the adjusting screw on the speed control lever 4 Check the engine speed by a
22. ches the ignition timing the ignition timing control circuit for the higher engine speed is activated and provides the base current I to the power transistor This current induces the collector current I and will bypass the current I to shut down the current L abruptly because the power transistor is turned off This sudden current change generates a big voltage on the secondary side of the ignition coil causing sparks at the spark plug The ignition timing control circuit for the higher engine speed is activated sooner than the control circuit for the lower speed and not activated when the engine speed is in a lower range Resister Low Speed lgnition Timing Control Circuit Primary Coil Primary Coil Spark Plug Automatic Advancing Control Circuit Signal Transistor A Ignition Coil 6 3 WIRING DIAGRAM STANDARD Spark plug ELECTRONIC ADVANCING FLYWHEEL B T D C MAGNETO SYSTEM 23 2 5 STEP ADVANCING 2 E z 9 15 500 1000 2000 3000 r p m ENGINE REVOLUTION Fig 6 2 Stop switch Ignition coil Connector Black Flywheel Fig 6 3 42 0 7 AUTOMATIC DECOMPRESSION SYSTEM The decompression system operates to release compression by lifting up the exhaust valve at starting The release lever mounted on the camshaft has a flyweight at one end and a crescent cam at the other _ end When starting the engine the crescen
23. djust the position of inner end of the spring so it hooks on hook in the starter case securely The shape of starter spring inner end may be Lz adjusted with a plier if necessary I OUTER END OF SPRING SPRING KEEPER y INNER END OF SPRING Fig 9 5 BEARING REEL 48 3 Prior to installing the reel in the starter case wind the starter rope in the reel for 2 5 turns in the arrowhead direction as shown in Fig 9 6 Then let the rope out of the reel from the reel notch Line up the reel hook with the inner end of the spring and install the reel in the starter case Check that the inner end of spring is securely hooked onto the hook 4 Reassemble the parts in reverse order of disas sembly Check that the ratchets are pushed by the ratchet springs toward the center of the recoil Install the friction plate with its two bosses set inside of the bent portion of ratchets Apply small amount of lock tight to the center screw and torque it Thightening torque 5 Hold starter rope as shown in Fig 9 8 and turn reel 4 times in the arrowhead direction Firmly press the reel not to allow reverse turn and pull starting knob to let starter rope out of starter case Return knob slowly to let starter rope rewind in reel 49 Classic Steel Classic Steel FRICTION SPRING 669 ree GUIDE SET SCREW QD 4 FRICTION SPRING RA
24. e with a soft ham mer Main bearing cover M6 X 30 mm bolt and washer 8 pcs Tightening torque 8 9 5 Nem 80 100 kg cm 6 7 16 CRANKCASE O RING OIL PUMP COVER gt M6 BOLT 4 amp Fig 5 33 32 CAMSHAFT M6 BOLT AND WASHER ASS Y 8pcs 5 4 8 BREATHER VALVE Attach breather plate breather valve and breather I I 25 2 2 Of GASKET i BREATHER PLATE GRAY cover to crankcase using proper gaskets See Fig 5 34 Replace gaskets with new ones if they are torn or damaged Replace breather hose at least once a year or when ever a crack was found I UE gt BREATHER BREATHER PLATE GASKET TAPPET COVER LIGHT GREEN Fig 5 34 5 4 9 CYLINDER HEAD 1 Clean carbon and gum deposits from the valves seats ports and guides Inspect the valves valve seats and valve guides 2 Replace valves that are badly burned pitted or warped I 3 When installing the valves in the cylinder head oil the valve stems and insert them into the valve guide Then place the cylinder head on a flat table install the washer valve spring and spring retainer See Fig 5 35 4 Valve guides should be replaced when the valve stem clearance exceeds specifications See SERVICE DATA page 57 Draw the valve guides out and press the new INTAKE VALVE
25. ession system offers easy and sure starting flow much easier in the design of power equipment The oil pump and oil filter provide excellent lubrication regardless of engine posture during operation This engine is offered in two stylish versions The Pro Poly version engine is covered with a stylishly designed shroud with the fuel tank incoroprated into it The Classic Steel version does not have the shroud or combined fuel tank 4 GENERAL DESCRIPTION OF ENGINE COMPONENTS 4 1 CYLINDER AND CRANKCASE The cylinder and crankcase is single piece alu minum diecasting The cylinder liner made of special cast iron is molded into the aluminum casting The crankcase has a mounting surface on the output shaft side where the main bearing cover is attached See Fig 4 1 4 2 MAIN BEARING COVER The main bearing cover is an aluminum diecasting which is mounted on the output shaft side of the crankcase Remove the main bearing cover to inspect inside of the engine The main bearing cover also functions as an oil pan with a trochoid oil pump and oil filler See Fig 4 2 Fig 4 2 4 3 CRANKSHAFT The crankshaft is a forged carbon steel and the crank pin is induction hardened The PTO end of the shaft has a crankshaft gear which is pressed into position See Fig 4 3 4 4 CONNECTING ROD AND PISTON The connecting rod is a forged aluminum alloy and its large and small ends function as bearings The piston is
26. g from the hausing crankcase M6 X 12mm bolt 2pcs M6 X I 4mm bolt I pce Ignition coil 1 Disconnect stop switch wire from stop switch 2 Remove ignition coil from crankcase 10mm box wrench M6 x 30mm bolt 2pcs M6 X 12mm 8 M6 x 14mm Sort aes M6 x 12mm BOLT 2pcs BRACKET filler OIL FILLER CLAMP filler M6 x 30mm BOLT BS 2pcs A M6 12mm BOLT 1pce a Flywheel 1 Remove starter pully from flywheel 18mm box wrench M14 Ipce 2 Remove flywheel from crankshaft See Fig 5 11 3 Remove key from crankshaft driver M14 NUT 1pce YT 69 STARTER PULLEY FLYWHEEL Fig 5 11 Fig 5 9 Fig 5 12 20 m o mmm _ Qor A qoe 15 Brake assy 1 Remove brake assy M6X 12mm bolt 4pcs 4pcs M6 x 12mm BOLT SY Qe 3 Y BRAKE ASSY STEP 15 Fig 5 13 21 16 Cylinder 1 Remove cylinder baffle 10mm box wrench 8 bolt 1 pce 17 Cylinder head ROCKER COVER M6 x 12mm BOLT ET P uc 4pcs lt 1 Remove rocker cover and guide plate 10mm box wrench from cylinder head
27. hroud M6X 12mm bolt Ipce 4 Remove bracket A C cover M6xX 14mm bolt 6 14mm tapping bolt 1pce 10mm box wrench 10mm box wrench 4 M5 x 16mm TAPPING SCREW 2pcs TOP COVER RECOIL STARTER STEP 4 pee M6 x 12mm BOLT 4pcs N ENGINE SHROUD AIR CLEANER COVER M6 WING M6 x 14mm BOLT tpce BOLT tpe WE Y BRACKET A C cover M6 x 14mm TAPPING BOLT 1pce HOSE CLAMP FUEL HOSE 5 3 DISASSEMBLY PROCEDURES PRO POLY CONTINUED nes Air cleaner 1 Remove air cleaner element M6 wing bolt Ipce 2 Remove breather hose from cleaner base and crankcase 3 Remove air cleaner base from air cleaner bracket M6X 12mm bolt Ipce 4 Remove cleaner base and gasket air cleaner from carburetor M6 nut 2pcs 5 Remove bracket A C from the engine 16 12mm bolt Ipce 10mm box wrench 10mm box wrench 10mm box wrench M6 WING BOLT 1pce AIR CLEANER ELEMENT amp GROMMET or BRACKET air cleaner HOSE CLAMP STEP 6 M6 2pcs BREATHER HOSE Fig 5 4 16 5 3 DISASSEMBLY PROCEDURES CLASSIC STEEL PRO POLY Step Partto remove Procedures I 7 Speed control 1 Remove speed control assembly from the crank case then rem
28. lowing procedures Tools Socket wrench Needle nose pliers Screw driver 9 1 1 HOW TO DISASSEMBLY 1 Remove recoil starter from engine 2 Pull starter knob and pull out starter rope for 30 40cm to line up notch on reel with outlet hole for starter rope Hold reel with thumb and pull starter rope inside the starter case with screw driver See Fig 9 1 or 9 2 Rewind reel clockwise until the rotation stops When rewinding the reel control the rotation by holding starter rope using the notch on the reel and pressing the reel with thumb 3 Remove parts in the following order 1 Return spring 2 Rachet 3 Friction spring 4 Rachet guide S Set screw STARTER 7 Fig 9 2 Pro Poly 47 4 Remove the reel from the starter case as shown in Fig 9 3 Take out the reel slowly turning it lightly towards the left and right to remove spring from the hook Do not remove the reel quickly or the spring may escape from the starter case Untie the starter rope from the knob and remove Classic Steel 4 STARTER CASE Z Pro Poly 9 1 2 HOW TO REASSEMBLE 1 Put the starter rope through the starter knob and tie it as shown in Fig 9 4 Tie the rope tightly for the safety sake Put the opposite side of the rope through the starter case and reel Tie it in the same way as the starter knob end and put the knot in the reel completely Fig 9 4 2 Check that the spring is securely set in the reel A
29. metered and mixed with the air metered by the pilot air jet The fuel air mixture is fed to the engine through the pilot outlet and the bypass At idling speed the fuel is mainly fed from the pilot outlet 8 1 3 MAIN SYSTEM The main system feeds the fuel to the engine at medium and high speed operation The fuel is metered by the main jet and fed to the main nozzle The air metered by the main air jet is mixed with the fuel through the bleed holes in the main nozzle and the mixture is atomized out of the main bore It is mixed again with the air taken through the air cleaner into an optimum fuel air mixture which is supplied to the engine 8 1 4 CHOKE The choke is used for easy start when engine is cold When the starter is operated with a closed choke the negative pressure applied to the main nozzle increases and draws much fuel accordingly thus easily start up the engine 8 2 DISASSEMBLY AND REASSEMBLY Apart from mechanical failures most of carburetor troubles are caused by an incorrect mixing ratio which may arise mainly due to a clogged up air or fuel passage in jets or fuel level variations In order to assure proper flow of air and fuel the carburetor must be kept clean at all times The carburetor disassembly and reassembly procedures are as follows See Fig 82 8 2 1 THROTTLE SYSTEM 1 Remove the philips screw 15 and throttle valve 14 and pull out the throttle shaft 13 2 The spring 19 can be taken out by
30. ne cold Check operation of valves by turning crankshaft Remeasure valve clearance 3 Install guide plate and rocker cover using a gasket M6 X 12 mm bolt 4 pcs 34 5 4 12 BRAKE ASSEMBLY Install brake assy to the engine M6 X 12 mm bolt 4 pcs 8 9 5 Nem 80 100 kgecm 6 7 ftelb Never apply oil or grease on the internal of flywheel and brake 5 4 13 FLYWHEEL MAGNETO 1 Put the woodruff key in the key way of crank shaft Wipe off oil and de grease thoroughly from the tapered portion of the crankshaft and the fly wheel center hole 2 Pull the brake lever 3 Install the flywheel to crankshaft Tighten the flywheel nut with the starter pulley See Fig 5 39 Tightening torque i 59 63 Nem 600 650 43 47 ft lb 5 4 14 IGNITION COIL Install the ignition coil to the crankcase Adjust the air gap between the ignition coil and the flywheel using a thickness gauge filler gauge and tighten the bolts See Fig 5 40 M6 X 30 mm bolt 2 pcs 0 3 0 5 mm 0 012 0 020 in 35 FLYWHEEL Fig 5 39 Fig 5 40 5 4 15 BLOWER HOUSING AND BRACKETS Install blower hosing oil filler bracket fuel tank and air cleaner bracket Classic Steel M6 X 12 mm bolt 1 pce X 14 mm bolt 3 pcs Pro Poly M6 X 12 mm bolt 2 pcs M6 X 14 mm bolt 2 pcs 5 4 16 CYLINDER BAFFLE Install cylinder baffle M6 X 8 mm bolt
31. nt exceeds beyond the Limit the part needs to be replaced and or repaired 12 1 CLEARANCE DATA AND LIMITS Unit mm in CYLINDER HEAD Flatness LESS THAN 0 05 0 002 Valve seat contact width 0 7 1 0 0 028 0 039 Valve guide inside dia 5 500 5 518 5 65 0 2165 0 2172 0 2224 55 ITEM CYLINDER Inside dia Roundiness after reboring Cylindricity after reboring PISTON Piston size At skirt in thrust direction 1st reboring 2nd reboring 67 000 67 019 2 6378 2 6385 67 250 67 269 2 6476 2 6484 67 500 67 519 2 6575 2 6582 LESS THAN 0 01 0 004 LESS THAN 0 015 0 0006 66 96 66 98 2 6362 2 6370 67 21 67 23 2 6461 2 6469 67 46 67 48 2 6559 2 6567 56 Unit mm in To be rebored when the difference between max and min of diameter reached to 0 1 0 004 Uni mm in ITEM STD Limit 9 Ring groove side clearance 0 050 0 095 0 16 P 0 0019 0 0037 0 006 0 040 0 085 0 16 0 0016 0 0030 0 006 enu 0 0 035 0 12 9 0 0 0014 0 006 13 991 14 002 14 035 0 5508 0 5513 0 6313 13 992 14 000 13 960 0 5508 0 5512 0 6284 0 23 0 010 1 3 0 0091 2 1 0 0591 9 Piston pin hole Piston pin outside dia ox Clearance between piston and cylinder at skirt area 0 020 0 059 0
32. oaded 4 Cooling air circulation restricted 5 Cooling air path misdirected causes loss of cooling efficiency 6 Cylinder head cooling fins clogged up with dirt 7 Engine operated in an enclosed space without sufficient cooling air 8 Exhaust gas discharge restricted or carbon deposits in the combustion chamber 9 Engine running on low octane gasoline detonates due to heavy load at low speed 52 10 5 ENGINE KNOCKS 1 Poor quality gasoline 2 Engine operating under heavy load at iow saved 3 Carbon or lead deposits in the cylinder head 4 Spark timing incorrect 5 Loose connecting rod bearing due to wear 6 Loose piston pin due to wear 7 Engine overheated 10 6 ENGINE BACKFIRES THROUGH CARBURETOR 1 Water or dirt in gasoline or low grade gasoline 2 Intake valve stuck 3 Valves overheated or hot carbon particles in the combustion chamber 4 Engine cold 53 11 INSTALLATION Engine life ease of maintenance and inspection frequency of checks and repairs and operating cost all depend on the way in which the engine is installed Carefully observe the following instructions for installing the engine 11 1 INSTALLING When mounting the engine carefully examine its position the method of connecting it to a machine the foundation and the method of supporting the engine When determining its mounting position in particular make sure that gasoline and oil
33. ove governor spring from the governor lever M6X 12mm bolt 2pcs 2 Remove choke rod from speed control assembly then remove choke rod from choke shaft of the carburetor governor lever then remove rod spring and governor rod from throttle shaft of the carburetor Governor 1 Remove governor lever from the governor 10mm box wrench lever shaft 6 25mm bolt and washer assy Ipce 2 Remove rod spring and governor rod from SPEED CONTROL LEVER M6 x 12mm CHOKE ROD BOLT 2pcs GOVERNOR SPRING b e GOVERNOR LEVER ROD SPRING STEP 8 M6 x 25mm BOLT AND G WASHER ASSY 1pce OVERNOR ROD EN Fig 5 5 7 Partto remove Procedures Carburetor 1 Remove carburetor from stud bolts 2 Remove gasket and insulator from stud s n bolts Muffler 1 Remove muffler cover from muffler driver 5 lt 10mm tapping screw 3pcs 2 Remove muffler and gasket muffler 12mm box wrench M8 X70mm bolt and washer assy 2pcs 8 16mm bolt and washer assy M5 x 10mm TAPPING SCREW 3pcs VER 8 x 16mm BOLT AND P MUFFLER GASKET 8 x 70mm BOLT AND WASHER ASSY 2pcs GASKET INSULATOR INSULATOR SS GASKET 2 INSULATOR wee NX CARBURETOR Fig 5 7 18 Remove the clamp from oil filler and remove oil filler bracket M6 x 12mm bolt Ipce Blower Remove the blower housin
34. over and air cleaner element PROCEED TO STEP 7 OF DISASSEMBLY PROCEDURES M6 wing bolt I pce 2 Remove breather hose from cleaner base and crankcase 3 Remove air cleaner base from air cleaner bracket 6 12mm bolt Ipce 4 Remove cleaner base and gasket air cleaner from carburetor M6 nut 2pcs 5 Remove bracket A C from the engine M X 12mm bolt Ipce 6 Remove bracket A C cover 6 14mm bolt Ipce 6 14mm tapping bolt I pce 10mm box wrench 10mm box wrench 10mm box wrench 10mm box wrench M6 WING BOLT 1pce AIR CLEANER ELEMENT M6 X 14mm TAPPING 1pce Pd 2 Y BRACKET BOLT L 8 air cleaner 6 pout AIR CLEANER BASE dar STEP 5 Mp ma STEP 5 HOSE CLAMP J M6 NUT 2pcs 2 BREATHER HOSE B X 5 3 DISASSEMBLY PROCEDURES PRO POLY CONTINUED sofrem c NN 3 Top cover Remove top cover from the engine driver 5 16mm tapping screw 2pcs 4 Recoil starter Remove recoil starter from the engine 10mm box wrench M6xX12mm bolt 4 5 Aircleaner 1 Remove air cleaner cover and element cover and M6 wing bolt 1pce engine shroud 2 Remove fuel pipe from the fuel tank with fuel engine shroud tank 3 Remove engine s
35. r remedying the above disassemble the engine and check further as follows a Valve stuck open due to carbon or gum on the valve stem b If the piston rings are stuck on the piston remove the piston and connecting rod from the engine Clean or replace the parts 51 10 1 3 IGNITION SYSTEM Check the followings for lack of spark 1 Leads of the ignition coil or spark plug 2 Ignition coil damaged and shorted 3 Spark plug cable wet or soaked with oil 4 Spark plug dirty or wet 5 Spark plug electrode gap incorrect 6 Spark plug electrodes are connected or bridged 7 Incorrect spark timing 10 2 ENGINE MISFIRES 1 Incorrect spark plug electrode gap Adjust it to anywhere between 0 7 and 0 8mm 2 Ignition cable worn and leaking 3 Sparks weak 4 Ignition wire connections loose 5 Water in gasoline 6 Insufficient compression 10 3 ENGINE STOPS 1 Fuel tank empty Water dirt gum etc in gasoline 2 Vapor lock i e gasoline evaporating in the fuel lines due to overheat around the engine 3 Vapor lock in the fuel lines or carburetor due to the use of too volatile winter gas in the hot season 4 Air vent hole in the fuel tank cap plugged 5 Bearing parts seized due to lack of oil 6 Magneto or ignition coil faulty C 10 4 ENGINE OVERHEATS 1 Crankcase oil level low Add oil immediately 2 Spark timing incorrect 3 Low grade gasoline is used or engine is overl
36. rly adjusted 1 Install throttle lever control linkage on gov ernor lever and choke shaft control rod in choke lever 2 Hook spring from control lever hole A to the hole B in governor lever as shown in Fig 5 44 Install bracket assembly on crankcase 3 Install governor lever on governor shaft but do SPEED CONTROL not tighten clamp screw LEVER 4 Turn governor lever clockwise until throttle GOVERNOR valve in carburetor is opened fully Hold lever in this position See Fig 5 45 Fig 5 44 NOTE Check that governor lever clamp screw is loose so governor shaft can be turned independently of lever 5 Insert a screwdriver in slot at end of governor shaft Turn clockwise as far as shaft can be turned Tighten governor lever clamp screw Fig 5 45 237 5 4 21 MUFFLER AND MUFFLER COVER 1 Install muffler and muffler gasket 8 X 70 mm bolt and washer assy gt gt gt 2 8 X 16 mm bolt and washer assy gt 1 22 5 26 5 Nem 230 270 kgecm 16 6 19 5 ftelb 2 Install muffler cover to the muffler 5 X 10 mm Tapping screw 3 pcs 5 4 22 FUEL TANK if applicable 1 Install fuel tank bracket M6 X 12 mm bolt 2pcs 2 Install fuel tank X 12 mm bolt 2 3 Install side guard X 12 mm bolt 2pcs 4 Install cover stop switch 5 4 23 RECOIL STARTER AND ENGINE SHROUD 1 Install recoil starter and engine shroud M6 X 8 mm
37. t cam juts out from the exhaust cam The exhaust tappet rides over the crescent cam opening the exhaust valve to release compression TAPPET FLYWEIGHT 5 RELEASE LEVER CRESCENT CAM EXHAUST CAM CAMSHAFT Fig 7 1 When the crank speed reaches a certain revolution flyweight of release lever moves outward the centrifugal force turning the release lever to retract below the crescent cam Thus the exhaust valve closes allowing a sufficient compression for the engine to start up FLYWEIGHT TAPPET RELEASE LEVER CRESCENT CAM EXHAUST CAM EXHAUST CAM CAMSHAFT Fig 2 43 8 CARBURETOR 8 1 OPERATION AND CONSTRUCTION See Fig 7 2 and 81 8 1 1 FLOAT SYSTEM The float chamber is located just below the carbu retor body and with a float and a needle valve maintains a constant fuel level during engine opera tion The fuel flows from the fuel tank into the float chamber through needle valve When the fuel rises to a specific level the float rises and when its buoyancy and fuel pressure are balanced the needle valve closes to shut off the fuel thereby keeping the fuel at the predetermined level Fig 8 1 PILOT OUTLET PILOT JET MAIN NOZZLE MAIN JET Fig 8 2 add O 8 1 2 PILOT SYSTEM The pilot system feeds the fuel to the engine during idling and low speed operation The fuel is fed through the main jet to the pilot jet where it is
38. the piston reaches compression top is assembled on the camshaft for easy starting See Fig 4 13 For details refer to page 41 section 7 AUTOMATIC DECOMPRESSION SYSTEM RETURN SPRING Fig 4 13 F e 4 15 SECTIONAL VIEW OF ENGINE RECOIL STARTER BLOWER HOUSING STARTING PULLEY FLYWHEEL COOLING FAN IGNITION COIL i LIE INTAKE BER EXHAUST VALVES ae VIA ath 0 LI E 0 OIL FILLER CYLINDER HEAD PISTON PISTON PIN PISTON RING MAIN BEARING COVER CRANKSHAFT FUEL TANK Classic Steel Not available on the PUSH ROD AIR CLEANER TAPPET CAMSHAFT Pro Poly version CARBURETOR ROCKER ARM SPARK PLUG CAP CRANKCASE SPARK PLUG MUFFLER CONNECTING ROD 5 DISASSEMBLY AND REASSEMBLY 5 1 PREPARATIONS AND SUGGESTIONS 1 When disassembling the engine remember the locations of the individual parts so that they can be reassembled correctly If you are uncertain of identifying some parts it is suggested that tags be attached to them 2 Have boxes ready to keep disassembled parts by group 3 To prevent missing and misplacing temporarily assemble each group of disassembled parts 4 Carefully handle disassembled parts and clean them with oil if necessary 5 Use the correct tools in the correct way 5 2 SPECIAL TOOLS Flywheel puller For pulling off the flywheel
39. tion E SESS UTR ETT TI 6 4 11 Ignition System m Kg esos gue 7 4 12 Carburetor e 7 4 13 Air Cleaner 7 4 14 Decompression System e 8 4 15 Sectional View of Engine mme 9 5 DISASSEMBLY AND REASSEMBLY e HH eem 11 5 1 Preparations and Suggestions I 44 5 2 SpecialTools M seen 11 5 3 Disassembly Procedures He 12 5 4 Reassembly Procedures ee Henne 27 5 5 Break in Operation Henne 40 6 41 6 1 Flywheel Magneto HH nemen nennen 41 6 2 Basic Theoty e eee eRe ere eer eee 41 6 3 Wiring Diagramme 42 7 AUTOMATIC DECOMPRESSION SYSTEM 43 8 CARBURETOR eer a etras xen e no 11 44 8 1 Operation and Construction 44 8 2 Disassembly and Reassembly Hee 45 9 STARTING SYSTEM hh HH eee hh ee enhn 47 9 1 Recoil Starter ee cease je amas Oe e v e TN ES I MR VIN 47 Section Title Page 10 TROUBLESHOOTING Hehe mene 51 10 1 Starting Difficulties nnne 51 10 2 Engine Misfires HMM 52 10 3 Engine Stops HH HH 52 10 4 Engine Overheats eee 52 10 5 Engine Knocks
40. tor 4 Inferior grade gasoline or poor quality gasoline is not vaporized enough to produce the correct fuel air mixture 5 The carburetor needle valve is held open by dirt or gum This trouble can be detected as the fuel flows out of the carburetor when the engine is idling Overflow I This trouble may be remedied depending on cases by lightly tapping the float chamber with the grip of a screwdriver or the like 6 If the carburetor overflows excessive fuel runs into the cylinder when starting the engine making the fuel air mixture too rich to burn If this happens remove the spark plug and turn the starting pulley a few turns in order to let the rich fuel air mixture out of the spark plug hole into the atmosphere Keep the carburetor choke open during this operation Dry the spark plug well screw it into place and try to start again 10 1 2 COMPRESSION SYSTEM If starting difficulties and loss of power are not due to the fuel system or ignition system the following must be checked for possible lack of compression 1 Engine inside is completely dried up because of a long period of storage 2 Loose or broken spark plug This causes a hissing noise made by mixture gas running out of cylinder in compression stroke during cranking 3 Damaged head gasket or loose cylinder head A similar hissing noise is produced during compres sion stroke 4 Incorrect valve clearance If the correct compression is not obtained even afte
41. uch troubles as starting up failure due to dirty burnt or corroded point surface The electronic automatic advancing ensures extremely easy starts and stable high performance at operating speed by advancing the ignition timing to the most suitable point 6 2 BASIC THEORY To ensure the easy startability of the engine the step advancing ignition timing system is incorporated the ignition coil This system enables the engine to have basically two different ignition timings according to the engine speed Following are the explanation how the system works 1 At lower speed of the engine Rotation of the flywheel induces current L as this current flows through the base terminal of the power transistor it is activated and the current 12 starts flowing As the engine reaches the ignition timing the ignition timing control circuit for the lower engine speed is activated and lets the current L flow through the base terminal of the power transistor This generates the collector current L which will bypass the current I and abruptly shut off the current I because the power transistor is turned off This sudden current change generates a big voltage on the secondary side of the ignition coil and which sparks the spark plug 2 At the higher engine speed i Rotation of the flywheel generates the current L as this current flows through the base terminal of the power transistor it is activated and the current L starts flowing As the engine rea
42. your nearest 6 Overhaul engine Robin dearer 13 6 EVERY 1000 HOURS YEARLY MAINTENANCE 2 Disassemble and clean carburetor MAINTENANCE REMARKS REFER 1 Replace f el lines once a year Avoid hazards caused by fuel leakage 13 7 ENGINE STORAGE 1 Perform the above 13 1 and 13 2 maintenance jobs 2 Drain fuel from the fuel tank and carburetor float chamber 3 To prevent rust in the cylinder bore apply oil through the spark plug hole and turn the crankshaft several turns by hand Reinstall the plug 4 Turn the starting pulley by hand and leave it where the resistance is the heaviest 5 Clean outside of the engine with oiled cloth 6 Put a plastic cover or the like over the engine and store the engine in dry place 63 Industrial Engines Robin America Inc 940 lively Blvd Wood Dale IL 60191 Tel 708 350 8200 Fax 708 350 8212
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