Subaru Robin Power Products 27 Automobile Parts User Manual
Contents
1. Cylinder head bolts 22 5 26 5 230 270 16 6 19 5 EH12 2 EH17 2 EH12 2 EH17 2 EH12 2 EH17 2 connecting roe bolts 16 6 19 6 90 115 170 200 655 83 122 144 Flywheel nut 58 8 63 7 600 650 43 47 Main bearing cover bolts 7 8 9 8 80 100 5 7 7 2 Spark plug Retightening 22 6 26 5 230 270 16 6 19 5 EH25 2 type TIGHTENING TORQUE DESCRIPTION Cylinder head bolts 33 3 41 2 340 420 Connecting rod cap bolts 21 3 26 9 225 275 16 3 19 8 Flywheel nut 58 8 63 7 600 650 Main bearing cover bolts 170 190 12 3 13 7 New spark plug 11 8 14 7 120 150 8 7 10 9 Spark plug Retightening 22 6 26 5 230 270 16 6 19 5 12 3 OIL GRADE CHART between oil viscosity Comparison between oil viscosity andtemparature temparature 20 10 0 10 20 30 40 2 4 14 32 50 68 86 104 F Use oil classified as SE or higher Multi grade oil tends to increase its consumption at high ambient temperature 13 MAINTENANCE AND STORAGE The following maintenance jobs apply when the engine is operated correctly under normal conditions The indicated maintenance intervals are by means guarantees for 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 1 Clean away dust2. waw 11 4 11 Lubrication EIE 11 4 12 Ignition System DIPL 11 4 1 3 Carburetor e e 12 4 1 4 Air Cleaner CREER TAH Hee HEH AEE EEE ETES EEE EEE EEE EEE EE EEE EEE EEE 12 4 15 Balancer Option for EH25 2 slaga alaa aa e sn dore ma den ed des 12 4 16 Decompression System AS et desde presses re Suyupa ciate Mate de 13 4 1 7 Sectional View of Engine K a 4 14 5 DISASSEMBLY AND REASSEMBLY 16 5 1 Cautions mh HH hh m hne 16 5 2 Special Tools 444 44 16 5 3 Disassembly Procedures DIDI 17 5 4 Reassembly Procedures 32 5 5 Break In Operation EXPO 43 6 IGNITION SYSTEM e 43 6 1 Type of Ignition System oaeaaaa 43 6 2 Basic Theory s 43 6 3 Wiring Diagram
3. 45 7 AUTOMATIC DECOMPRESSION SYSTEM HMM 46 8 CARBURETOR Metti sheets saosestsssosososevseosevooesseceeseosvosves 47 8 1 Operation And Construction 47 8 2 Disassembly And Reassembly e HH 48 Section Title Page 9 10 11 12 13 STARTING SYSTEM vv n n t n mtem Immnt 50 9 1 Recoil Starter v Mm 50 TROUBLESHOOTING MH 5A 10 1 Starting Difficulties e o 54 10 2 Engine Misfires 4 4 ry 10 3 Engine Stops 444444444 eee rene seen 55 10 4 Overheats ones sense ses en 55 10 5 Engine Knocks waeoe 56 10 6 Engine Backfires Through Carburetor HM 56 INSTALLATION ee MH 57 1 1 1 Installing IPTE 57 1 1 2 Ventilation 4 ee ee anana aana anana 57 1 1 3 Exhaust Gas Discharge eee eee eee ee ee eee ee eee ee ee 57 11 4 Power Transmission To Driven Machines m 57 SERVICE DATA e HH Hh hehehe 58 12 1 Clearance Data And Limits 58 12 2 Torque Sp
4. gt 1 1 0 2000 3000 4000 1000 1500 2000 REVOLUTION gt r p m EH17D B forBtype N m kgf m em aa m L ELLE t 20 1 000 MAXIMUM TORQUE kW 9 18 id RD o 5 4 5 82 2000 3000 4000 1000 1500 2000 REVOLUTION r p m E 25D B forB type kgf m 7 3 4 2 tr O 1 5 3 0 4 2 8 2000 3000 4000 1000 1500 2000 REVOLUTION r p m 3 FEATURES 1 The overhead valve design offers compactness light weight and ideal combustion characteristics resulting in more power from less fuel and prolonged engine life An optimum lubrication and better tilted operation thanks to upright cylinder design A crossflow arrangement of intake and exhaust ports ensures stable performance under high ambi nt temperature The automatic decompressiom system lightens the recoil pull force by 40 comparing to the conventional SV engines An easy operation thanks to integrated engine control system Improved throttle mechanism is adopted for easy starting Combustion and mechanical noises have been analyzed acoustically and improved for better tonal quality and lower engine noise Optimally designed reciprocating parts reduce the vibration level of the engine EH25 2 engine equips single through balancer shaft as an option 4 GEN
5. 75 269 reboring 2 9626 2 9633 2nd 75 500 75 519 reboring 2 9724 2 9732 LESS THAN 0 015 0 0006 74 98 75 00 74 89 2 9520 2 9528 2 9484 1510 5 75 23 75 25 75 14 2 9618 2 9626 2 9583 n os 75 48 75 50 75 39 2 9717 2 9724 2 9681 Roundiness after reboring Cylindricity after reboring PISTON Piston size At skirt in thrust direction EH25 2 4 5mm 0 18 Pistn pin hole Piston pin outside dia Cle ance between piston and cylinder at skirt area Pis n ring end gap 0 030 0 075 0 0012 0 0030 0 030 0 075 0 0012 0 0030 0 020 0 075 0 0008 0 0030 12 991 13 002 0 5115 0 5119 12 992 13 000 0 5115 0 5118 0 015 0 074 0 0006 0 0029 0 2 0 4 0 008 0 016 0 2 0 4 0 008 0 016 12 960 0 5102 0 25 0 010 1 5 0 0591 1 5 0 0591 0 035 0 080 0 0014 0 0031 0 025 0 070 0 0010 0 0028 0 010 0 065 0 0004 0 0026 15 991 16 002 0 6296 0 6300 15 992 16 000 0 6296 0 6299 0 015 0 074 0 0006 0 0029 0 2 0 4 0 008 0 016 0 05 0 25 0 0002 0 010 Uni mm 1 0 6 035 6313 15 960 0 6284 0 25 0 010 1 5 0 0091 1 5 0 0591 Unit mm in 0 050 0 090 0 0020 0 0035 0 030 0 070 0 0012 0 0028 0 010 0 065 0
6. All the rotating and sliding parts are splash lubricated by the oil scraper on the connecting rod 4 12 IGNITION SYSTEM The ignition system is a transistor controlled mag neto ignition system which cosists of a flywheel and an ignition coil with a built in transistor This system has an ignition timing advance for easy starting 11 IS 5 j NS 724 GOVERNOR GEAR Fig 4 9 OIL SCRAPER Fig 4 10 IGNITION COIL FLYWHEEL Fig 4 11 4 13 CARBURETOR The engines equipped with a horizontal draft carburetor that has a float controlled fuel system and a fixed main jet The carburetors are calibrated carefully for easy starting good acceleration low fuel consumption and sufficient output 4 14 AIR CLEANER The air cleaner is a single urethane foam element system As an option heavy duty type with a double element type is available CLEANER COVER CLEANER CASE ELEMENT CLEANER BASE ELEMENT Single element type Double element type Fig 4 13 1 Fig 4 13 2 4 15 BALANCER Option for EH25 2 Unbalanced inertia force is balanced by the balancer which rotates at the same speed with the crankshaft y BALANCER to effectively reduce vibration 5 Fig 4 14 4 16 DECOMPRESSION SYSTEM An automatic decompression mechanism which opens exhaust valve before the piston reaches com pression top is assembled on the camshaft for easy starti
7. Following are the explanation using type D engine as sample how the system works The components of the systems are different for the type D and type B engines however the principle of the function is same At the end of the compression process the release lever lifts up the tappet which in turns opens up the exhaust valve slightly to release the compression The release lever has a flyweight on its end and another end of the lever is a crescent cam When the engine is cranked the crescent cam projects the camshaft cam profile and lifts up the tappet because the gravity force on the weight is larger than the centrifugal force on the weight TAPPET FLYWEIGHT RELEASE LEVER CRESCENT CAM EXHAUST CAM EXHAUST CAM CAMSHAFT Fig 7 17 When the crank speed reaches up to a certain revolution the crescent cam is retracted into the camshaft cam profile because the centrifugal force applied onto the flyweight becomes larger than the gravity force and the weight and is shifted to the position shown in the illustration FLYWEIGHT TAPPET EXHAUST CAM CAMSHAFT RELEASE LEVER CRESCENT CAM EXHAUST CAM Fig 7 2 8 CARBURETOR 8 1 OPERATION AND CONSTRUCTION 8 1 1 FLOAT SYSTEM The float chamber is located below the carburetor body and with a float and a needle valve maintains constant fuel level during the engine operation The fuel flows from the fuel tank into
8. 0004 0 0026 Piston pin hole Piston outside dia Clearance between piston and cylinder at skirt area 17 991 18 002 0 7083 0 7087 17 992 18 000 0 7084 0 7087 0 025 0 064 0 0001 0 0025 Piston ring end gap 0 1 0 3 0 004 0 012 1 5 0 0591 0 1 0 3 1 5 0 004 0 012 0 0591 Unit mm a eee sp E 2 26 000 26 013 26 1 1 0236 1 0241 1 0276 0 020 0 046 0 2 0 0008 0 0018 0 008 13 010 13 021 13 08 0 5122 0 5126 0 5150 0 010 0 029 0 12 0 0004 0 0011 0 0047 01 07 1 0 0 004 0 028 0 040 25 967 25 980 25 85 1 0223 1 0228 1 0177 CONNECTING ROD Big end inside dia Clearance between big end and crankpin Small end inside dia Clearance between small end and piston pin 9 Big end side clearance CRANKSHAFT Crankpin outside dia Journal dia D1 D2 24 988 24 997 0 9839 0 9841 Unit mm in 17 2 Sm mt 30 1 1 1850 0 2 0 008 16 08 06331 0 12 0 0047 1 0 0 040 29 85 1 1752 CONNECTING ROD 9 Big end inside dia 30 000 30 016 1 1811 1 1817 Clearance between big end and crankpin 0 020 0 049 0 0008 0 0019 Small end inside dia 16 010 16 021 0 6303 0 6308 Clearance between smal
9. 2 Apply oil to the rocker arms and assemble them to the cylinder head using pivot bolt and guide plate 5 4 10 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 12 o clock 10 o clock EH12 2B 17 2B 25 2D EH12 2D 17 2D 25 2B Fig 5 37 2 Loosen the nut under the rocker arm and turn the bolt pivot to adjust the clearance between the rocker arm and the valve stem end Tighten the nut under the rocker arm 0 08 0 12 mm 0 0031 0 0047 in NOTE Check and adjust valve ciearance while engine is cold Check operation of valves by turning crankshaft Recheck valve clearance Fig 5 38 3 Install rocker cover and gasket Rocker cover X 12 mm bolt 4 pcs 5 4 11 SPARK PLUG Install spark plug to the cylinder head Spark plug EH12 2 NGK B6ES EH17 2 25 2 NGK B6HS Tightening torque New spark plug Retightening 11 8 14 7 Nem 22 6 26 5 Nem 120 150 kgecm 230 270 8 7 10 9 16 6 19 5 ftelb 5 4 12 FLYWHEEL MAGNETO 1 Install the charge coil to the crankcase Option NOTE Be careful not to pinch coil wire between charge coil and crankcase 2 Put the woodruff key in the key way of crank shaft Wipe off oil and degrease thoroughly from the tapered portion of the crankshaft and the flywheel cente
10. 3m long pipe inside diameter 30mm Less than 5m long pipe inside diameter 33mm 11 4 POWER TRANSMISSION TO DRIVEN MACHINES 11 4 1 BELT DRIVE Take the following notes into consideration V belts are preferable to flat belts The driving shaft of the engine must be parallel to the driven shaft of the machine The driving pulley of the engine must be in line with the driven pulley of the machine Install the engine pulley as close to the engine as possible If possible span the belt horizontally Disengage the load when starting the engine If no clutch is used use a belt tension pulley or the like 11 4 2 FLEXIBLE COUPLING When using a flexible coupling runout and misalignment between the driven shaft and engine shaft must be minimized Runout and misalignment tolerance are specified by the coupling manufacturer 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 measurement exceeds beyond the Limit the part needs to be replaced and or repaired 12 1 CLEARANCE DATA AND LIMITS Unit mm in EH12 2 17 2 25 2 STD LESS THAN 0 05 0 002 0 004 0 7 1 0 2 0 0 028 0 039 0 079 5 65 0 2224 6 15 0 2421 CYLINDER HEAD Flatness Valve seat contact width Valve guide inside dia 5 50
11. Dry Weight 24 0 kg 52 9 lb 28 0 kg 61 7 lb 23 0 kg 50 7 lb 27 0 kg 59 5 lb Length 333 mm 13 111 333mm 13 11 in 332mm 13 07 in 332 13 07 in Dimensions Width 380 mm 14 96in 380 14 96in 380 mm 14 96 in 380 mm 14 96in Height 440mm 17 32in 440 mm 17 32in 440 17 32in 440 mm 17 32in 2 PERFORMANCE 2 1 MAXIMUM The maximum output is the output of an engine with its throttle valve fully opened under the condition that all the moving parts are properly worn in after the initial break in period A new engine may not produce full maximum output while its moving parts are still not broken in 2 2 CONTINUOUS RATED OUTPUT The continuous rated output is the output of an engine at optimum governed speed which is most favorable from the view point of engine s life and fuel consumption When the engine is installed on a certain equipment it is recommended that the continuous output required from the engine be kept below this continuous rated output 2 3 MAXIMUM TORQUE The maximum torque is the torque at the output shaft when the engine is producing maximum output at certain revolution 2 4 PERFORMANCE CURVES EH12D B for type kgf m LL T TL T TITI L 88 70 8 01 6 DP 7 14 0 7 1 4 up KW MAXIMUM TORQUE EAS ar E 6 12 0 6 1 2 i ul 2 G x 2 RECOMMENDED HORSEPOWER
12. Refer to the illustration below See Fig 5 9 14mm nut Ipc EH12 2 17 2 18mm nut Ipc EH25 2 19mm EH12 2 17 2 24mm EH25 2 socket wrench to KEY SWITCH Se M6 BOLT and WASHER 2pcs STARTER PULLEY C S2 14 NUT 1 pc EH12 2 17 2 M18 NUT 1 pc EH25 2 24 1 Remove flywheel from crankshaft 2 Remove key from crankshaft See Fig 5 12 Use flywheel puller as illustrated below See Fig 5 11 Flywheel puller Charge coil Option 1 Remove charge coil M6x 25mm Screw 2pcs STEP 1 7 RING GEAR to DIODE RECTIFIER M6 SCREW 2 pcs STEP 18 CHARGE COIL 2 ES LAIN lt Fig 5 13 Fig 5 12 see 19 Rocker cover 1 Remove rocker cover from cylinder head 6 12mm flange bolt 4pcs socket wrench 2 Remove gasket rocker cover 20 Cylinder head 1 Remove cylinder head from crankcase 12mm 14 M3X65mm flange bolt gt gt 4pcs socket wrench EH12 2 17 2 MIOX75mm flange bolt 4pcs EH25 2 lt 2 Detach cylinder head gasket from cylinder head 3 Remove push rods M6 FLANGE BOLT 4 pcs ROCKER COVER M8 FLANGE BOLT 4 pcs EH12 2 17 2 M10 FLANGE BOLT 4 pcs EH25 2 GASKET 1 CYLINDER HEAD GASKET m
13. and chaff from engine Governor linkage is especially sensitive to dust 2 Check fuel leakage from fuel system If any retighten fasteners or replace necessary parts 3 Inspect for loose hardwares and retighten if Loose bolts and nuts may come off and result in breakage of other necessary parts 4 13 2 INITIAL 20 HRS MAINTENANCE 1 Change crankcase oil To remove sludge from run in operation 13 3 EVERY 50 HRS 10 DAYS MAINTENANCE 1 Change crankcase oil Contaminated oil quickens wear 3 Check and clean spark plug If dirty wash in gasoline or polish with emery paper 13 4 EVERY 100 200 HRS MONTHLY MAINTENANCE 2 Inspect cooling system and remove dirt and Remove blower housing and clean up between fins and housing chaff 13 5 EVERY 500 600 HRS MAINTENANCE 1 Remove carbon from cylinder head Carbon deposits in combustion chamber causes lack of power 13 6 EVERY 1000 HRS YEARLY MAINTENANCE 1 Overhaul engine Clean and correct parts Replace piston rings and other necessary parts 2 Replace fuel 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
14. engine more easily 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 8 2 1 THROTTLE SYSTEM 1 Remove the philips screw 1 and throttle valve 2 and pull out the throttle shaft 3 2 The spring 4 can be taken out by removing the throttle stop screw 5 Be careful not to damage the throttle valve rim 8 2 2 CHOKE SYSTEM 1 Remove the philips screw 6 and choke valve 7 and pull out the choke shaft 8 2 When reassembling the choke shaft make sure that the cutout in the choke valve faces the main air jet Meanwhile when reassembling set the rings 9 and 10 at the right position 8 2 3 PILOT SYSTEM 1 Remove the pilot jet 11 using proper tools to avoid damage to it 2 Reassembly Tighten the pilot jet securely Otherwise the fuel may leak causing engine malfunction Fig 8 3 8 2 4 MAIN SYSTEM 1 Remove the bolt 12 and take out float chamber body 13 2 From the body 14 remove the main nozzle 15 and then remove the main jet 16 and guide holder 17 from the main nozzle 15 3 Reassembly a Fasten the main jet securely to the body Otherwise
15. 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 iterfering the fuel flow to the carburetor 4 Inferior grade gasoline or poor quality gasoline 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 This trouble may be remedied 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 choke valve 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 difficultes and loss of power are not due to the fuel system or ignition system the followings 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
16. 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 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 overloaded 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 gaoline detonates due to heavy load at low speed 10 5 ENGINE 5 1 Poor quality gasoline 2 Engine operating under heavy load at low speed 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 Cuases of engine overheat 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 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 Review the following instr
17. 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 compression stroke 4 Incorrect Valve clearance If the correct compression is not obtained even after remedying the above disassemble the engine and check further as follows 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 10 1 3 IGNITION SYSTEM Check the followings for lack of sparks 1 Wires of the ignition coil spark plug or contact breaker disconnected 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 ENGINGE MISFIRES 1 Incorrect spark plug electrodge gap Adjust it to anywhere between 0 6 and 0 7mm 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
18. the reel Fig 9 4 3 Hold the reel so that the shaft hook part and the inner end of the spring are hooked to gether Drop the reel gently from above into the case 4 Move the reel slightly counter clockwise and make sure the spring is hooked SHAFT HOOK PARTS Fig 9 3 THE POSITION THE END TOUCHES THE RIB OF THE BEARING Fig 9 4 2 Setting the attachments 1 Set the latchet into the reel Fig 9 5 T THE LATCHET IS KEPT AT CLOSE POSITION Fig 9 5 2 Holding the latchet set the latchet guide sub assembly Fig 9 6 SET SCREW RATCHET Dan FRICTION SPRING LATCHET GUIDE SUB ASSEMBLY Fig 9 6 3 Tightening the set screw 1 Push the latchet guide lightly by hand so that the latchet guide won t move and tighten the set screw 4 Storing the spring power 1 Hold the case tight and using both hands wind up the reel counter clockwise 6 times 2 Set the ree to keep the position whereby the rope hole of the reel and the rope guide make a direct line Fig 9 7 Fig 9 7 WARNING The spring power is at its most when the reel is being wound Therefore do not abruptly put off your hand nor loosen the pressure of your finger unintentionally 5 Setting the rope 2 persons required 1 Set the end of the rope through the rope guide and the rope hole of the reel and pull the end about 20 cm out of the reel Fig 9 7 2 Fasten the end of the rope AB
19. to be loosened and Governor shaft spring M6 X30mm bolt and washer 3 Detach governor lever governor rod and rod spring from carburetor Speed control 1 Remove stop plate friction plate and 10mm lever speed control lever socket wrench M6 X 14mm flange bolt Ipc 1 Remove intake pipe from cylinder head Be careful not to lose 10mm 12mm M6 flange nut 2pcs EH12 2 17 2 insulator and gasket socket wrench M6 X25mm flange bolt Ipc EH12 2 17 2 M8 28mm bolt and washer 3pcs 25 2 M6 FRANGE BOLT 1 pc 8 Bus STEP 13 STOP PLATE M6 FLANGE NUT 2 pcs EH12 2 17 2 GASKET INSULATOR M6 FLANGE BOLT 1 pe EH12 2 17 2 FRICTION PLATE p c and WASHER 3 pcs EH25 2 A SPEED CONTROL LEVER i p x Ze INSULATOR 2 E GOVERNOR SPRING N lt STEP 11 ROD SPRING CARBURETOR GOVERNOR ROD GOVERNOR LEVER AE STEP 10 M6 BOLT and WASHER 1 pc d Fig 5 8 Step Partto remove Procedures Remarks Tool 14 Ignition coil 1 Disconnect ignition plug cap and remove 10mm ignition coil from crankcase socket wrench Starter pulley M6X25mm bolt and washer 2pcs js IGNITION PLUG CAP 1 Remove starter pulley from flywheel Do not place bar or screw Place socket wrench on flywheel fastening driver in flywheel fin to nut and strike tip of the lever with loosen flywheel nut hammer
20. 0 5 518 0 2165 0 2172 6 035 6 053 0 2376 0 2383 Unit mm CYLINDER Inside dia To be rebored when the difference between max and min of diameter reached to 0 1 0 004 To be rebored when the difference between max and min of diameter reached to 0 1 0 004 60 000 60 019 2 3622 2 3630 67 000 67 019 2 6378 2 6385 60 250 60 269 2 3720 2 3728 67 250 67 269 2 6476 2 6484 151 reboring 2nd 60 500 60 519 reboring 2 3819 2 3826 67 500 67 519 2 6575 2 6582 Roundiness after reboring LESS THAN 0 01 Cylindricity after reboring LESS THAN LESS THAN 0 015 0 015 0 0006 0 0006 PISTON Piston size At skirt in thrust direction STD 59 96 59 98 59 87 66 98 67 00 66 89 2 3606 2 3614 2 3571 2 6370 2 6378 2 6335 1st o s 60 21 60 23 60 12 67 23 67 25 67 14 2 3705 2 3713 2 3669 2 6469 2 6476 2 6433 60 37 EH12 2 4 5mm 0 18 EH17 2 4 5mm 0 18 60 46 60 48 2 3803 2 3811 67 48 67 50 2 6567 2 6575 67 39 2 6531 Unit in CYLINDER inside dia To be rebored when the difference between max and min of diameter reached to 0 1 0 004 75 000 75 019 2 9528 2 9535 ist 75 250
21. 17 18 5 Nem 170 190 12 5 13 5 ftelb 5 4 8 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 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 valve springs spring retainers and collet valves 4 Valve guides should be replaced when the valve stem clearance exceeds specifications See SERVICE DATA Draw the valve guides out and press the new guides in Refer to SERVICE DATA for clearance specifications After replacing the valves and guides lap valves in place until a uniform ring shows around the face of the valve Clean valves and wash cylinder head thoroughly 5 Install cylinder head to cylinder with new head gasket Tighten four flange bolts evenly in three steps by the following tightening torque Cylinder head M8 X 65 mm flange bolt 4 pes EH12 2 17 2 M10 X 75 mm flange bolt 4 pcs 25 2 Tightening torque EH12 2 17 2 3 6 ft lb 17 30 ft Ib Tightening torque EH25 2 ist step final step 9 8 Nem 33 3 41 2 Nem 100 200 kg cm 340 420 kg cm 7 2 ftelb 14 5 ft lb 24 6 30 4 ftelb 5 4 9 ROCKER ARMS AND PUSH RODS 1 Insert push rods into crankcase Put push rod tip in the hollow of tappet top
22. 2 2 17 2 8 X 16mm flange bolt 1 pc EH25 2 Install the muffler cover and exhaust pipe cover M6 X 10mm flange bolt 5 pcs 5 4 20 BLOWER HOUSING RECOIL Install the blower housing and the recoil Insert the high tension cord from the ignition coil into the notch of the blower housing so tbat not to pintch the cord 5 4 21 FUEL TANK Install the fuel tank Connect the fuel strainer and the fuel inlet on carburetor with the fuel hose M6 X 14mm bolt and washer 4 pcs EH12 2 17 2 8 X 20mm bolt and washer 4 pcs EH25 2 End of the reassembly 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 throughly 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 see cem munem 3600 rpm 3600 rpm 6 IGNITION SYSTEM 6 1 TYPE OF IGNITION SYSTEM EH12 2 employs the U T C I Universal type Transistor Controlled Ignition pointless ignition system EH17 2 and EH25 2 have the T I C Transistor Igniter Circuit pointless ignition system As optional parts these 1gnition system may be implemented w
23. ERAL DESCRIPTION OF ENGINE COMPONENTS 4 1 CYLINDER AND CRANKCASE The cylinder and crankcase is single piece aluminum diecasting The cylinder liner made of special cast iron is molded into the aluminum casting The crankcase has a mounting surface the output shaft side where the main bearing cover is attached 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 the inside of the engine The pilots and bosses are machined on the cover for direct mounting of the engine onto such machines as generators and pumps Oil gauge fillers are on both sides of the cover for easy maintenance OIL GAUGE 4 3 CRANKSHAFT The crankshaft is forged carbon steel and the crank pin is induction hardened The output end of the shaft has crankshaft gear and balancer gear for EH25 2 which are pressed into position Fig 4 3 4 4 CONNECTING ROD AND PISTON The connecting rod is an aluminum alloy diecasting and its large and small ends function as bearings The piston is an aluminum alloy casting and carries two compression rings and one oil ring Fig 4 4 4 5 PISTON RINGS The piston rings are made of special cast iron The profile of the top ring is barrel face and the second ring has a tapered face The oil ring consists of a cutter ring and a coil T P RING expander for better sealin
24. Main bearing 1 Remove main bearing cover fastening Be careful not to damage 10mm 12mm cover bolts oil seal socket wrench M6x30mm bolt and washer 8pcs EH12 2 17 2 M8X30mm bolt and washer 8pcs EH25 2 2 Remove main bearing cover using plastic hammer See Fig 5 15 Fig 5 15 GASKET MAIN BEARING COVER M6 BOLT and WASHER 8 pes EH12 2 17 2 M8 BOLT and WASHER 8 pcs EH25 2 Fig 5 16 CS ms Cam shaft 1 Remove cam shaft from crankscase To prevent tappets from Balancer shaft 2 Remove balancer shaft getting damaged put the Option for Option for EH25 2 crankcase upside down 25 2 See Fig 5 17 1 Remove tappets from crankcase Put a tag on tappets to identify intake and exhaust CAMSHAFT BALANCER SHAFT OPTION for EH25 2 CAMSHAFT D type Fig 5 18 10mm socket wrench 1 Remove connecting rod bolt after scraping off carbon from cylinder and piston M6X34mm flange bolt 2pcs 12 2 M7X37mm flange bolt 2pcs EH17 2 MB x 46mm flange bolt 2pcs EH25 2 2 Remove connecting rod cap 3 Remove connecting rod from upper side of crankcase after rotating crankshaft so that piston comes up to top dead center Connecting rod and Piston Piston and Piston rings 1 Remove clips and piston pin Do not damage the 2 Remove piston from connectin
25. OUT 20mm Fig 9 8 3 Put the rope into the reel whereby make sure that the rope will not float up Fig 9 9 4 Hold the rope firmly with one hand at the position about 50 cm from the rope guide and keep the rope slightly pulled so that the rope will not be wound in 5 Put the hand off the reel gently and put the rope back slowly obeying the winding power of the spring until the knob reaches the rope Assembly is complete i Fig 9 9 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 10 TROUBLESHOOTING The following three conditionts must be fulfilled for satisfactory engine start 1 The 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
26. Robin Industrial Engines SERVICE MANUAL EH12 2 EH17 2 EH25 2 Engines PUB ES1154 Rev 5 99 Robin SUBARU CONTENTS Section Title Page 1 SPECIFICATIONS nono ane sms soeurs 1 2 PERFORMANCE gt eaeae 4 2 4 Maximum Output Hen 4 2 2 Continuous Rated Output eH 4 2 3 Maximum Torque mener 4 2 4 Performance Curves eeaoeos 5 3 FEATURES rene tante ao Fux A Sane entente ne 8 4 GENERAL DESCRIPTION OF ENGINE COMPONENTS 8 4 1 Cylinder And Crankcase mmm 8 4 2 Main Bearing Cover nono ns sn toss t tnn 8 4 3 Crankshaft s n 9 4 4 Connecting Rod And Piston 4 4 4 ns nm sn ns 9 4 5 Piston Rings EEE EEE EEE EEE EEE EEE EEE EEE EEE EE EEE 9 4 6 Camshaft Pel KG Ga KAG e E Wis a E E EE NE eques dis eral E E so 10 4 7 Valve Arrangement PET 10 4 8 Cylinder Head sss HH Hh heh heh 10 4 9 Governor System N A REACTOR ARE ACA RR RA EO C rere 11 4 10 Cooling System
27. Turn the speed control lever all the way toward the high speed position and make sure that the throttle valve in the carburetor is at the wide open position 5 Turn the governor shaft clockwise all the way using a screw driver and tighten the lock bolt and nut See Fig 5 43 For the generator applications there are two different governor springs existing according to the speed setting of the engine The governor springs may be distinguished by the following table The governor spring employed on the 60Hz application is same as the one from the standard specifi cations SPEED CONTROL LEVER HIGHER SPEED qe GOVERNOR SPRING EN GOVERNOR LEVER Fig 5 42 Fig 5 43 N SPRING WOUND EH12 2 EH17 2 EH25 2 CES Toni 3609 mE 3000 Bd 30001 3600 BENE 49 4949 38 1 38 5 43 1 4307 D 9460359 84 10 7 0 42 96 m 8 7 0 347 a G 5 4 17 AIR CLEANER Install the air cleaner gasket and the cleaner case and tighten them with 2 M6 flange nuts Then install the element and the cleaner cover 5 4 18 HEAD COVER Install the head cover to the cylinder head M6 X 12mm flange bolt 1 pc 5 4 19 MUFFLER MUFFLER COVER and EXHAUST PIPE COVER Install the muffler to the cylinder head M8 flange nut 2 pcs 22 5 26 5 Nem 230 270 kg cm 16 6 19 5 ftelb Then tighten the muffler bracket portion M6 X 12mm flange bolt 1 pc EH1
28. 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 e Robin SUBARU Industrial Engines Robin America Inc 940 Lively Blvd Wood Dale IL 60191 Phone 630 350 8200 Fax 630 350 8212 e mail sales robinamerica com www robinamerica com PRINTED IN THE USA Robin America Inc
29. camshaft bearing 2 Measure the height B2 From the mating surface to the camgear inner boss A2 0 3 B2 SIDE CLEARANCE mm SIDE CLEARANCE 0 2 THICKNESS OF CAMSHAFT SHIM mm A2 0 012 B2 SIDE CLEARANCE in SIDE CLEARANCE 0 008 55 OF CAMSHAFT SHIM in Following are availalbe spacer shims EH12 2 EH17 2 type T emer CAMSHAFT T 0 6 mm 0 0247 T 0 6 mm 0 0247 SPACER SHIMS T 0 8 mm 0 031 T 0 8 mm 0 0317 T 1 0 mm 0 039 T 1 0 mm 0 039 EH25 2 type BOE CRANKSHAFT For D type CRANKSHAFT For B type CAMSHAFT T 0 6 mm 0 0247 1 2 7 mm 0 1067 0 6 mm 0 024 SPACER SHIMS T 0 8 mm 0 0317 T 2 9 mm 0 114 T 0 8 mm 0 0317 T 1 0 mm 0 0397 T 3 1 mm 0 1227 1 0 mm 0 039 CRANKCASE CRANKSHAFT SPACER MAIN BEARING COVER CAMSHAFT SPACER type only GASKET BEARING COVER Fig 5 36 2 Lubricate the oil seal and bearing surfaces Add a light film of oil on the main bearing cover face to hold the gasket in place Place spacers chosen at procedure 1 on crankshaft and camshaft Use an oil seal guide when installing the main bearing cover to avoid damaging the seal Tap the cover into place with a soft hammer Main bearing cover EH12 2 17 2 M6 X 30 mm bolt and washer 8 pcs EH25 2 M8 X 30 mm bolt and washer 8 pcs Tightening torque EH12 2 17 2 Tightening torque EH25 2 8 9 5 Nem 80 100 kg cm 6 7 ftelb
30. e crank shaft as shown in the illustration CAUTION Incorrect timing of the gears will cause malfunction of the engine and may result in damage due to interference of the parts 5 4 6 TAPPET AND CAMSHAFT 1 Oil the tappets and install them in their original position Push in fully to avoid damage during the installation of the camshaft 2 Lubricate the bearing surfaces of camshaft Align the timing mark on the crankshaft gear with the timing mark on the camshaft and install the camshaft in the crankcase as shown in the illustration CAUTION Incorrect valve timing will cause engine s malfunction 5 4 7 ADJUST CRANKSHAFT AND CAMSHAFT END PLAY 1 Adjust end play to the specified values using the proper spacer The proper spacer may be determined following manner MAIN BEARING COVER Al A2 GASKET 0 3 CRANKSHAFT 1 2 CRANKCASE Fig 5 35 5 4 7 1 CRANKSHAFT END PLAY For D type and B type 1 Measure the depth A1 From the mating surface to the inner race of the ball bearing 2 Measure the height B1 From the mating surface 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 5 4 7 2 CAMSHAFT END PLAY Model B 2 1 Reduction type only 1 Measure the depth A2 From the mating surface to the inner race of the
31. e stem dia and valve guide 0 045 0 078 0 0018 0 0031 0 056 0 092 0 0022 0 0036 0 08 0 12 0 0031 0 0047 Unit mm in 30 6 30 8 30 45 1 205 1 213 1 199 24 967 24 980 24 95 0 9830 0 9835 0 9823 14 973 14 984 14 95 0 5895 0 5899 0 5886 5 975 5 990 5 85 0 2352 0 2358 0 2303 5 960 5 975 5 85 0 2346 0 2352 0 2303 0 3 0 012 0 3 0 012 CAMSHAFT Cam height Journal outside dia D type VALVE Valve stem outside dia Clearance between valve stem dia and valve guide 0 045 0 078 0 0018 0 0031 0 060 0 093 0 0024 0 0037 Valve clearance 0 08 0 12 0 0031 0 0047 Stem outside dia Guide inside dia Tappet guide clearance Unit mm in EH12 2 EH17 2 7 960 7 975 0 3134 0 3140 8 000 8 015 0 3150 0 8156 0 025 0 055 0 0010 0 0022 Unit mm in TAPPET Stem outside dia 7 960 7 975 0 3134 0 3140 Guide inside dia 8 000 8 015 0 3150 0 3156 Tappet guide clearance 0 025 0 055 0 0010 0 0022 Unit mm 12 2 17 2 25 2 VALVE SEAT ANGLE IN EX Valve cutter angle a Valve contact width b a 90 b 0 7 1 0 0 028 0 039 12 2 TORQUE SPECIFICATIONS EH12 2 17 2 type TIGHTENING TORQUE DESCRIPTION
32. ecifications 70 12 3 Oil Grade Chart HH nennt 71 MAINTENANCE AND STORAGE eee 72 13 1 Daily Maintenance ttt III 72 13 2 Initial 20 Hours Maintenance 72 13 3 Every 50 Hours 10 Days Maintenance i 72 13 4 Every 100 200 Hours Monthly Maintenance 7000000000 n n 73 13 5 Every 500 600 Hours Maintenance Ce 73 13 6 1000 Hours Yearly Maintenance 4 44 4 ona 73 13 7 Storage eee eee ee ee ee nono nero 73 1 SPECIFICATIONS DL M Air Cooled 4 Single Cylinder Horizontal Shaft Gasoline Engine Wewn ws _ Spark Plug r A B6ES and Electric Recoil and Electric Starting System Recoil Starter Recoil Starter Speed Reduction Speed Reduction 2 1 Cam Shaft Drive Governor System Centrifugal Flyweight System Air Cooled 4 Cycle Single Cylinder Horizontal P T O Shaft Gasoline Engine Output Continuous 2 6 3 5 3000 2 9 4 0 3600 KW HP rpm 4 4 6 0 4000 4 2 Max Torque Nem kgf m rpm 21 4 2 18 1300 10 7 1 09 2600 Direction of Rotation Counterclockwise As Viewd From P T O Shaft Side Cooling system Forced Air Cooling Valve Arrangeme
33. er head MB nut 2 M6 12mm flange bolt 12 2 17 2 8 16mm flange bolt 1pc EH25 2 GASKET M8 NUT 2 pcs EXHAUST PIPE COVER MUFFLER M6 FLANGE BOLT 5 pcs MUFFLER COVER Fig 5 5 20 Part to remove Procedures Remake Tool Control box 1 Disconnect wires and Electric blue 4 diode rectifier starter light blue 4 diode rectifier Option black 1 magnetic switch 2 Remove black wires from electric starter 3 Remove control box Fastened together with fuel tank 4 Loosen two bolts and remove electric 12 socket wrench starter MS bolt 9pes 7 CONTROL BOX to CHARGE COIL BLUE and LIGHT BLUE 67 A KEY SWITCH to IGNITION COIL M8 BOLT and WASHER 2pcs P d ELECTRIC STARTER Fig 5 6 21 1 Remove head cover crankcase 10mm A M6X12mm flange bok Ipc socket wrench Air cleaner 1 Remove cleaner cover and cleaner Fastened together with 10mm element carburetor socket wrench 2 Remove M6 flange nut 2pcs lt GASKET CLEANER CASE PLATE ELEMENT HEAD COVER M6 FLANGE BOLT 1 pc 10 Governor 1 Unhook governor spring from speed Bolt and washer on 10mm lever control lever governor lever only socket wrench Governor rod 2 Remove governor lever from governor needs
34. g and less oil consumption SECOND RING OIL RING Fig 4 5 4 6 CAMSHAFT The camshaft for the D type engine is made of special cast iron and camshaft gears are casted to gether in one piece Both sides of the shaft fit into the plane bearings on the crankcase and main bearing cover The camshaft for the B type engine is made of forged carbon steel and also functions as PTO shaft The cam gear is press fitted on the shaft and the ball bearings are employed on both sides for supporting the shaft Fig 4 6 4 7 VALVE ARRANGEMENT The intake valve is located on flywheel side of the cylinder head The 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 INTAKE VADE 4 8 CYLINDER HEAD The cylinder head is an aluminum die casting which utilizes wedge type combustion chamber for the highest combustion efficiency Fig 4 8 4 9 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 installed on the main bearing cover 4 10 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 effi ciently 4 11 LUBRICATION
35. g rod smaller end of connecting 3 Remove piston rings from piston rod Do not expand or twist piston rings PISTON RING STEP 25 PISTON PISTON PIN CLIP CLIP CONNECTING ROD CONNECTING ROD CAP M6 FLANGE BOLT 2 pcs 12 2 STEP 24 M7 FLANGE BOLT 2 pcs EH17 2 M8 FLANGE BOLT 2 pcs EH25 2 Fig 5 19 Crankshaft 1 Remove crankshaft tapping at the Be careful not to damage flywheel end oil seal CRANKSHAFT B type CRANKSHAFT D type Fig 5 21 Es 27 Intake valve 1 Loosen nut and remove bolt pivot Inspect valves valve and Exhaust seats and guide valve 2 Remove rocker arms Do not remove valve guides unless they are 3 Press down spring retainer take out collet worn beyond the limit valve and then remove spring retainer shown in page 58 and valve spring 4 Remove intake and exhaust valve See Fig 5 23 BOLT PIVOT M6 NUT ROCKER ARM COLLET VALVE SPRING RETAINER VALVE SPRING DRE VALVE GUIDE 4 INTAKE VALVE EXHAUST VALVE Fig 5 24 Fig 5 23 5 4 REASSEMBLY PROCEDURES PRECAUTIONS FOR REASSEMBLY 1 Clean parts throughly before reassembly Pay most attention to cleanliness of piston cylinder crankshaft connecting rod and bearings 2 Scrape off all carbon deposits from cylinder head piston top and piston ting grooves 3 Check lip of
36. he 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 and which will spark 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 E Power Transistor 5 5 8 gt 5 g Low Speed 5 Ignition 2 x Timing s o Circuit Signal Transistor A Signal Transistor B Control Circuit Automatic Advancing Control Ignition Coil A Fig 6 1 a ELECTRONIC ADVANCING FLYWHEEL MAGNETO SYSTEM B T D C 23 5 STEP ADVANCING 2 9 2 15 500 1000 2000 3000 ENGINE REVOLUTION Fig 6 2 b 44 6 3 WIRING DIAGRAM STANDARD Stop switch Ignition Coil Connector Black Spark Plug Flywheel EINGINE WITH ELECTRIC STARTER STARTER 12VOLT BATTERY MINIMUM 24 AMP HR LIGHT BLUE Fig 6 3 7 AUTOMATIC DECOMPRESSION SYSTEM 12 2 17 2 25 2 engines are employing the automatic decompression system as standard feature This enables easy and light start of the engine The automatic decompression system releases the compression of the engine by lifting up the exhaust valve at the cranking
37. ith lamp coil charge coil and excitor coil 6 2 BASIC THEORY To ensure the easy startability of the engine the step advancing ignition timing system is incorporated in 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 transister it is activated and the current L 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 1 and abruptly shut off the current L 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 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 starts of flow As the engine reaches 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 L and will bypass t
38. l end and piston pin 0 010 0 029 0 0004 0 0011 Big end side clearance 01 07 0 004 0 028 CRANKSHAFT Crankpin outside dia 29 967 29 980 1 1798 1 1803 Journal dia D1 D2 24 988 24 997 0 9838 0 9841 Unit CONNECTING ROD Big end inside dia 34 000 34 016 1 3386 1 3392 34 10 1 3425 0 2 0 008 18 010 18 021 18 08 0 7091 0 7095 0 7118 0 010 0 029 0 12 0 0004 0 0011 0 0047 0 1 0 7 1 0 0 004 0 028 0 040 33 959 33 975 33 85 1 3370 1 3376 1 3327 D TYPE 29 991 30 000 29 988 29 997 1 1807 1 1806 1 1811 1 1 1810 Clearance between big end and crankpin 0 025 0 057 0 0010 0 0022 Small end inside dia Q Clearance between small end and piston pin Big end side clearance 4 A CRANKSHAFT Crankpin outside dia Journai dia E 27 91 30 000 27 288 27 997 1 1019 1 1807 1811 1 1022 65 Unit mm in EH12 2 EH17 2 CAMSHAFT Cam height 29 6 29 8 1 165 1 173 Journal outside dia D 16 973 16 984 16 95 0 6682 0 6687 0 6673 44 973 14 984 14 95 0 5895 0 5899 0 5886 VALVE Valve stem outside dia 5 440 5 455 5 35 0 2142 0 2148 0 2106 5 426 5 444 0 2136 0 2143 Clearance between valv
39. ng AUTOMATIC DECOMPRESSOR SYSTEM RETURN SPRING 4 17 SECTIONAL VIEW OF ENGINE FUEL TANK LEF U s a IN and EX VALVE INTAKE MANIFOLD PISTON IGNITION COIL RECOIL STARTER n PISTON RINGS PISTON PIN POWER TAKE OFF LG ry rii Fh FLYWHEEL MAIN BEARING COVER ROCKER e CD res DOL ERS N lt CONNECTING p m Jes A CARBURETOR he a S TAPPET gt s 7 LA gt exe 7 x RAS 9 CAMSHAFT 5 Ke CRANKCASE SES TA sel Sei 215 AIR CLEANER 5 DISASSEMBLY AND REASSEMBLY 5 1 PREPARATIONS AND SUGGESTIONS 1 When disassembling the engine memorize the locations of individual parts so that they can be reassembed correctly If yor are uncertain of identifying some parts it is suggested that tags be attached to them 2 Have boxes ready to keep disassembed parts by group 3 To prevent losing and misplacing temporarily assemble each group of disassembed parts 4 Carefully handle disassembed parts and clean them with washing oil if necessary 5 Use the correct tools in the correct way 5 2 SPECIAL TOOLS mew m o 209 95004 07 Flywheel puller with bolt For pulling off the flywheel EH25 2 Market parts Flywheel puller For pulling off
40. nt Overhead Valve Lubrication Splash Type Automobile Oil SAE 20 30 or 10W 30 Class SE SF or higher 0 65 L 0 17 U S gal Lubricant Capacity of Lubricant Carburetor Horizontal Draft Float Type Fuel Automobile Gasoline Fuel Consumption Rate 310g KWeh 230 gr HP h At Continuous Rated Output Fuel Feed System Gravity Type Fuel Tank Capacity 3 6 L 0 95 U S gal Ignition System Flywheel Magneto Solid State Spark Plug NGK B6HS 12V 1 3A 12V 1 3A Recoil and Electric Recoil Starter Recoil and Electric Charging Capacity Recoil Starter Starting System Starter Starter Speed Reduction 2 1 Cam Shaft Drive Governor System Centrifugal Flyweight System Dimensions 330 mm 12 99 in 380 mm 14 96 in 380 mm 14 96 in Dry Weight Air Cooled 4 Cycle Single Cylinder Horizontal P T O Shaft Gasoline Engine Bore X Stroke 75 X 57 mm 2 95 X 2 24 in Piston Displacement 251 15 31 Compression Ratio 4 0 5 5 1500 4 7 6 4 1800 4 0 5 5 3000 4 7 6 4 3600 KW HP rpm n 6 3 8 5 2000 6 3 8 5 4000 Max Torque Nem kgf m rpm 33 1 3 38 1300 16 6 1 69 2600 Direction of Rotation Counterclockwise As Viewd From P T O Shaft Side Spark NGK and Electric Recoil and Electric Speed Reduction Speed Reduction 2 1 Cam Shaft Drive Governor System Centrifugal Flyweight System
41. 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 the 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 lapping the shaft with polyvinyl tape to avoid damage to oil seal 2 Install woodruff key for the flywheel on crank shaft CRANKSHAFT 5 4 2 PISTON AND PISTON RINGS 1 Install the oil ring first then second ring and top ring Spread the ring only far enough to slip over the piston and into the correct groove Use care not to distort the ring Install the second ring with the punched mark R or N beside the gap on the top side See Fig 5 29 Fig 5 27 ry MARK EH12 2 EH17 2 N MARK EH25 2 TOP RING SECOND RING OIL RING Fig 5 28 Fig 5 29 5 4 3 PISTON AND CONNECTING ROD 1 When installing the piston on the connecting rod place the valve rcess of the piston crown as SIDE shown in the illustration to the MAG side of the connecting rod Apply oil to the small end of the connecting rod piston and piston pin before installation Be sure to use clips on the both end of the piston pin to secure the pin in po
42. r hole 3 Install the flywheel to crankshaft Tighten the flywheel nut with the starter pulley Fig 5 39 Tightening torque 59 63 Nem 600 650 kg cm 43 47 ftelb 5 4 13 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 0 3 0 5 mm 0 012 0 020 in Tightening torque 8 8 10 8 Nem 90 110 5 4 14 INSULATOR 1 Install the intake pipe to the cylinder head with gasket EH12 2 17 2 M6 flange nut 2 pcs M6 X 25mm flange bolt 1 pe EH25 2 M8 X 28mm bolt and washer gt gt gt 3 pcs Tightening torque 9 8 13 7 Nem 100 140 kg cm 7 2 10 1 Then put the gasket and the insulator on the intake pipe 5 4 15 CARBURETOR Install the gasket and the carburetor to the intake pipe 5 4 16 GOVERNOR SYSTEM sed unl ih ECS 1 Connect the governor lever and the throttle lever on carburetor with governor rod and rod spring Install the governor lever on the governor shatt joel 2 Install the speed control lever to the cylinder head 3 Connect the speed control lever and the governor lever with the governor spring The governor spring should be hooked to the number 2 hole on the speed control lever for the regular specifications Refer to the illustrations below See Fig 5 42 4
43. s required 5 By controling the reel with the thumbs of both Fig 9 1 hands unwind the rope gently until the rota tion of the reel stops WARNING The spring power is at its most when the rope is fully extracted Therefore do not abruptiy put off your hand nor loosen the pressure of your finger unintentionally 2 Setting the attachments off Fig 9 2 1 Fix the case and loosen the set screw 2 Put off the set screw the latchet guide the SET SCREW friction spring and the latchet in the same order from above RATCHET 3 Setting the reel off Fig 9 2 GUIDE 1 Push the reel lightly so that it will not float Ni FRICTION SPRING clockwise about a quarter circle for several times until it moves smoothly 2 Pull up the reel gradually and slowly and put it off from the case 3 case the spring in the reel is close to pop up redo the steps of 3 1 and 3 2 again up Move the reel clockwise and counter RATCHET REEL STARTER CASE WARNING Do not drop or shake the reel and put it on a level table because there is a spring set in the disassembled reel Disassembly is complete Fig 9 2 WARNING Before starting the assembly make sure to wear the protective glasses 9 1 2 Assembly Steps GREASE PASTING 1 Setting the reel into the case 1 Paste grease the case Fig 9 3 2 Adjust the position of the inner end of the spring which is set in
44. sition VALVE RECESS Fig 5 30 2 Install the piston and connecting rod assembly into the cylinder Use a piston ring compressor to hold the piston CONNECTING ROD SIDE rings Place MAG side of the connecting rod on the magneto side of the crankcase PISTON RING COMPRESSOR NOTES 1 Apply enough oil to piston rings connecting rod bearings and cylinder bore before assembly 2 Set gaps of the piston rings 90 degrees apart from each other before assembly SECOND RING ag ye RING 90 TOP RING Fig 5 32 5 4 4 CONNECTING ROD 1 Turn crankshaft to bottom dead center lightly tap top of the piston until large end of the rod meet ALIGNMENT MARK crankpin 2 Install the connecting rod cap to the connecting rod matching alignment marks Torque connecting rod bolts to specification X 34 mm flange bolt 2pcs 12 2 M7 X 37 mm flange 2pcs 17 2 8 X 46 mm flange bolt 2pcs EH25 2 CONNECTING ROD BOLT TIGHTENING TORQUE EH12 2 EH17 2 EH25 2 9 11 N m 17 19 5 Nem 22 27 Nem Fig 5 33 90 115kg cm 170 200Kg cm 225 275 Kg cm 6 5 8 3 ft ib 12 3 14 5 ftelb 16 3 19 9 ftelb 3 Check for free movement of connecting rod by turning crankshaft slowly 5 4 5 BALANCER SHAFT Option for EH25 Install balancer shaft aligning the timing mark on the balancer shaft gear and the balancer gear on th
45. the float chamber through the 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 shuts off the fuel thereby keeping the fuel at the predeter mined level Fig 8 1 PILOT OUTLET PILOT JET RENE Na MAIN JET 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 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 by pass At the 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 may be used for easy start when engine is cold When the engine is cranked with a closed choke the negative pressure applied to the main nozzle increases and draws more fuel accordingly this starting up the
46. the flywheel EH12 2 EH17 2 FLYWHEEL PULLER FLYWHEEL PULLER Fig 5 1 5 3 DISASSEMBLY PROCEDURES OIL GAUGE GASKET Be careful not to lose the 14mm box wrench gasket 2 To discharge oil quickly remove oil gauge 1 Remove oil drain plug and drain oil DRAIN PLUG Fig 5 2 ne oom 2 Fueltank 1 Close fuel valve Wipe off spilt fuel 2 Disconnect fuel hose between fuel strainer thoroughly and carburetor 3 Remove fuel tank from cylinder head 10mm 12mm 6 14mm bolt 4pcs EH12 2 17 2 socket wrench M8X20mm bolt 4pcs EH25 2 M6 BOLT 4 pcs 12 2 17 2 M8 BOLT 4 pes EH25 2 FUEL TANK EE 3 starter 1 Remove recoil from blower housing 10mm box wrench M6x 8mm flange bolt 4 Blower 1 Remove blower housing from crankcase 10mm box wrench housing M6X I2mm flange bolt 4pos Oil sensor 1 Remove oil sensor probe Be careful not to damage stick and sensor since these are Option sensitive and an erratic operation may result lt BE Ce RECOIL Fig 5 4 m Muffler cover 1 Remove muffler cover and exhaust pipe Be careful not to lose 8mm 10mm and Muffler and cover muffler gasket 12mm socket wrench Exhaust pipe 6 10mm flange bolt Specs cover 2 Remove muffler from crankcase and cylind
47. the fuel may become too rich and cause engine malfunction b The bolt tightening torque is 70kg cm Be sure to set the gasket 19 and washer 18 for chamber 13 8 2 5 FLOAT SYSTEM 1 Pull out the float pin 20 and remove the float 21 and then remove the clip 22 and needle valve 23 If the needle valve needs to be replaced replace it with rubber needle When cleaning the jets be sure to use compressed air to blow them clean Never use a drill or a wire because of possible damage of the orifice which will considerably affect fuel flow 2 When removing the needle valve and float 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 9 STARTING SYSTEM 9 1 RECOIL STARTER Equipments to be prepared Driver Pinchers Pliers and Protective Glasses WARNING Before starting the disassembly make sure to wear the protective glasses 9 1 1 Disassembly Steps 1 Setting off the spring power 1 Hold the starter knob and extract the starter 2 Extract the rope fully and hold the rope so that the knob of the rope in the reel makes a dicrect line with the rope guide 3 Push and hold the reel with the thumbs of both hands firmly so that the rope will not be wound back Fig 9 1 4 Pull off the knot of the rope out of the reel unfasten the knot and pull it off to the direc tion of the starter knob 2 person
48. uctions carefully 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 mehtod of supporting the engine When determining its mounting position in particular make sure that gasoline oil 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 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 he hot air used for engine cooling and temperature rise of the machine Keep the engine room temperature below 50 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
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