OVERHEAD VALVE SIDE VALVE DIESEL ROBIN AMERICA, INC. ROBIN TO WISCONSIN ROBIN ENGINE MODEL CROSS REFERENCE LIST ROBIN

Transcription

1

2 ROBIN AMERICA, INC. ROBIN TO WISCONSIN ROBIN ENGINE MODEL CROSS REFERENCE LIST ROBIN WISCONSIN ROBIN SIDE VALVE EY08 EY15 EY 15V EY20 EY2OV EY23 EY28 EY3 5 EY40 - EY45V EY2 1 EY44 EY 18-3 EY25 EY27 W W1-145 W1-145V W1-185 W1-185V W1-230 W W W Wl-45OV EY21W EY44W EY18-3W EY25W EY27W OVERHEAD VALVE EH11 EH12 EH15 EH17 EH21 EH25 EH30 EH30V EH34 EH34V EH43V WO1-115 wo1-120 WO1-150 WO1-170 wo1-210 WOl-250 WO WO1-300V WO1-340 WO 1-340V WO 1-43 OV TWO CYCLE EC13V WT1-125V DIESEL DY23 DY27 DY30 DY3 5 DY4 1 WRD WRD WRD1-350 WRD1-410

3 CONTENTS Section Title Page 1. SPECIFICATIONS PERFORMANCE Maximum Output Continuous Rated Output Maximum Torque and Fuel Consumption Ratio at Maximum Output FEATURES GENERAL DESCRIPTION of ENGINE CONSTRUCTION Cylinder. Crankcase... 4 Main Bearing Cover... 4 Crankshaft... 4 Connecting Rod and Piston... 5 Camshaft... 5 Valve Arrangement... 5 Cylinder Head... 6 Governor... 6 Cooling... 6 Lubrication... 6 Ignition... 7 Carburetor... 7 Air Cleaner... 7 Sectional View of Engine DISASSEMBLY and REASSEMBLY Preparation and Suggestion Special Tools How To Disassemble How To Reassemble MAGNETO Magneto Magneto Trouble Shooting GOVERNOR ADJUSTMENT CARBURETOR Operation and Construction Disassembly and Reassembly... 27

4 Section Title Page 9. BREAK-IN OPERATION Of REASSEMBLED ENGINE ROBIN SOLID STATE IGNITION ENGINE (U.T.C.I.) Features Basic Principle of U.T.C. I I1. ROBIN OIL SENSOR SYSTEM (FLOAT SYSTEM) Features Basic Principle Checking Procedures Precautions Wiring TROUBLE SHOOTING Starting Difficulties Engine Misfires Enginestops Engine Overheat Engine Knocks Engine Backfires through Carburetor INSTALLATION Installing Ventilation Exhaust Gas Discharge Power Transmission to Driven Machines Wiring CHECKS and CORRECTIONS TABLE of CORRECTION STANDARDS MAINTENANCE and STORING Daily Checks and Maintenance Every 20 Hours Checks and Maintenance Every 50 Hours (IO days) Checksand Maintenance Every Hours (Monthly) Checksand Maintenance Every Hours (Semiannual) Checksand Maintenance Every 1000 Hours (Yearly) Checks and Maintenance Preparation for Long Abeyance... 46

5 ~~ ~ ~~ 1. SPEC1 FICATIOMS Model EY08D EY08BN Air-Cooled, 4-Cycle, Vertical, Single Cylinder Gasoline Engine Bore x Stroke (in) Piston Displacement (cu. in) 51 mm 'x 38 mm (2.01" x 1.50") 77.6 cc (4.74 cu. in) Compression Ratio 6.5 Continuous Rated Output (HP/rpm) Max. Output (HP/rpm) Max. Torque (kg-m/rpm) 1.0/ / / / O? / / /1600 Direction of Rotation 1 Counterclockwise Facing to P.T.O. Shaft Clockwise Facing to P.T.O. Shaft Cooling System I Forced Air Cooling Lubrication Lubricant Carburetor Fuel Fuel Consumption Ratio (gr/hp-h) Splashing Type Automobile Oil Class SC Horizontal Draft, Float Type Non-leaded Automobile Gasoline 320 at continuous rated output operation Fuel Feed I Gravity Type Fuel Tank Capacity I Approx. 1.5 liter (0.40 U.S. gal.) Reduction Ratio I - 1 /2 Speed Governor System Spark Plug Lighting Capacity (V-W) Starting System Centrifugal Flyweight Type Flywheel Magneto Type (Solid State Ignition) Ignition NGK-BM4A (S.T.D.) - Recoil Starter Dry Weight (Ibs.) 8 kg (17.6 Ibs.) 8.5 kg (18.7 Ibs.) Dimensions Length (in) Width (in) Height (in) 252 mrn (9.92") 264 mm (10.39") 326 mm (12.83") -1 -

6 2. PERFORMANCE 2-1 MAXIMUM OUTPUT The maximum output of an engine is such standard power as developed by the engine, after its initial break-in period with all the moving parts properly worn in, when operating with a fully open throttle valve, Therefore, a new engine may not develop the maximum output in the beginning because the moving parts are not in a properly worn-in condition. 2-2 CONTINUOUS RATED OUTPUT The continuous rated output of an engine is such power as developed by that engine when running continuously at an optimum speed, and most favorable from the viewpoint of engine life and fuel consumption ratio, with the governor in operation. It is suggested, therefore, that when designing a driving system for any mechanism, with this engine as prime mover, the continuous power requirement of that mechanism be kept below the continuous rated output specified. 2-3 MAXIMUM TORQUE and FUEL CONSUMPTION RATIO at MAXIMUM OUTPUT These mean the maximum torque of the output shaft and fuel consumption ratio at the maxiumum output of an engine. PERFORMANCE CURVE MODEL EY08D ( ) for BN type 0.45 (0.9) kg-rn L W 0 a HP 3 L 0 I o (1000) (1500) - (2000) Revolution r.p.m. -2-

7 3. FEATURES 1. Compact, lightweight, durable, powerful 4cycle air cooled engine embodying ingenious design techniques and skilful workmanship. 2. Simple construction, smart appearance, maximum easiness of start owing to automatic decompression device 3. Pointless Solid State ignition system is newldy adopted for preventing poor igniting. 4. Reliable prime mover for varietyof purposes with smooth speed controlrby a governor under varying load conditions. 5. Economical because fuel consumption is very low -3-

8 4. GENERAL DESCRIPTION of ENGINE CONSTRUCTION 4-1 CYLINDER, CRANKCASE The cylinder and crankcase are single piece aluminum die casting. The cylinder liner, made of special cast iron, is built into the alminum casting. The intake and exhaust ports are located on one side of the cylinder, and are also inserted into the casting. The crankcase is separable on the output shaft side, where the main bearing cover is attached to it. (See Fig. 1.) 4-2 MAIN BEARING COVER Fig. 1 The main bearing cover made of aluminum die casting is built onto the output shaft side of the crankcase so that the inside of the engine can readily be checked by simply removing the cover. It is provided with a flange and boss for directly mounting machines, such as generators and pumps. Two oil gauges also serving as oil filler caps can be mounted. (See Fig. 2 and Fig. 3.) Ring for Centering Oi I!ID Oil Gauge Fig. 2 ~~ Fig CRANKSHAFT The crankshaft is forged of carbon steel, and the crankpin is induction-hardened. It has a crank gear pressure-fitted on the output end. (See Fig. 4.) Induction Hardening (Portion of Crankpin) \ Crank Gear (Pressure-fit) Fig. 4-4-

9 :Fig CONNECTING ROD and PISTON The connecting rod is made of aluminum die casting, which itself serves as bearings at both the large and small ends. The large end cap and the oil scraper are moulded in a unit for splashing the lubricating oil. The piston is cast of aluminum alloy, and has grooves for receiving two compression rings and one oil ring. (See Fig. 5.) Top Ring Second Ring Oil Ring Connecting Rod L \I Fig. 5 Oil Scraper 4-5 CAMSHAFT In the EY08D engine, the camshaft is integrally built with a cam gear of special cast iron, and has intake and exhaust cams. Also the camshaft has aluminum plain bearings attached to both ends. (No ball bearing is used.) (See Fig. 6.) In the EY08BN engine, the camshaft is forged of carbon steel and is provided with a force-fit cam gear. It serves also as the driving shaft, being driven at half the crankshaft speed, and a ball bearing is used at the P.T.O. shaft side. 4-6 VALVE ARRANGEMENT The intake valve is located upstream of the cooling air with the result that the carburetor is intensively cooled. (See Fig. 7.) Direction of Cooling Wind Fig. 7-5-

10 4-7 CYLINDER HEAD The cylinder head is an aluminum die casting, and forms a Ricardo type combustion chamber with ample area for high combustion efficiency. (See Fig. 8.) I Fig GOVERNOR The governor is a centrifugal flyweight type which permits constant operation- at the selected speed against load variations. Govrnor gear is installed on the bearing cover without fail, and it engages with the cam gear after reassembling. (See Fig. 9.) Main Be Spacer - Governor Gear Complete Q!mor Sleeve Fig COOLING The cooling fan serving also as a flywheel cools the cylinder and the cylinder head by forced air cooling. Cylinder baffles and head cover are provided for guiding the cooling air LUBRICATION The rotating and sliding parts are being lubricated by scooping and splashing the oil in the crankcase with the oil scraper. (See Fig. 10.) Fig

11 4-11 IGNITION The ignition system is a flywheel magneto type with ignition timing set at 25" before TDC. The magneto is composed of a flywheel and ignition coil. The flywheel serving also as a fan is mounted directly on the crankshaft, and the ignition coil in the crankcase. (For further details, refer to Section on the Magneto.) (See Fig. 1 1.) I Ignition Coil Fig CARBURETOR A horizontal draft carburetor is employed. It has been carefully set after thorough tests to assure satisfactory start up, acceleration, fuel consumption, output performance, etc. For construction and order details, refer to the Section on Carburetor Construction, Disassembly and Reassembly. (See Fig. 12.) Fig AIR CLEANER The air cleaner of the standard ty :ngine is an 0 b- long type using a sponge element. (A cyclone type semi-wet double element air cleaner is optionally available.) (See Fig. 13.) Air Cieaner for Standard Type Cyclone Type (Option) Fig

12 4-14 SECTIONAL VIEW of ENGINE MODEL EY08D -8-

13 Air Cleaner Stop Button Carburetor Connecting Rod Intake and Exhaust Valve Tappet Crankcase Camshaft Governor Shaft MODEL EY08D -9-

14 5. DISASSEMBLY and REASSEMBLY 5-1 PREPARATIONS and SUGGESTIONS 1) When disassembling the engine, remember well the locations of individual parts so that they can be reassembed correctly. If you 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 missing and misplacing, temporarily assemble each group of disassembed parts. 4) Carefully handle disassembed parts, and clean them with washing oil. 5) Use the correct tools in the correct way. 5-2 SPECIAL TOOLS For your reference, the following shows special tools of Robin Engine for Disassembly, Measuring and Inspection Instruments. Part No. Tool Use Applicalbe Model Shape EY08 EY10, 13, Flywheel Puller (with bolt) For pulling off Flywheel EY 15,18, 20 EY23, 25, 27, EY33 EY35,40,44 EC05.07, 10 EC17, EY Valve Spring Retainer For mounting and dismounting Valve Spring Retainer and Retainer Lock EY10,13, 14 EY 15, 18,20 EY23 EY25.27, 33 EY35,40, EY Valve Guide Puller For pulling off Valve guide EY10 EY13,

15 Part No. Tool Use Applicalbe Model Shape EY Valve Guide Puller For pulling off Valve guide EY 15,ZO EY25, 27 EY10, 13, 14 EY 15, 18,20 EY25,27, Timing Tester For adjusting timing EY35,40,44 EC03,04,05 EC07,10, 17 EC25,

16 5-3 HOW TO DISASSEMBLE *Length of the bolt indicates the length from the bolt head bottom surface to the threaded end. Order I tern Procedures Remarks Tool Fuel tank (1) Close the fuel cock. (2) Disconnect the fuel pipe between the fuel strainer and carburetor at the carburetor side. (3) Remove the fuel tank from the tank bracket. M6 x 14 mm bolt : 3 pcs. Sems bolt 10 mm box spanner Recoil starter (1) Remove the recoil starter. M6 x 8 mm bolt : 3 pcs. IO mm box spanner Tank bracket Head cover Fan cover (1) Remove the tank bracket, the head cover, and the fan cover from the crankcase and the cylinder head. M6 x 10 rnm bolt : 2 pcs. M6 x 12 bolt : 1 pce. M6 nut : 2 pcs. Fastened together Remove the primary wire of the stop button. 10 m box spanner Ir 10 mm spanner Muffler cover Muffler (1) Remove the muffler cover 1 from the muffler. M6 x 8 mm bolt : 2 pcs. (2) Remove the muffler from the cylinder portion of the crankcase. M6 x 28 mrn bolt : 1 pce. M6 x 50 mm bolt : 1 pce. 10 mm box spanner x 10 mm spanner 5 Air cleaner (1) Remove the air cleaner cover and the element. (2) Remove the air cleaner case from the carburetor. M6 nut : 2 pcs. (3) Disconnect the breather pipe. Air cleaner is fastened together with the carburetor. 10 mm box spanner ) - - {,Governor Rod Spring Governor Lever Governor Rod Governor Spring L Lock Bolt Governor Shaft Fig. 14 Lever ' High Speed Set Screw

17 ~ ~~~~~~~~~~~ ~ ~~ Order Itern Procedures I Remarks I Too I 6 Governor lever and the relative parts Carburetor (1) Remove the governor Iever from the governor shaft. M6 x 25 mm bolt : 1 pce. (2) Remove the governor rod and rod spring from the carburetor. (3) Remove the carburetor from the cylinder portion of the crankcase. Just loosen the bolt, unnecessary to take out the bolt. 10 mm box spanner or 10 mm spanner Starting pulley Flywheel (1) Remove the starting pulley from the fly- Be careful not to wheel. damage the blades of M12 nut : 1 pce. the flywheel with a Fit a box or socket wrench over the flywheel nut, and strike it hard with a hamdriver and a like. Strlke counterclockmer to remove the nut and spring washer. wise with a hammer. (See Fig. 15) (1) Remove the flywheel from the crankshaft. Fit the flywheel puller as shown in Fig. 16, turn the center bolt clockwise and pull out the flywheel. 17 mm box spanner or socket wrench Fig. 15 Fig. 16 Order I tern Procedures 9 Ignition coil (1) Remove the plug terminal from the spark plug and remove the ignition coil from the crankcase. M6 x 25 mm bolt : 2 pcs. 10 (1) Remove the spark plug from the cylinder Spark plug he ad Sems bolt Remarks 710 mm box spanner I19 mm box spanner

18 Order I Item Procedures Remarks Tool 11 Cylinder head I l2 I Intake and exhaust valve (1) Remove the M6 bolts and remove the cylinder head from the crankcase M6 x 32 mm bolt : 5 pcs. M6 x 40 mm bolt : 2 pcs. (2) Remove the cylinder head gasket from the crankcase. (1) Remove the inner and outer tappet covers from the crankcase. M6 x 12 mm bolt : 2 pcs. (2) Pull out the intake and exhaust valve. (3) Remove the valve spring and the valve spring retainer. M6 x 40 mm bolt is special bolt. Put the notch on the outer circumference of the spring retainer on this side. Hook the medium size (-) driver at the dent (lower side) of the spring retainer and pull out the valves, while pulling the spring retainer toward you. (See Fig. 17.) 10 mm box spanner The front is this sidf (-) driver 13 I Main bearing cover (1) From the crankcase remove the bolt fastening the main bearing cover. M6 x 25 mm bolt : 6 pcs. (2) Remove the cover, lightly tapping the cover evenly with a plastic hammer. Sems bolt Be careful not to damage the oil seal. (See Fig. 18.) 10 mm box spanner \ (-) Driver \ Main/Bearing Cover I Plastic Hammer Fig. 17 Fig

19 ~~~ ~~~~ ~~~ ~~ Procedures I Remarks I Too I (1) Remove the camshaft from the crankcase. To prevent the tappets from falling or damaging, place the crankcase on the side. (See Fig. 19.) 15 Tappet I (1) Remove the tappets from the crankcase. Before removing put a mark of intake or exhaust on each tappet. Camshaft Order I tern Procedures Remarks I Tool 16 Connecting rod and piston (1) Scrape off carbon and other foreign deposits from the upper parts of the cylinder and piston, and then straighten out the bent tabs of the lock washers on the connecting rod, and remove two pieces of the bolt. (2) Remove the lock washer and the connecting rod cap from the crankshaft. (3) Turn the crankshaft until the piston is raised up to the hghest position, push the connecting rod up, and remove the piston out of the top of the cylinder. Pay attention to the direction of the connecting rod cap. 8 mm box spanner or 8 mm spanner 17 Piston and piston pin (1) Remove the two clips, pull out the piston pin, and take the piston off from the small end of the connecting rod. (2) Spread the open ends of the piston rings and remove them from the piston. Be careful not to damage the inside of the small end of the connecting rod. Be careful not to break the rings by spreading too much. 18 Crankshaft (1) Remove the woodruff key (for the magneto). (2) Lightly hammer the magneto end of the crankshaft, and pull it out of the crankcase. Be careful not to damage the oil seal

20 5-4 HOW TO REASSEMBLE.Precaution in reassembling Every and each part should be cleaned thoroughly. Especially, pay utmost care and attention to the cleanliness of the piston, cylinder, crankshaft, connecting rod and bearings. Scrape completely off carbons from the cylinder head and the upper part of the piston; especially the carbon adhered in the groove of the piston ring should be carefully and completely taken out. Carefully check the lip portion of every oil seal. If faulty one is found, replace it without any hesitation. Apply enough oil to the lip portion of the oil seal when reassembling. Replace all the gaskets with new ones. Replace the key, pin, bolt, nuts, etc. with new one, if necessary. Whenever tightening torque is specified, conform to the specified figures. Apply oil to the revolutionary parts and friction surfaces, when reassembling. Check and adjust the clearances of various portions and then reassemble. When some main portions are assembled in the course of reassembling, turn or move the gadgets by hand and pay attention to the frictional noise and resistance. *Sequence and precautions in reassembling GOVERNOR SHAFT 1) Insert the governor shaft into the crankcase. 2) Place the clips on the governor shaft CRANKSHAFT 1) Inser the crankshaft into the crankcase as shown in Fig Note: Be careful not to damage the oil seal lip. 2) Put woodruff key (for magneto) in place. Shaft Fig

21 3) Dimensions of Crankshaft Pin D (Crankshaft Pin Dia.) 20 dia W (Crankshaft Pin Width) PISTON TO CYLINDER AT PISTON SKIRT THRUST FACE tx"--+ I TOP, SECOND PISTON RING GAP PISTON RING CLEARANCE IN GROOVES 0.008L L 0.2 L - 0.4L 0.05L L (Cutter Ring) i TOP RING SECOND RING OIL RING 0.09OL L 0.060L L 0.01OL L (Cutter Ring) CONNECTING ROD TO CRANK PIN CONNECTING ROD TO PISTON PIN PISTON PIN TO PISTON DIA 0.037L L 0.1 L - 0.7L 0.010L L 0.009T OL Fig. 21 L: LOOSE T: TIGHT - 17-

22 5-4-3 PISTON and PISTON RING 1) If no ring expander is available, install the rings by placing the open ring ends over the first land of the piston and spreading the rings only far enough to slip them over the correct ring grooves. Note: Pay attention not to break the rings by twisting. Install the oil ring first followed by the second ring and then top ring. Meantime, the surfaces of the second ring and the top ring with carved carved marks are to be faced up. Note: When replacing the piston rings with new ones, install the rings for replacement as shown in Fig. 22. STD I Replacement Parts I Top Ring Taper Taper I I Second Ring Taper Undercut Q l Oil Ring 2) Reassemble the piston and the connecting rod by means of the piston pin. Note: Apply enough oil to the small top end of the connecting rod. Be sure to place the clips on both ends of the piston pin. Fig. 22 Assembly type a Cutter Ring n 3) When installing the connecting rod into place, hold piston rings with the ring guide as shown in Fig. 24 (if no ring guide is available, keep pressing the piston rings with finger tips and gently strike the top of the piston with a wooden piece or the like to push it in), and check that the or mark MA on the connecting rod is i the direction of the flywheel magneto. Note: Apply enough oil to the piston rings, connecting rod plain bearings and cylinder wall before reassembling. Note: The open ends of the piston rings must be 90" apart from one another on the piston periphery. Note: The clearance between the piston and cylinder must be measured at the piston skirt thrust surface Fig. 23 Fig, 24 Crank Case (Magneto Side)

23 5-4-4 CONNECTING ROD 1) Turn the crankshaft to the bottom dead center, lightly hammer the piston head until the connecting rod contacts the crankpin, and assemble. 2) When reassembling the connecting rod cap, set it so that the oil scraper is in the right.bottom. (See Fig. 25.) Note: Use new lock washers, and bend the tabs securely, Note: After reassembly, confirm that the connecting rod moves lightly. Note: Connecting rod cap tightening torque: kg-cm Note: For the piston, piston ring and- rod clearance, see Fig Fig TAPPET and CAMSHAFT Insert the tappets back into their holes first, and then mount the camshaft. Note: Align the timing mark at the root of a tooth of the camgear with the one on the crank gear. If the valve timing is wrong, the engine cannot operate properly or at all. (See Fig. 26. ) Note: If the intake tappet and exhaust tappet were assembled contrarily each other, the tappet clearance cannot be kept correctly. Fig

24 5-4-6 MAIN BEARING COVER Install the main bearing cover to the.crankcase. Note: As the'governor gear is mounted on the main bearing cover side, install the main bearing cover while checking that it meshes with the teeth of the cam gear. (See Fig. 27.) Meantime, if the oil seal need be replaced, pressure-fit a new oil seal before installing the main bearing cover. -1 Pay attention to the engagement of the governor ear and cam gear. I t Fig. 27 Note: When installing main bearing cover, apply oil to the bearing and oil seal lip. Fit the oil seal guide over the crankshaft or camshaft to protect the oil seal lip from damage. Then place the main bearing cover on. Check the crankshaft if its side clearance is mm; and if not, adjust it with the adjusting shim. (See Fig. 28,) Note: In the BN type, adjust the side clearance of the cam shaft with the adjust shim so that it is from 0 to 0.2 mm. Fig. 28 Note: Main bearing cover tightening torque: kg-cm * - * Dial Indicator Note: Fig. 29 shows one of the methods measuring the crankshaft side clearance between the machined face of the crankcase and adjusting Ground Surface of collar. As a paper packing is used on the machined face of the crankcase, adjust the clear- (The surface of the crankcase is to be put together with the surance by taking this thickness of0.22 mm into face of the main bearing cover.) account. (See Fig. 29.) 1 ( Fig

25 5-4-7 INTAKE and EXHAUST VALVES Remove carbon and gum deposite from the valves, valve seats, intake and exhaust ports and valve guides, Note: If the valve face is dinted or warped, replace the valves with new ones. Note: If there is an excessive clearance between the valve guide and valve stem, replace the valve guide with a spare. For replacing, pull out the valve guide, using the valve guide pulling base and bolts as shown in Fig. 30, and pressure-fit a new valve guide into place. Valve Face I % Spring Retainer Fig. 30 VALVE and VALVE GUIDE CLEARANCE ACE A-VALVE I 45" I I B- SEAT ANGLE I 45" I C-GUIDE INSIDE DIA. 5.5 dia INTAKE 0.020L L I CLEARANCE MAXIMUM ALLOWABLE BETWEEN C and D EXHAUST 0.056L L Fig. 31 L: LOOSE

26 5-4-8 TAPPET ADJUSTMENT Lower the tappet all the way down, push the valve, and insert a thickness gauge between the valve and tappet stem to measure the clearance. (See Fig. 32.) Note: The correct tappet clearance for both intake and exhaust valves is 0.1 mm k0.02 mm as measured when the engine is cold. I Valve Thickness Gauge Valve Spring Valve Spring Retainer Fig. 32 fig Note: If the clearance is smaller than specified, slightly grind the top of the valve stem, and measure it again. On the contrary, if the clearance is too large, replace the valve with new one, and polish its contact surface with a compound to obtain a good fit. Then adjust the clearance. Note: After the tappet clearance adjustment, install the valve springs and the valve spring retainers, and turn the crankshaft, and measure the tappet clearance once again if it is correct. n Note: INSTAL LA TION of SPRING RETAINERS Place the notch on the outer circumference of the retainer toward this side and insert the retainer, like pushing in, using a special tool. lf a driver is used, insertion may be easier. \-I Driver \ Valve Spl k g l Retainer Front should be this side. Fig CYLINDER HEAD Remove carbon from the cylinder head, particularly its combustion chamber, and make clean the cooling fins. Also check the head for distortion. Note: Replace the cylinder head gasket with a new one. Note: Cylinder head tightening torque: kg-cm /

27 SPARK PLUG Tightening torque of the spark plug: kg-cm. Note: If the spark plug is new, tighten the spark plug at kg-cm torque IGNITION COIL, FLYWHEEL and STARTER PULLEY 1) Temporarily fasten the ignition coil to the crankcase, and install the flywheel to the crankshaft. Starting pulley is fastened together with the flywheel. Note: Before installing, wipe out oil from the crankshaft and the tapered portion of the flywheel. Note: Before installing the starting pulley, check if the woodruff key is correctly inserted. Note: Flywheel tightening torque: kg-cm. 2) After measuring the air gap between the ignition coil and flywheel, retighten the ignition coil. (See Fig. 35.) Air gap: mm I Fig CARBURETOR To the cylinder portion of the crankcase install in the order of the gasket, insulator, gasket and carburetor, and then mount the air cleaner case and fasten with two pieces of M6 nut GOVERNOR LEVER When reassemblying, refer to the 7. GOVERNOR ADJUSTMENT MUFFLER and MUFFLER COVER Install the muffler cover 2 to the muffler and fasten the muffler to the crankcase and then install the muffler cover 1. Note: Muffler tightening torque: kg-cm Note: Clamp the muffler and tighten the bolts after engine the has been fully cooled HEAD COVER, FUEL TANK, FUEL TANK BRACKET and FAN COVER Install in the order of the head cover, fan cover, fuel tank bracket and fuel tank. Note: Install the grommet of the ignition coil to the head cover before installing the fan cover RECOIL STARTER With 3 pieces of M6 x 8 mm bolt fasten the recoild starter. Note: It is feared that the bolt longer than 8 mm may damage the blade

28 I 6. MAGNETO 6-1 MAGNETO The spark for ignition is furnished by the magneto assembly. The magneto consists of the flywheel and the ignition coil of which flywheel is mounted on crankshaft and ignition coil is mounted in crankcase directly. /- 6-2 MAGNETO TROUBLE SHOOTING When the engine does not start or starts with difficulty, or when its operation is unstable, the following tests will clarify if they are caused by a defect in the magneto. 1) Check ignition cable for possible corrosion, broken, worm insulator or lose connection. 2) Check the sparking as described later in this section. 3) If no spark takes place, replace ignition coil. *SPARK TESTING Remove the spark plug from the cylinder head and place it on the cylinder head, with the ignition cable connected to it. Crank the engine several times by recoil starter and observe the spark in the spark gap of spark plug. If the spark is strong, the ignition system can be eliminated as the source of trouble. (Remove the primary wire from the connector.) If the spark is weak or there is no spark at all, repeat the checks. The correct electrode gap is mm. (Refer to section 14. CHECKS and CORRECTIONS. ) Flywheel Fig. 36 /

29 7. GOVERNOR ADJUSTMENT Model EY08 emploies a centrifugal flyweight type governor. The governor is mounted on the govenor gear and the throttle valve of the carburetor is automatically regulated by a lever which is connected to the gover- nor in order to maintain constant engine speed against load variations. The adjustment procedure of the governor is as follows (See Figs ): 1) Connect the carburetor throttle lever to the governor lever with the governor rod and the rod spring and mount the governor lever onto the governor shaft. 2) Install the speed control lever to the crankcase. 3) Connect the governor lever to the control lever with the governor spring. Governor Lever Governor Rod Governor Spring Governor Shaft Fig. 37 4) Turn the control lever towards high speed, and confirm that the carburetor throttle valve is fully opened. Control lever can stay wherever it is required. *Position to hang the governor spring The standard position is 2-A. But, in case of a 50Hz generator, the governor should be hung at 3-B. An example of the governor spring being hooked. Fig. 38 5) With a screwdriver in the groove of the governor shaft, turn it clockwise fully until the governor shaft no longer moves, and then look the governor lever to the governor shaft with the governor lever tightening bolt. (See Fig. 39.) Governor Lever Fig

30 8. CARBURETOR 8-1 OPERATION and CONSTRUCTION (See Fig. 40.) FLOAT SYSTEM The float chamber is located just below the carburetor body and, with a float and a needle valve, maintains a constant fuel level during engine operation. The fuel flows from the fuel tank into 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 close to the shut off the fuel, thereby keeping the fuel at the reference level. Pilot Jet,,,"--Pilot Air Jet r Pilot Jet Main Air Jet /- Needle Valve Float - fig

31 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. During engine idling, the fuel is mainly fed from the pilot outlet MAIN SYSTEM The main system feeds the fuel to the engine during 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 CHOKE The choke is used for easy start in the cold season. When the recoil starter is pulled 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. 41.) THROTTLE SYSTEM 1) Remove the Philips screw (18) and throttle valve (19), and pull out the throttle shaft (20). 2) The spirng (21) can be taken out by removing the throttle stop screw (22). *Exercise care not to damage throttle valve ends CHOKE SYSTEM 1) Remove the Philips screw (14) and choke valve (1 S), and pull out the choke shaft (1 6). 2) When reassembling the choke shaft, make sure that the cutout in the choke valve faces the main air jet PILOT SYSTEM Remove the pilot jet (23) using correct tool to avoid damage to it. Reassembly Tighten the pilot jet securely. Otherwise, the fuel may leak, causing engine malfunction A Fig

32 8-2-4 MAIN SYSTEM 1) Remove the bolt (12) and take out float chamber body (10). 2) Remove the main jet (13) from the body (6). 3) Reassembly a) 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 70 kg-cm FLOAT SYSTEM Pull out the float pin (9) and remove the float (8) and needle valve (17). If the needle valve need be replaced, replace it with rubber needle. Caution: When cleaning the jets, use neither a drill nor a wire (because of possible damage of the orifice which will adversely affect fuel flow). Be sure to use compressed air to blow them clean. When removing the needle valve and floats, gently tap the reverse side using the rod more slender than the float pin and remove because the float pin is calked to the carburetor body. BREAK-IN OPERATION of REASSEMBLED ENGINE An overhauled engine must be operated at low speed break-in the parts. A thorough break-in is indispensable particularly when the cylinder, piston, piston rings or valves are replaced with new ones. The recommended break-in schedule is shown below. I LOAD SPEED (Crankshafr Rev.) TIME I 2,500 rpm 10 minutes NO LOAD NO LOAD 0.7 PS 3,000 rpm 3,600 rpm 3,600 rpm 10 minutes 10 minutes 30 minutes 1.4 PS 3,600 rpm 60 minutes

33 10. ROBIN SOLID STATE IGNITION ENGINE' (U.T.C.I.) 10-1 FEATURES EY08 emploies a pointless ignition system, called Solid State Ignition, which is the circuit breaker type ignition device, utilizing the power transistor as an element for controling electric current. This ignition system is called U.T.C.I. (Universal Type Transistor Controlled Ignition), and it is based on an external coil system in which an ignition coil is installed outside the flywheel and the unit is mounted on an iron core of the coil. Being different from the breaker point type ignition system, this brand-new system is completely free from such troubles as starting-up failure owing to dirty, burnt or oxidized point surface, lowering of ignition efficiency being caused by moisture, rough surface to breaker point and incorrect timing resultant from worn mechanical parts BASIC PRINCIPLE OF U.T.C.!. (See Fig. 42.) Electricity is generated in the primary ignition coil by rotation of the flywheel, and the current a flows, by which the condenser is charged. When the flywheel goes round further, direction of the current changes, and the current b flows, causing the current c and the current d flow to the power transistor and the transistor for signals for each. The condenser8is charged by the current d contrarily to the case 1). When the flywheel goes round further more, the current generated in the primary coil gets to its peak, and then begins decreasing. Then, voltage between C (Collector) and E (Emitter) of the transistor for signals becomes zero, and the transistor is turned OFF, while the current d changes to the current e and goes into the gate of the thyrister (SCR), thus turning the SCR ON. When the SCR is switched ON and the current b flows into the SCR (Current f), the current c flowing the power transistor is interrupted abraptly, generating high voltage by the current change in the secondary coil, thus giving sparks to the spark plug. ignition Coil Fig

34 1.1. ROBIN OIL SENSOR SYSTEM (FLOAT SYSTEM) In the EYOS, an oil sensor is available as a maker option FEATURES 1) The engine oil sensor detects the quantity of engine oil and automatically stops the engine, if it falls below the specified level, to prevent the engine from burning due to oil maintenance failure or for other reasons. If the oil shortage warning lamp is connected to the connecting terminal for it. the warning lamp is lit when the engine stops. 2) If the engine oilis short when the engine is started, the engine can not be started, even if the recoil starter is pulled. If the warning lamp is connected, the lamp is lit to indicate oil shortage. 3) As the power generated by the igniter is used, any special power supply unit is not necessary. 4) On-tatch stop is possible also by using the stop button, which is generally incorporated in the unit, based on a push button system. (Self-maintaining and automatic restoration circuits are incorporated in the unit.) 5) This system features the malfunction preventing structure depending on outer magnetic field BASIC PRINCIPLE This oil sensor system consists of a flywheei magneto, an igniter, an oil level controller, and an oil level sensor. As shown in Fig. 43, when the oil level is above the specified one, the lead switch contact is OFF, and the engine can run normally (sensor OFF condition). If the oil becomes short and position of the float in the sensor case goes down to the specified level shown in Fig. 44, the lead switch contact is turned ON by the magnetic field of the permanent magnet incorporated in the float (sensor ON condition). When the oil level sensor is turned ON, the current il generated by the counter-electromotive voltage VI in the primary ignition coil flows from the primary wire of the igniter via the delaying circuit of the oil level controller, both of which are shown in the block diagram. When the current ii generated by the counter electromotive voltage VI goes up to a certain level, the current il is loaded to the SCR gate from the delaying circuit via the self-maintaining circuit if V, is loaded. Then, the SCR is turned ON, thus starting operation of the warning lamp driving circuit, lgighting the warning lamp to indicate the oil shortage condition, and completely short-circuiting the regular electromotive voltage V, in the primary coil of the igniter for the igniter not to generate sparks. This condition is continued until the engine is stopped by the self-maintaining circuit. In normal stopping operation of the engine, the current i, generated by the regular electromotive voltage V, in the primary coil of the igniter is loaded, via the stop switch, to the self-maintaining circuit of the oil level controller. This current is loaded to the SCR gate via the self maintaining curcuit, and the SCR is turned ON. When the SCR is turned ON, the driving circuit of the warning lamp starts operating, thus lighting the warning lamp, and completely short-circuiting the regular electromotive voltage V, in the primary coil of the igniter for the igniter not to generate sparks. This condition is continued until the engine is stopped by the self-maintaining circuit. In restarting, the engine stopping operation is cancelled by automatically restoring mechanism, and the engine can be started normally

35 Permanent Magnet, Shield Case 7 [ F d Switch Oil Scraper Oil Level),!- Tightening Torque: 80-90kg-cm.ankcase Sensor OFF (Running Mode) Fig. 43 Sensor ON (Stop) Fig. 44 Fig

36 11-3 CHECKING PROCEDURE When the engine can not be started, supply oil up to the maximum oil level, and pull the recoil keeping the engine in the horizontal position. Engine oil is supplied up till the maximum level; but it doesn't start yet, please check the engine in the following manner. 1) Oil Level Sensor Checking (See Fig. 46.) Disconnect the sensor from the controller, and check with a tester continuity between the sensor lead wire (yellow) and the grounding wire of the engine. When there is no continuity under the condition that the oil has been supplied up to the specified level (about 280 cc), the oil level sensor is normal. If there is continuity, replace it with a new one. When there is continuity under the condition that the oil level is below the specified one (200 cc), the sensor is normal. If not, replace the sensor with a new one. Fig. 46 2) Oil Level Controller Checking (See Fig. 47) Disconnect the sensor from the controller (don't disconnect the stop button from the controller), and start operation of the stop switch after setting rpm of the engine at more than 1,200 rpm. (Don't continue depressing it, and restore it to the normal position soon.) Warning lamp is lit in a few seconds and the engine is stopped, the controller is normal. If the oil warning lamp is not lit and the engine is stopped, replace the warning lamp with a new one. If the engine does not stop in a few seconds (about 2 seconds), inner section of the controller is defected, so replace it with a new one. Controller Stop Switch Fig

37 11-4 PRECAUTIONS 1) The oil level sensor used in this controlling system has a float which can automatically detect the oil level according to the oil level change. However, if degraded oil, oil of improper grade, or oil with viscocity which is not appropriate for the periopheral temperature should be used, sometimes the float does not operate normally and fails in detecting the oil level. 2) Don t drop the oil level sensor and the oil level controller, nor add any physical impact to them. Don t pull the wire. 3) In removing the oil level sensor from or mounting it to the crankcase, be careful not to damage the O-ring. Don t disassemble the oil level sensor removed. In cleaning the oil level sensor, use the engine oil. If cleaned with gasoline or kerosene, the O-ring may swell. 4) Mount the oil level sensor under the condition that the crankcase has been fully cooled. Use a 21mm spanner for tightening the bolts. Tightening torque: kg-cm. (If a box spanner is used, the wire may be damaged.) Wire connection should be done as shown in the wiring diagram. Be careful in tightening or wiring not to give damages to the wire. 5) If the warning lamp is broken soon, it suggest the possibility of the warning lamp s capacity shortage. Standard Lamp : 6V - 0.6W Light emitting diode: 30 ma (ID) 11-5 WIRING Igniter Green r - E Oil Level m 3 Controller a.- - m 1 I m - m Z E T m 0 Oil LevelSensor Flywheel Oil Level g Oil Shortage Connecting Terminal Lamp Yellow I I 1 \ Crankcase Oil Shortage Warning Lamp #e 1ow - (Crankcase) Fig

38 12. TROUBLE SHOOTING The following three conditions must be satisfied for satisfactory engine start. 1. The cylinder filled with a proper fuel-air mixture. 2. An appropriate compression in the cylinder. 3. Good sparks at the correct time 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 high a back pressure due to a long exhaust pipe, justo say a few. The most common causes of engine troubles are given below: 12-1 STARTING DIFFICULTIES FUEL SYSTEM 1) No gasoline in the fuel tank; or the fuel cock is closed. 2) The carburetor is not choked enough, particularly when the engine is cold. 3) Water, dust or gum in the gasoline block flow of the fuel to the carburetor. 4) Inferior grade gasoline or poor quality gasoline is not gasfied 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, depending on cases, by lightly tapping the float chamber with the grip of a of 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 pull the recoil starter 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 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 non-operation. 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 compression stroke. 4) In correct Tappet Clearance If the correct compression is not obtained even after 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, and clean, remedy or replace the parts

39 ELECTRICAL SYSTEM Check the following for lack of sparks. 1) Leads of the ignition coil or spark plug 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 in contact with each other. 7) Incorrect spark timing. (Is the flywheel set in the correct position by the key?) 12-2 ENGINE MISFIRES 1) Incorrect spark plug electrode gap. Adjust it to anywhere between 0.6 and 0.7 mm. 2) Ignition cable worn and leaking. 3) Sparks weak. 4) Ignition wire connections loose. 5) Water in gasoline. 6) Insufficient compression 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 ca plugged. 5) Bearing parts seized due to lack of oil. 6) Magneto or ignition coil faulty ENGINE OVERHEAT 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 party misdirected causes loss of cooling efficiency. 6) Cylinder head cooling fins clogged up with dirt. 7) Engine operated in an ecnlosed space without fresh supply of 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

40 12-5 ENGINE KNOCKS 1) Low-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) Causes of engine overheat ENGINE BACKFIRES through CARBURETOR 1) Water or dirt in gasoline, or low-grade gasoline. 2) Intake valve stuck. 3) Valves overheated, or red-hot carbon particles in the combustion chamber. 4) Engine cold

41 13. INSTALLATfON 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 INSTALLING When mounting the engine, carefully examine its position, the method of connecting it to a load (machine), the foundation, and the mehtod of supporting the engine. When determining its mounting position, in particular, make sure that gasoline and 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 discharges VENT1 LATION Fresh air is necessary for cooling the engine and burning the fuel. In case where 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 he hot air used for engine cooling, and temperature rise of the load (machine). Take steps as necessary to keep the engine room temperature below 50 C even in the hottest period of the year. I 13-3 EXHAUST GAS DISCHARGE Exhaust gas in 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 increase in proportion to exhaust pipe length. Exhaust pipe: Less than 3 m long, pipe inside diameter 25 mm, Less than 5 m long, pipe inside diameter 30 mm POWER TRANSMISSION to DRIVEN MACHINES 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 load. * The driving pulley of the engine must be in line with the driven pulley of the load. * 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 thelike 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

42 13-5 WIRING Wire as shown in the wiring diagram below. u. T. c. I. Ignition Coil - cn 3 n 5 m P UJ Fig

43 14. CHECKS and CORRECTIONS After disassembling and cleaning the engine, check and repair, if necessary, according to the correction table. The correction table apolies whenever the engines are repaired. It is important for the servicemen to be familier with the contents of this table. Correct maintenance is recommended by observing the correction standards specified. The meanings of the terms used in the correction table are as follows: Correction Repair, adjustment or replacement of any engine parts. Correction Limit The limit on wear, damage or functional deterioration of engine parts beyond which normal engine performance cannot be expected without repairing such parts. Use Limit The limit beyond which parts can no longer be used in respect of performance or strength. Standard Dimensions The design dimensions of new parts minum tolerance. Correction Tolerance Tolerance on the dimensions of engine parts refinished or adjusted