I . SPECIFICATIONS Model Bore Stroke Piston Displacement Max. Torque Nem (kaf*m)/rDm Direction of Rotation Cooling system Valve Arrangement Lubrication ~~~~~ Lubricant Capacity of Lubricant Carburetor Fuel Feed Fuel Fuel Tank Capacity Spark Plug Charging Capacity Speed Reduction Governor System Dry Weight Length EH12-2B...
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Model TY Pe Bore Stroke Compression Ratio Continuous Output Kw (HP)/rpm Max. Max. Torque (kgf*m)/rpm Direction of Rotation system Cooling Arrangement Valve Lubrication Lubricant Capacity of Lubricant Fuel Fuel Consumption Rate Fuel Feed System Fuel Tank Capacity Spark Plug Charging Capacity Starting System Speed Reduction Dry Weight...
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Model T Y Pe Bore Stroke Piston Displacement Compression Ratio Continuous output (HP)hm Max. Max. Torque Nom (kgf*m)/rpm Direction Rotation Cooling system Valve Arrangement Lubrication Capacity of Lubricant Carburetor Fuel Fuel Consumption Rate Fuel Feed System Fuel Tank Capacity Ignition System Spark Plug Charging Capacity Starting System...
2-1 MAXIMUM OUTPUT The maximum output is the output of an engine with its throttle valve fully opened under the condition worn that all the moving parts are properly 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...
FEATURES 1. The overhead valve design offers resulting in more power from Iess fuel and prolonged engine life. optimum lubrication and better tilted operation thanks to upright cylinder design. 3. A crossflow arrangement of intake and exhaust ports ensures stable performance under high ambient temperature.
CRANKSHAFT The crankshaft is forged carbon steel, and the crank induction-hardened. The output end of the shaft has a crankshaft gear, and EH25-2 which are pressed into balancer gear for position. 4 4 CONNECTING ROD AND PISTON The connecting rod is an aluminum alloy diecasting, and its large and smalI ends function as bearings.
4-6 CAMSHAFT The camshaft the D-type engine 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 forged carbon steel and also functions as PTO shaft.
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 for the inlet and exhaust area cooling air capacity and cylinder.
4-13 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 easy starting, good acceleration, low fuel consumption and sufficient output. 4-14 AIR CLEANER The air cleaner is a single urethane foam element system.
4-16 DECOMPRESSION SYSTEM An automatic decompression mechanism which AUTOMATIC DECOMPRESSOR SYSTEM opens exhaust valve before the piston reaches com- pression top is assembled on the camshaft for easy starting. Fig. 4-14...
DISASSEMBLY AND REASSEMBLY 5-1 PREPARATIONS AND SUGGESTIONS 1) When disassembling the engine, memorize the locations reassembed correctly. If yor are uncertain 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. Carefully handle disassembed parts, and clean them with washing oil if necessary.
5-3 DISASSEMBLY PROCEDURES Part to remove Step Oil drain Remove oil drain plug and drain oil. (2) To discharge oil quickly, remove oil gauge. Procedures Be careful gasket. GASKET Fig. Remarks Tool not to 14mm wrench lose the DRAIN PLUG...
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Part to remove Step Fuel tank Close fuel valve. (2) Disconnect fuel hose between fuel strainer and carburetor. (3) Remove fuel tank from cylinder M6X14mm bolt M8X20mm bolt Procedures Wipe off spilt fuel thoroughly. head. 4pcs. (EH12-2,17-2) * . - - 4pcs.
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Step Part to remove Recoil starter (1) Remove recoil from blower housing. (1) Remove blower housing housing M6X i2mm flange bolt Oil sensor (1) Remove oil sensor probe. (Option) to damage stick and sensor since these are sensitive and result. Procedures 4pcs.
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)art to remove Procedures Muffler cover, (1) Remove muffler cover and exhaust pipe Muffler and cover. Exhaust pipe M6X lOmm flange bolt muffler cover ( 2 ) Remove from crankcase and cylinder head. M8 nut 2pcs. 12mm flange bolt (EHl2-2,17-2) M8X 16mm flange bolt pcs.
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Control box Disconnect wires. and Electric blue light blue (Option) black * * * (2) Remove black wires from electric starter. (3) Remove control Loosen starter. M8 bolt Procedures 1 (diode rectifier ) (diode rectifier (magnetic switch) box. Fastened together with fuel tank.
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Head cover (1) Remove head cover from crankcase. 12mm flange bolt cleaner Remove cleaner cover and cleaner element. (2) Remove cleaner case. M6 flange nut Procedures Fastened together with carburetor. 2pcs. .GASKET CLEANER CASE Fig. Remarks Tool 1 Omm socket wrench lOmm socket wrench...
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Step to remove Part Governor (1) Unhook lever, control lever. Governor rod (2) Remove governor and Governor shaft. spring M6X30mm bolt and washer (3) Detach governor lever, governor rod and rod spring from carburetor. Carburetor Remove carburetor from intake pipe. Speed control (1) Remove lever...
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“ Ignition coil Disconnect ignition plug cap and remove ignition coil M6X25mm bolt and washer ” Remove starter pulley Place socket wrench on flywheel fastening nut and strike tip of the lever hammer. Refer to the illustration below. (See Fig. 5-9.) 14mm nut 18mmnut...
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Part remove Step Remove flywheel Flywheel (2) Remove key from crankshaft. illustrated below. (See Fig. 5-12.) Remove charge Charge coil 25mm Screw (Option) Remove spark Spark plug Procedures crankshaft. Use flywheel puller from (See Fig. coil. 2pcs. cylinder head. plug from FLYWHEEL - 25 Remarks...
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Part to remove step Rocker cover (I) Remove rocker cover from cyIinder head. M6X 12mm flange bolt Remove gasket. (rocker cover) Cylinder head (1) Remove cylinder head from crankcase. M8x65mm flange bolt MIOX75mmflangebolt (EH25-2) (2) Detach cylinder head gasket from cylinder head.
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Step Part to remove (1) Remove main bearing Main bearing bolts. cover M6X30mm bolt and washer M8X30mm bolt and washer Remove main bearing cover using plastic hammer. (See Fig. 5-15) Fig. 5-15 MAIN Procedures cover fastening Be careful not to damage oil seal.
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to remove Step Part Cam shaft and Remove cam shaft from crankcase. Balancer shaft Remove balancer shaft. (Option for (Option for EH25-2) Tappet Remove tappets from crankcase. Procedures To prevent tappets from getting damaged, put the EH25-2) crankcase upside down. (See Fig.
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Step Partto remove Connecting (1) Remove connecting rod bolt after scraping off carbon from Piston 34mm flange bolt M7X37mm flange bolt 2pcs. (EH17-2) M8x46mm flange bolt (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.
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Remarks Part to remove Procedures Too! Step Crankshaft Remove crankshaft at the Be careful not to damage tapping flywheel end. oil seal. Fig. 5-20 CRANKSHAIT (D type) 5-21 fig.
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remove Step 'art to Intake valve Loosen nut and remove bolt (pivot). and Exhaust (2) Remove rocker arms. valve (3) Press down spring retainer, take out collet valve, and then remove spring retainer and valve spring Remove intake and exhaust valve. .(See Fig.
5-4 REASSEMBLY PROCEDURES 0 PRECAUTIONS FOR REASSEMBLY 1) Clean parts throughly before reassembly. Pay most attention to cleanliness of piston, cylinde :r, crankshaft, connectin Scrape all carbon deposits from cylinder head, piston top and piston ring grooves. Check lip of oil seals. Replace oil Apply oil to the lip before reassembly.
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5-28 Fig. 5-4-3 PISTON AND CONNECTING, (1) When installing the piston on the connecting rod, of the piston crown place the valve rcess shown in the illustration to the connecting rod. Apply oil to the small end piston and piston pin before installation. Be sure to use clips on the both end of the piston secure the pin in position.
( 2 ) Install the piston and connecting rod assembly into the cylinder. Use a piston ring compressor rings. Place side of the connecting rod on the “MAG” magneto side of the crankcase. [NOTES] Apply enough oil to piston rings, connecting bearings cylinder assembly.
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BALANCER SHAFT (Option for EH25) 5-4-5 Install balancer shaft aligning the timing mark balancer shaft gear and the balancer gear crank shaft as shown in the illustration. Incorrect timing matfunction the engine and damage due to interference of the parts. 5-4-6 TAPPET AND CAMSHAFT (1) Oil the tappets and install them in their original position.
CRANKSHAFT END PLAY (For 5-4-7-1 (1) Measure the depth “ A l ” (From the mating surface to the inner race of the ball bearing.) (2) Measure the height “ B l ” (From the mating surface to the crank gear.) ( A l + 0.3) - Bl=SIDE CLEARANCE (mm) (SIDE CLEARANCE) - 0.2=THICKNESS OF CRANKSHAFT (A+ 0.012”)
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MAIN ( 2 ) Lubricate the oil seal and bearing surfaces. Add 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 Tap the cover into place with a soft hammer. Main bearing cover EH12-2, 17-2 EH25-2 Tightening...
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.
( 2 ) Loosen the nut under the rocker arm and turn the bolt rocker arm and the valve stem end. Tighten the nut under the rocker arm. Valve clearance 0.08-0.1 2 mm 0.0031 -0.0047 Check operation of valves by turning crankshaft. Recheck valve clearance.
59-63 COIL 54-13 IGNITION Install the ignition coil the crankcase. gap between the ignition coil and the Adjust the air flywheel using a thickness gauge (filler gauge) and tighten the bolts. Tightening torque 8.8-10.8 Nom 90-1 10 kgecrn 5-4-14 INTAKE PIPE, lNSULATOR (1) Install the intake pipe to the cylinder head with gasket.
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’ 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.) 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.
54-17 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. 5-4-1 8 HEAD COVER Install the head cover to the cylinder head. 12mm flange bolt .
5-5 BREAK-IN OPERATION An engine that has been completely overhauled connecting rod should be throughly 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.
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2) At the higher engine speed Rotation of the flywheel generates the current power transistor, it is activated and the current As the engine reaches the ignition timing, the ignition timing control circuit speed is activated and provides the base current collector current It, and will bypass the current power transistor is turned off.
7. AUTOMATIC DECOMPRESSION SYSTEM EH12-2, 17-2, 25-2 engines are employing the automatic decompression system as a standard feature. This enables easy and light start of the engine. The automatic decompression system releases the compression valve at the cranking. Following are the explanation using type the systems are different for the type “D”...
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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 a constant fuel level during the engine operation. The fuel flows from the fuel tank into the float chamber through the needle valve.
8-1-2 PILOT SYSTEM The pilot system feeds engine fuel during idling low-speed operation. The .fuel is fed through the main jet 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.
8-2-4 MAIN SYSTEM (1) Remove the bolt(l2)and take out float chamber body(l3). (2) From the body (14) remove the main nozzle (17) from the main nozzle (15). (3) Reassembly a)Fasten the main jet securely to the body. Otherwise, the fuel may become too rich and cause engine malfunction.
9. STARTING SYSTEM 9-1 RECOIL STARTER Equipments to be prepared Driver, Pinchers (Pliers) and Protective Glasses WARNING starting the disassembly; 9-1-1 Disassembly Steps (1) Setting off the spring power Hold the starter knob and extract the starter rope. Extract the rope fully and hold the rope that the knob the rope in the reel makes a dicrect line with the rope guide.
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WARNING Before starting the assembly, make sure to wear the protective glasses. 9-1-2 Assembly Steps (1) Setting the reel into the case. -1 :Paste grease on the case. (Fig. 9-3) Adjust the position the inner end spring, which is set in the reel. (Fig. 9-4) -3 :Hold the reel that the shafthook part and the inner end...
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(3) Tightening the set-screw. 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 the reel counter-clockwise 6 times. -2: Set the ree to keep the position, whereby the rope hole the reel and the rope guide make...
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(6) 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. (7) If the spring escapes from the reel when disassembling the recoil, hook the outer end onto the notch of the reel and rewind the spring into the housing.
TROUBLESHOOTING The following three conditionts must be fulfilled for satisfactory engine start. 1. The cylinder filled with a proper fuel-air mixture. 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..
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IGNITION SYSTEM 10-1-3 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. Spark plug cable wet or soaked with oil. (4) Spark plug dirty or wet. (5) Spark plug electrode gap incorrect.
10-5 ENGINE KNOCKS (1) Poor quality gasoline. (2) Engine operating under heavy load at (3) Carbon or lead deposits in the cylinder head. (4) Spark timing incorrect. ( 5 ) Loose connecting rod bearing due (6) Loose piston pin due to wear. (7) Cuases of engine overheat.
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 installing the engine. 11-1 INSTALLING When mounting the engine, carefully examine its position, the method foundation, and the mehtod of supporting the engine.
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 Flatness Valve seat contact width...
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ITEM CYLINDER Inside dia. Roundiness after reboring. Cylindricity after reboring. PISTON Piston size (At skirt in thrust direction) EH 1 Lm it be rebored when the lifference 60.000 60.01 9 letween snd min. (2.3622 2.3630) jiameter .cached to 0.1 :0.004). 60.250 60.269 1 st...
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ITEM inside dia. Roundiness after reboring. Cyiindricity after reboring. PI STON Piston size (At skirt thrust direction) Unit: EH25-2 Lmit be rebored /hen ifference 75.000 75.01 9 letween md min. 2.9528 2.9535) liameter eached to 0.004). 75.250 75.269 Ditto reboring 2.9626 2.9633) 75.500...
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ITEM Ring groove side clearance Piston pin hole Piston pin outside dia. Clearance between piston and cylinder a t skirt area. Piston ring end gap Limit 0.030 0.075 0 . 1 (0.001 2 0.0030) (0.006) 0.030 0.075 0 . 1 (0.001 2 0.0030) (0.006)
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Ring side clearance groove Piston pin hole ~ r n Piston pin outside dia. piston Clearance between cylinder at skirt area. Piston ring Unit: EH25-2 Limit 0.1 5 0.050 0.090 (0.006) 1.0020 0.0035) ~~~~~ 0.1 5 0.030 0.070 ).0012 0.0028) (0.006) 0.010 0.1 5...
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ITEM ZONNECTING Big end inside dia. Clearance between big end and crankpin Small end inside dia. Clearance between small end and piston pin Big end side clearance CRANKSHAR Crankpin outside dia. Journal dia. EH 1 2-2 26.000 2 6 . 0 1 3 (1 -0236 1.0241) 0.020...
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ITEM CONNECTING inside dia. Clearance between big end Clearance between big end and crankpin and crankpin Small end inside dia. Small end inside dia. Clearance between small and piston pin end side clearance CRANKSHAFT Journal dia. EH 1 7-2 30.000 30.01 (1.1811 -1.1817)
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lTEM Clearance between big end and crankpin Small end inside dia. Clearance between small end and piston pin Big end side clearance CRANKSHAFT Journal dia. EH25-2 34.000 34.01 6 (1.3386 1.3392) 0.025 0.057 (0.0010 0.0022) 18.01 0 18.021 (0.7091 0.7095) 0.01 0 0.029 (0.0004...
12-2 TORQUE SPECIFICATIONS EH12-2 17-2 type DESCRIPTION Cylinder head bolts Connecting rod cap bolts Flywheel nut Main bearing cover bolts New spark plug Spark plug Retightening type EH25-2 DESCRIPTION Cylinder head bolts cap bolts Flywheel nut Main bearing cover bolts spark plug Retightening...
12-3 OIL GRADE CHART Comparison between oil viscosity and temparature Single grade Specified Lubrican Quality Multi- grade 40 "C 104 "F Use oil classified or higher. Multi-grade oil tends to increase its consumption at high ambient temperature. - 71...
13. MAINTENANCE AND STORAGE The following maintenance jobs apply when the engine The indicated maintenance intervals are by no means guarantees 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.
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EVERY 100-200 HRS. (MONTHLY) MAINTENANCE 13-4 MAINTENANCE Clean fuel filter and fuel tank. Inspect cooling system and remove chaff. 13-5 EVERY 500-600 HRS. MAINTENANCE MAINTENANCE Remove carbon from cylinder head. Disassemble and clean carburetor. 13-6 EVERY 1000 HRS. (YEARLY) MAINTENANCE MAINTENANCE REMARKS Overhaul engine.
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SU6ARU ~bin America, Inc. 940 Lively Blvd. Wood Dale, IL 60191 Phone: 630-350~8200 Fax: 630-350-8212 e-mail: sale.s@robinamerica.com www.robinamerica.com PRINTED IN THE USA...