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Subaru Robin Power Products 17 Automobile Parts User Manual

1. Oil consumption has been measured under following condition Good break in operation has been finished Oil 10W 30 Grade SE Load Continuous load 3600 rpm 79 STD Limit VALVE SPRING FREE LENGTH EX13 EX17 27 4 21 1 0787 27 VALVE SEAT ANGLE INTAKE AND EXHAUST Valve cutter angle a Valve contact width b EX13 Intake EX17 B 0 20 21 0 0787 EX27 0 0276 0 0394 b b a CHAIN LENGTH 263 1 266 0 10 3583 10 4726 160 16kgf lt F PES e 269 0 272 1 252525 2525 9 107120 281 7 284 9 BAAI 11 0906 11 2165 307 1 310 6 12 0906 12 2284 EX13 EX17 EX21 EX27 Compression pressure kd cm 500 rpm 3 5 4 0 4 0 4 0 Fuel consumption Continuous load 3600 rpm L Hr 1 2 1 6 1 9 2 6 Capacity L 0 6 1 0 Lubricant Efficacy mL 350 500 Consumption mL Hr 5 10 8 13 16 2 TIGHTENING TORQUE Tightening Torque ITEM N m kgf cm ft Ib Re use 25 0 27 0 250 270 19 5 M8 x 68 flange bolt When replace to new Cylinder head bolts cylinder head and 28 0 30 0 280 300 20 3 21 7 flange bolts 8 x 35 flange bolt 17 0 19 0 170 190 12 3 13 7 Connecting rod
2. 21 SPEED CONTROL LEVER BRACKET AND BAFFLE Mount the speed control lever and bracket baffle 2 head and baffle 3 on the crankcase NOTE The baffle 3 is used for Model EX21 only 22 CARBURETOR a Replace the gasket of insulator with a new one and mount the insulator on the cylinder head intake side b Mount the carburetor M6 x 12 BOLT 2 pcs SPEED CONTROL LEVER and BRACKET 1 200 0 M6 x 12 BOLT 1 pce BAFFLE 3 EX21 ONLY M5 TAPPING BOLT 2 pcs Fig 5 54 d 23 GOVERNOR LEVER a Pass the governor rod through the rod spring then connect to the throttle lever of the carburetor b Attach the governor rod and rod spring to the governor lever then mount the governor lever on the governor shaft Do not adjust the bolt on the governor lever yet c Connect the governor lever and the speed control lever with the governor spring NOTE See page 42 for details on the adjustment method after mounting air cleaner base Variation of the governor spring The dimensions of the governor spring are different each other according to the Hz The governor spring for the standard engine is same as that for the engine to be connected to the 60Hz generator Discrimination according to the dimensions EX13 17 50Hz EX21 27 50Hz C gt WU gt Le P bs Color Gold Speed side Color Gold Governor lever side
3. CAMSHAFT Fig 5 19 CHAIN 22 CHAIN SPRING TENSIONER M6 x 12 BOLT 1 pc Bolt used to prevent the pin camshaft from coming out TENSIONER PIN TENSIONER Fig 5 17 _ 25 Parts to remove Remarks and procedures Fasteners Cylinder head 1 Remove the cylinder head from the 12 mm box spanner Chain guide crankcase M8 x 68mm 4 pcs 23 2 Remove the cylinder head gasket from the M8 x 35mm 1 pc cylinder head Take care not to lose the pipe knocks 3 Remove the chain guide from the top side of the crankcase If the chain guide is removed from the inner side of the crankcase it might be damaged 24 Intake and exhaust 1 Remove the collet valve from the valves spring retainer See Fig 5 21 2 Remove the intake valve and the exhaust valve COLLET VALVE SPRING RETAINER PIPE KNOCK VALVE SPRING GASKET 4 c VALVE BN M8 x 68 BOLT 4 pcs EXHAUST Ne N A VALVE SPRING WALA Ve VALVE Y 7 4 VALVE STEM SEAL CYLINDER HEAD SPRING RETAINER M8 x 35 BOLT 1 pc This bolt is same as the main bearing cover bolt Fig 5 20 Remarks procedures Fasteners 25 Connecting rod and piston 1 Scrape off any carbon from the cylinder and th
4. EX13 17 21 27 60Hz STD 2 P ls Color Silver GOVERNOR ROD and ROD SPRING GOVERNOR VERNOR SPRIN LEVER m 2 Long N length side Short length side SPEED CONTROL LEVER and BRACKET o 24 AIR BASE Insert the breather pipe into the rocker cover and then mount the air cleaner base M6 flange nut 2 pcs M6 x 20 mm flange bolt 1 pc Tightening torque 6 0 80 60 80 kgf cm 4 3 5 8 fil Ib m Governor system adjustment method M6 x 20 FLANGE BOLT 1 pc M6 FLANGE NUT 2 pcs Fig 5 57 The governor unit is a centrifugal flyweight type and is installed on the governor gear Since it automatically adjusts the throttle valve of the carburetor by means of a link mechanism it is possible to maintain a constant engine speed even with load variations 1 Turn the speed control lever to the full speed position making sure that the carburetor throttle valve is fully open 2 Hold the top of the governor shaft with the plier and turning it clockwise as far as it will go Tighten the bolt on the governor lever Tightening torque 8 0 10 0 N m 80 100 cm 5 8 7 2 fil Ib 42 GOVERNOR LEVER GOVERNOR ROD and ROD SPRING GOVERNOR SPRING GOVERNOR SHAFT 25 MUFFLER M6 x 10 f TAPPING BOLT 2
5. EX21D 15 0 14 0 13 0 120 00 kgf 1 5 1 4 1 3 1 2 W TORQU OUTPUT HP 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 EX27D MAXIMUM TORQUE A RECOMMENDED HORSEPOWER 2400 2800 3200 3600 REVOLUTION gt r p m 6 EEB 4000 kgf 1 9 1 8 1 7 1 6 1 5 3 TORQUE gt 3 FEATURES 3 1 EXTREMELY SILENT SOFT QUALITY EX engines are 2dBA quieter and softer in tone than other engines in the same class This quiet and soft tone is achieved by reduction in mechanical noise realized by employing sophisticated system Employment of an optimized capacity Rigid Muffler 3 2 EXTREMELY EASY START NO KICK BACK Reliable Starting and Less Pulling Force are achieved by Sophisticated Mechanical Compression Release System as well as newly designed Combustion Chamber EX engines start instantly even at minus 10 without any perceptible kick back 3 3 EXTREMELY EASY MAINTENANCE Extreme ease of maintenance is realized by High Parts Commonality simplifies maintenance amp lowers repair cost due to fewer parts for service More than 90 of component parts are in common between more than two models in such as Muffler Intake and Exhaust Valves Valve Springs etc Furthermore more than 50 of component parts are in common among E
6. 57 19 RECOIL STARTER WR e 61 14 INSTALLATION gt 66 15 TROUBLESHOOTING u sas wee tooo en wee ese asas ah ea 68 16 STANDARD REPAIR TABLES U 74 15 1 STANDARD DIMENSIONS AND LIMITS OF USE 74 15 2 TIG TENING TORQUE Fc c 80 CONTENTS 17 MAINTENANCE AND S ORAGE bad sous u uu u J 81 1 SPECIFICATIONS Model EX13D EX17D EX21D EX27D Air Cooled 4 Slant Single Cylinder yp Horizontal P T O Shaft OHC Gasoline Engine Bore amp Strok mm 58 x 48 67 x 48 67 x 60 75 60 Mid ciis ds 2 28 1 89 2 64 1 89 2 64 2 36 2 95 2 36 Piston Displacement mi bee 169 zn os p cu in 7 69 10 31 12 87 16 17 Compression Ratio 8 5 8 3 1 9 2 6 3000 2 6 3 5 3000 3 2 4 4 3000 0 Continous Calpe KW HP rpm 2 208 0 8600 2 9 4 0 3600 37 5 0 3600 0 Maximum Output kW HP rp m 3 2 4 3 4000 4 2 5 7 4000 5 1 7 0 4000 0 8 1 2500 11 3 2500 13 9 2500 18 6 2500 Maximum Torque m r p m 0 83 2500 1 15 2500 1 41 2500 1 9 2500 f Ib p m 6 01 2500 8 34 2500 10 26 2500 13 74 2500 Direction of Rotation Counterclockwise as viewed from the P T O shaft side Valve Arrangement Overhead cam system Cooling
7. 1 Mount the muffler and the gasket on the cylinder head GASKET Attention to the wrong side and right side MUFFLER SIDE RIGHT SIDE M6x8 FRANGE BOLT 1 pc M8 NUT 2 pcs CYLINDER SIDE WRONG SIDE MUFFLER utmost care not to cut your SS hand with the muffler gasket M8 X12 mm bolt 1 pc M8 nut 2 pcs M8 x 12 BOLT 1 pc Tightening torque GASKET gt iu Hm Attention to the wrong a AA side and right side 2 Mount the muffler cover on the muffler M6 X 8 mm flange bolt 1 pc M6 X 10 mm tapping bolt 2 pcs NOTE Be sure to remove any tape or cloth used Fig 5 59a to cover the exhaust port when the engine 4 was disassembled 26 FUELTANK 1 Mount the fuel strainer to the fuel tank FUEL Tightening torque for fuel strainer STRAINER 3 0 4 0 N m FUEL PIPE 30 40 kgf cm 1 Cafe gt 2 2 2 9 fll lb Connect the fuel pipe and fix it with a clamp Model EX13 EX17 EX21 EX27 M6 x 25 BOLT 1pc EET 8 13 17 25 uel pipe leng 8 x 25 BOLT 2pcs mmn 145 5 7 150 5 9 155 6 1 195 7 7 Z f 27 V NOTE Make sure the fuel pipe is located on the boss as shown in the illustration in order to prevent Fig 5 59b the pipe from attaching to the flywheel In case the pipe is routed improperly the pipe might be hit
8. 1 Drain the engine oill 1 Remove a drain plug M14x12mm located on both sides of the case Take care not to lose the gaskets 2 To discharge oil quickly remove the oil guage 14 mm spanner OIL GAUGE N DRAIN PLUG 45 Parts to remove Remarks and procedures Fasteners Air cleaner cover Remove the air cleaner cover 2 Air cleaner Remove the element and remove the air 10 mm box spanner cleaner while pulling the breather pipe away 6 nut 2 pcs 3 from the rocker cover M6 x 20 1 pc STD TYPE DUAL ELEMENT TYPE Ce STEP 3 e STEP 3 AIR COVER gt AIR CLEANER ELEMENT 2 URETHAN FOAM PAPER URETHANE FOAM M6 x 20 FLANGE BOLT 1 pc AIR CLEANER COVER M6 FLANGE BREATHER NUT 2 pcs Parts to remove Remarks and procedures Fasteners Stop switch Disconnect the wire and remove the stop switch from the blower housing Recoil starter Remove the recoil starter from the blower 10 mm box spanner housing M6 x 8mm 4 pcs Blower housing 1 Remove the blower housing from the 10 mm box spanner Baffle 2 head crankcase M6 x 12mm 4 pcs Baffle 3 2 Remove the baffle 2 head and baffle 3 10 mm box spanner or spanner M6 x 12mm 2 pcs Baffle 2 head 5 tapping bolt 2 pcs Baffle 3
9. Model EX13 17 21 and 27D has a smooth advanced ignition timing system to improve starting performance IGNITION COIL For further details refer to page 48 section FLYWHEEL 7 MAGNETO Fig 4 11 10 4 14 CARBURETOR engine is equipped with horizontal draft carburetor The carburetor setting is calibrated after careful testing for optimum all round performance including starting acceleration fuel consumption output power characteristics Special attention is also paid to the general purpose use of the engine For further information refer to page 57 section 11 4 15 AIR CLEANER The engine uses an air cleaner that is quieter than conventional ones A semi wet urethane foam element is used in the STD air cleaner Dual element air cleaner with a primary element of dry type sponge and secondary element of dry type paper and other types are also provided as special options 4 16 BALANCER PROVIDED ONLY IN MODEL EX27D Unbalanced inertia force is cancelled by the balancer which rotates at the same speed as the crankshaft to effectively reduce vibration 4 17 DECOMPRESSION SYSTEM The automatic decompression system is mounted on the camshaft It opens the exhaust valve before the compression top thereby alleviating the compression pressure and reducing the force required to pull the recoil starter During engine operation the decompression system is overpower
10. 1 3575 1 3524 i EX1 Journal outer diameter E 27 988 27 997 1 1019 1 1022 D1 21 29 988 29 997 EX27 1 1806 1 1810 D1 E E 24 988 24 997 Of jJ D2 EX2 0 9838 0 9841 EX27 29 988 29 997 1 1806 1 1810 77 Unit mm in ITEM STD Limit CAMSHAFT Cam peak height intake and exhaust EX Cam peak EX17 29 028 29 128 28 98 height EX21 1 1428 1 1468 1 1409 EX27 Cam inner zs diameter EX17 9 0 9 036 9 05 EX21 0 3543 0 3557 0 3563 EX27 Cam sprocket inner diameter Pin cam sprocket outer diameter Pin outer 2018 Ds Da diameter EX17 8 953 8 975 8 95 oy f t Da 04 EX21 0 3525 0 3533 0 3524 27 I INTAKE EXHAUST VALVES EX13 Valve stem outer diameter EX17 5 440 5 455 5 35 21 0 2142 0 2148 0 2106 EX27 EX13 EX17 5 426 5 444 5 35 Exhaust 0 2136 0 2143 0 2106 27 Clearance between valve stem and EX13 valve guide 17 0 045 0 078 0 3 a EX21 0 0018 0 0031 0 0118 EX27 EX13 EX17 0 056 0 092 0 3 Exhaust Exa 0 0022 0 0036 0 0118 EX27 Valve clearance in cold state EX13 EX17 0 12 0 15 intake EX21 0 0047 0 0059 EX27 EX13 EX17 0 12 0 15 21 0 0047 0 0059 27 78 Unit mm
11. Be sure to keep the engine room temperature below 50 all year round and to prevent the accumulation of hot air in the engine room 14 3 EXHAUST EQUIPMENT Exhaust gas is noxious When operating the engine indoors make sure that exhaust gases are discharged outdoors However if the exhaust pipe is long resistance increases and this lowers engine output Therefore the longer the exhaust pipe the larger its inner diameter should be Exhaust pipe length Less than 3 m Pipe inner diameter 30mm Exhaust pipe length 3 5m Pipe inner diameter 33mm The ideal solution is forced exhaustion outdoors by installing a blower on the exhaust pipe Install a safety cover on the exhaust pipe muffler and other related parts 14 4 FUEL SYSTEM If the fuel tank is detached from the engine the height from the bottom of the fuel tank to the fuel joint of the carburetor should be between 5 cm and 50 cm When using a fuel pump the bottom of the fuel tank can be up to 20 cm below the carburetor Position the fuel tank carefully because when it is low fuel is not fed to the carburetor and when it is high it can cause an overflow in the carburetor When piping the fuel the hose should be as short as possible and attention should be paid to heat transmission size bending leakage at hose joints and so on Care should also be taken to prevent air lock and vapor lock 66 14 5 POWER TRANSMISSION DRIVE MACHINES 14 5 1 BELT DRIVE Note th
12. 1 pc Parts to remove Remarks and procedures Fasteners Baffle 1 case Remove the baffle 1 case M6 x 12mm 1 pc Models 13 17 and 21 16 M8 x 12mm 1 pc Model EX27 Charge coil option Remove the charge coil box spanner For EX27 remove the wire clamp together M6 x 20mm 2 pcs 17 Screwdriver Spark plug Remove the spark plug from the cylinder head 21 mm plug wrench 18 BAFFLE 1 CASE M6 x 12 FLANGE BOLT 1 pc EX13 17 21 8 x 12 FLANGE BOLT 1 pc EX27 For the model without electric starter gt SPACER BOLT M6 x 400 W x x mow NA 6 x 250 asw x Pow x M6x40L mow NA Ex 19 NA MexzoL w NA M6x30L NA M6 lt 25L Fig 5 12 CHARGE VIEW EX27 only 22 Parts to remove Remarks and procedures Fasteners Rocker cover 1 Remove the rocker cover from the 10 mm box spanner 19 cylinder head M6 x 12mm 4 pcs 2 Remove the gasket rocker cover Rocker arm Remove the pin rocker arm and the rocker 20 arm from the cylinder head at the compression top dead center See Fig 5 14b EXHAUST VALVE SIDE The position of compression top dead center ROCKER ARM INTAKE VALVE SIDE Fig 5 14a Fig 5 14b ROCKER ARM
13. 1215 to the surface of the crankcase To avoid damaging the oil seal lip wrap the crankshaft key way portion with polyvinyl tape before mounting the main bearing cover NOTE Be careful that the lever portion of governor shaft does not face the main bearing cover Tightening torque 17 0 18 0 N m 170 180 kgf 12 3 13 0 fif Ib GOVERNOR SHAFT CRANKSHAFT M8 x 35 BOLT 6 pes Sy J EX13 17 21 M8 x 35 BOLT 7 pcs EX27 SEALANT Three bond 1215 MAIN BEARING COVER 36 14 Pass the pin rocker arm through the rocker arm and mount them on the cylinder head NOTE 1 Conduct this job at the compression top dead center The position of two punch marks on cam sprocket is in parallel with the cylinder head surface at a time NOTE 2 Make sure that the piston is at the compression top dead center by checking mutual position between the flywheel and the ignition coil or by checking that the key way is at the top See each Fig 5 46 15 VALVE CLEARANCE ADJUSTMENT Temporarily fit the flywheel Rotate the crankshaft up to the compression top dead center and insert the thickness gauge between the valve and the adjusting screw of rocker arm to measure the clearance Adjustment method Loosen the nut on the adjustment screw and turn the screw to adjust the valve clearance When the valve clearance is correct tighten the nut Valve clearance when the engine is
14. 5 ftg lb flange bolt 4 pcs 17 0 19 0 N m 28 0 30 0 f 170 190 cm 280 300 an When replace to new cylinder 12 3 13 7 ft Ib 20 3 21 7 ft b head and flange bolts M8 x 35mm 0 u flange bolt 1 pc Tighten the cylinder head bolts in diagonal order 1 Re use Oil the screw thread e Tighten all bolts 5pcs by 18 1 primary and then tighten longer ones M8 x 68mm flange bolt 4pcs by 26 1 N m 2 When replace to new cylinder head and flange bolts Oil the screw thread e Tighten all bolts 5pcs by 18 1 primary and then tighten longer ones M8 x 68mm flange bolt 4pcs by 29 1 N m CYLINDER HEAD M8 x 35 BOLT 1 pc Fig 5 40 E wn 9 SETTING THE TIMING CHAIN a Align the timing mark on the crankshaft sprocket with the mark plate of the timing chain b Align the timing mark on the crankshaft sprocket with the mark plate of the opposite end of the timing chain Model EX13 EX17 21 27 Number of oval steel link 86 88 92 100 CHAIN GUIDE FITTING POSITION MARK PLATE Model EX1 3 3X The mark plate does not have a camshaft side or crankshaft sprocket side The position of top dead center TIMING MARK sprocket side TIMING MARK CAMSHAFT SPROCKET MARK PLATE CHAIN GUIDE FITTING POSITION MARK PLATE Model EX17 27 mark plate does not ha
15. Leakage from carburetor gasket Retighten replace gasket 8 Insufficient tightening of spark plug Retighten 68 Problem possible cause Remedy Poor output 1 Insufficient compression 2 Ignition system problems 3 Fuel system malfunction 1 Loosen spark plug Retighten replace gasket 2 Leakage from cylinder head gasket Retighten replace gasket Replace 3 Piston ring seizure or wear 4 Piston or cylinder wear Repair or replace 5 Incorrect valve and seat contact Repair or replace Repair or replace 6 Valve stem seizure 7 Improper valve clearance Adjust 1 Faulty spark plug Replace 2 Faulty ignition coil Replace 3 Improper air gap between ignition coil and Adjust flywheel 4 Demagnetization flywheel magneto Replace 1 Carburetor clogged Overhaul clean 2 Fuel strainer and or hose clogged Clean or replace 3 Air in fuel lines Check and retighten joints 4 Poor quality gasoline or water in gasoline Replace 4 Low air intake volume 1 Air cleaner clogged Clean or replace 2 Throttle valve malfunction Repair or replace guide 1 Engine 1 Cooling air flow obstructed at inlet or cylinder Clean baffle portion 2 Poor quality engine Replace TEE Check and adjust 3 Lean fuel air mixture carburetor 4 Excessive ba
16. M6 x 8 BOLT 4 pcs M6 x 12 BOLT 4 pcs M4 TAPPING SCREW 2 pcs STOP SWITCH BLOWER HOUSING BAFFLE 2 HEAD BAFFLE 3 EX21 ONLY M6 x 12 BOLT 1 pc M5 TAPPING BOLT 2 pcs Fig 5 4 7 M8 x 12 FUEL DRAIN X Seal the exhaust port with Parts to remove Remarks and procedures Fasteners Fuel tank 1 Drain fuel from the carburetor drain 10 12 mm spanner or box 2 Remove the fuel tank mounting nuts wrench and bolts from the crankcase M6 nut 2 pcs 3 Disconnect the fuel pipe from the carburetor Models EX13 17 and 21 7 See Fig 5 6 nut 2 pcs Model EX 27 4 Remove the fuel tank from the crankcase M6 x 25mm 1 pc Models EX 13 17 and 21 x 25mm 2 pcs Model EX27 Muffler and Muffler cover 1 Remove the muffler cover from the 12mm box spanner muffler 10mm box spanner or 2 Remove the muffler from the cylinder spanner head Take care not to lose the gasket M6 tapping bolt 2 pcs 8 Take care not to cut your hand with the M6 x 8mm 1 pc muffler gasket M8 nut 2 pcs Seal the exhaust port with adhesive M8 x 12mm 1 pc tape or plug it with cloth to prevent nuts and other objects from falling inside i TAPPING BOLT 2 pes w M6x8 FLANGE BOLT 1 pc M8 NUT 2 pcs M6 x 25 BOLT 1 pe M6 NUT 2 pcs 17 21 M8 NUT 2 pcs EX27 MUFFLER GASKET
17. System Forced air cooling system Lubrication System Splash lubrication system Lubricant Automobile engine oil Grade SE or higher SG SH or SJ in recomended SAE 10W 30 Under ordinary atmospheric temperatures SAE 5W 30 In cold areas Capacity of Lubricant L 0 6 1 0 Carburetor Horizontal draft Float type Fuel Automobile unleaded gasoline Fuel Consumption Rate EUM 367 270 at continuous rated output Fuel Supply System Gravity type Fuel Tank Capacity L 2 7 3 6 6 1 Ignition System Transistorized magneto Spark Plug NGK BR 6HS CHAMPION RL86C Charging Capacity _ Option V A 12 1A 3A 16 7A Option Starting System Recoil starter Recoil starter Electric starter Option Governor System Centrifugal flyweight system kg 14 15 16 21 6 80 87 33 08 35 28 46 31 Dimensions L x W x mm 297 x 341x 318 304 x 354 x 335 311x 366 x 335 351 x 420 x 410 11 7x13 4x12 5 12 0x13 9x13 2 12 2x14 4x13 2 13 8x16 5x16 1 Specifications are subject to change without notice 2 PERFORMANCE 2 1 MAXIMUM OUTPUT The Maximum output is the output of an engine with its throttle valve fully opened and considering that all the moving parts are properly broken in A new engine may not produce full maximum output while its moving parts are still not broken in NOTE Power curves shown in the f
18. and check item Description Remedy 1 Checking of Check S terminal and B terminal 1 When no voltage is applied to the S continuity of for deformation looseness terminal and B terminal check wiring rusting or dust sticking continuity of the terminals and key Carefully check inserting switch and repair or replace if KEY SWITCH method of the S terminal If not abnormal set the key switch to START position while cranking no ignition of engine and check if voltage is applied necessary 2 If voltage is applied to the S terminal and B terminal go to 2 Battery checking to the S terminal and B terminal of starter motor 2 Battery checking Check battery voltage and specific 1 Charge or change the battery when gravity of battery fluid voltage is lower than 12 4V or specific Voltage gravity is lower than 1 22 at 20 Normal value 12 4 to 12 8V Limit charging required 12 4V 2 If the wiring and battery are normal GRAVITY METER remove the starter and go to 43 SI owl Checking of pinion operation Staring limit 12V at 200C ZR P Specific gravity Normal value 1 22 to 1 29 Limit Charging required DEI BATTERY 1 22 or lower gt Service life f m yo Variance in specific gravity among cell 0 04 or more 1 Starter does not run or only click sound is heard 3 Checking of pinion operation Check if the pinion operates or sound of magnetic switch c
19. cold Intake valve side 0 12299 mm 0 0047 72972 in top dead center The position of compression ROCKER ARM EXHAUST VALVE SIDE PIN ROCKER ARM ROCKER ARM INTAKE VALVE SIDE Exhaust valve side Nlm 5 0 7 0 kgf 70 50 orque 3 6 5 1 ft b NOTE After adjusting the valve clearances rotate the crankshaft and check again that the intake and exhaust valve clearance are correct 7 SD ADJUSTMENT SCREW lt 6 ROCKER ARM Ke 6 EXHAUST WU VALVE SIDE NUN 4 NN gt T Gu S OS NC Q ROCKER ARM INTAKE VALVE SIDE Fig 5 47 16 ROCKER COVER SPARK PLUG 1 AV A GASKET ROCKER COVER ROCKER VER we x 12 BOLT 4 pcs the rocker cover M6 x 12mm flange bolt 4 pcs Tightening torque 5 0 7 0 Njm 50 70 kgf cm 3 6 5 1 0 17 SPARK PLUG Remove any carbon deposits from the spark plug and inspect the electrode for damage before mounting Replace with a new one if necessary Spark plug NGK BR 6HS Fig 5 48 or CHAMPION RL86C Tightening torque Electrode gap 0 6 mm 0 7 mm 18 BAFFLE 1 CASE New spark plug Re tightening torque 12 0 15 0 120 150 kgf cm 8 7 10 8 ft Ib 23 0 27 0 N m 230 270 kgf
20. cylinder head connect the spark plug with the plug cap and ground it on the cylinder head or any other metallic part of the engine The gap between the electrodes of the spark plug should be between 0 6 mm and 0 7 mm Rotate the engine by pulling the recoil starter and check the spark plug gap for sparking If the spark plug is sparking check the intensity of the spark Before checking the spark plug disconnect the primary wire from the connector G Next disconnect the spark plug from the plug cap and check the end of the high tension cable for sparking 48 7 3 IGNITION SYSTEM EX13 17 21 7 3 1 TYPE OF IGNITION SYSTEM EX13 17 and EX21 have the T I C Transister Igniter Circuit pointless ignition system As optional parts these ignition system may be implemented with lamp coil charge coil and excitor coil Resister LowSpeed Ignition Timing Control Circuit Power Transistor Primary Coil Automatic Advancing Control Circuit Signal Transistor A Signal Transistor B Ignition Coil Spark Plug Fig 7 1 ELECTRONIC ADVANCING FLYWHEEL 7 3 2 BASIC THEORY MAGNETO SYSTEM 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 STE
21. free movement of the connecting rod by turning the crankshaft slowly 6 INTAKE AND EXHAUST VALVES Take the following points into account when mounting the intake and exhaust valves on the cylinder head NOTE 1 Replace the valve with a new one if it shows signs of wear Refer to the STANDARD REPAIR TABLES on page 78 and 79 NOTE 2 Carefully scrape off any carbon deposits on the combustion chamber Apply oil to the valve stems before mounting the intake and exhaust valves Insert the valves in the cylinder head and place it on a level workbench Next mount the valve springs the spring retainers and collet valves Mount the stem seal on the intake valve guide INTAKE VALVE 32 ALIGNMENT ALIGNMENT MARKS MARKS Fig 5 38a COLLET VALVE SPRING RETAINER VALVE SPRING NO gt CYLINDER HEAD De STEM SEAL COLLET VALVE VALVE SPRING SPRING RETAINER Fig 5 38b 7 GUIDE GUIDE Mount the chain guide to the crankcase Model EX21 mounting position Models EX13 17 and 27 mounting positions ad 7 Fig 5 39a Fig 5 39b 8 CYLINDER HEAD Inspect and repair any scratches on mounting surface and replace head gasket to new one before installing Tightening Torque 15 step 2 step Cylinder head bolts Remarks 25 0 27 0 250 270 kgf cm Re use M8 x 68mm 18 1 19
22. glasses NOTE Put on the protective glasses prior to start disassembly 13 1 1 DISASSEMBLY PROCEDURE 1 Release the reel spring power 1 Hold the starter knob and pull out the starter rope 2 Pull out the rope fully and align the rope knot in the reel with the rope guide 3 Hold the reel down firmly with both thumbs taking care not to allow it to spring back Fig 12 1 4 Remove the knot from the reel untie the knot and pull the rope out toward the starter knob Note This procedure requires 2 people 5 While controlling the reel with the thumbs slowly wind it back as far as it will go NOTE When the rope is pulled out to its full length the force stored in the spring reaches its maximum Be careful not to drop it or release your grip on it suddenly 2 Remove the components Fig 13 2 1 Grip the case and loosen the set screw SET SCREW 2 Take out the set screw the ratchet guide RATCHET the friction spring and the ratchet in that CA GUIDE order O FRICTION 3 Remove the reel Fig 13 2 SPRING 1 Hold down the reel gently to keep it from escaping from its case and rotate it slowly back and forth by quarter turns until it moves smoothly RATCHET 2 Lift the reel up little by little and take it out of Beer the case 3 If the spring is about to pop out of the reel repeat steps 3 1 and 3 2 STARTER CASE
23. that has been completely overhauled by being fitted with a new piston rings valves and connecting rod should be thoroughly RUN IN before being put back into service Good bearing surfaces and running clearances between the various parts can only be established by operating the engine under reduced speed and loads for a short period of time While the engine is being tested check for oil leaks Make final carburetor adjustment and regulate the engine operating speed 2E 4E JE EZ Step 1 No Load 2500 10 2 Load 3000 10min 3 Load 3600 10min 4 1 5 HP 2 HP 2 5 HP 35 HP 3600 30 5 3 HP 4 HP 5 HP 7 HP 3600 r p m 30 min 46 6 Using engine of the correct grade viscosity greatly lengthens engine life improves performance Too much or too little oil can also result in serious problems including engine seizure 6 1 CLASSIFICATION BY OIL GRADE API American Petroleum Institute Grades suited for Robin Engine SE or higher SG SH or SJ in recomended 6 2 CLASSIFICATION BY OIL VISCOSITY SAE Society of Automotive Engineers 10W Single grade u 10W 40 a Ambient 1 10 0 10 20 30 6 temperature 4 14 32 50 68 86 104F sure to use automobile engine oil of the visc
24. 27 Intake exhaust valve seat contact width EX13 Intake EX17 0 7 1 0 Exhaust 21 0 0276 0 0394 7 27 EX13 Intake EX17 5 500 5 518 Exhaust EX21 0 2165 0 2172 7 7 Rocker arm outer diameter Di D2 i EX13 2 17 5 970 5 980 5 9 i D1 De EX21 0 235 0 235 0 232 EX27 Rocker arm pin support inner diameter Ds D4 a n i Support EX13 N inner EX17 6 00 6 018 6 05 diameter EX21 0 236 0 237 0 238 Ds D4 EX27 74 Unit mm ITEM STD Limit CYLINDER EX13 58 000 58 019 Inner diameter 2 2835 2 2842 To be rebored when EX17 67 000 67 019 the difference between Standard EX21 2 6378 2 6385 max and min of E diameter reached to 75 000 75 019 04 0 004 EX27 2 9528 2 9535 58 250 58 269 EXIS 2 2933 2 2941 First 7 67 250 9 reboring 2 6476 2 6484 pnto 75 250 75 269 EX27 2 9626 2 9633 58 500 58 519 EX13 2 3031 2 3039 Second EX17 67 500 67 519 Ditto reboring EX21 2 6575 2 6582 75 500 75 519 2 9724 2 9732 EX13 Roundness after reboring EX17 Less than 0 01 EX21 0 0004 EX27 EX13 17 Less than 0 015 Cylindricity after reboring 21 0 0006 27 5 EX13 57 980 58 000 57 89 Outer diameter at skirt in thrust 2 2827 2 2835 2 2791 direction Standard 66 960 67 000
25. 306 LA406 Black OA f B Magnetic switch Key switch 066 00003 30 Electric starter Fig 8 2 Si 8 3 MODEL WITH ELECTRIC STARTER Model 27 Spark plug Black lt gt 4 Black Magneto Ignition coil Key switch Charge coil Key switch 066 00003 30 8 4 MODEL WITH OIL SENSOR To LED Lamp Yellow lt Battery 12V24AH Orange Orange l Body earth Oil sensor as option Yellow Red Black Oil sensor Black White control unit LA106 Black 5 0 stop switch Fig 8 4 9 ELECTRIC STARTER 9 1 SPECIFICATIONS EX 17 21 Models EX17 21 Model EX27 Pinion gear Voltage V 12 Power kW 0 6 0 6 3 Weight kg 1 6 3 4 I EX 27 i u _ u E K Y 157 8 1 GEAR Fig 9 1 9 2 OPERATING PRINCIPLES The battery is connected to the 6 or 8 mm diameter terminal of the magnetic switch The figure below shows the state when the starter is ON M g
26. 66 88 21 2 6362 2 6378 2 6331 74 980 75 000 74 89 EX27 2 9520 2 9527 2 9484 z 58 230 58 250 58 14 2 2925 2 2933 2 2890 Oversize EX17 67 210 67 250 67 13 gt lt 0 25 EX21 2 6461 2 6476 2 6429 75 230 75 250 75 14 ERAT 2 9618 2 9626 2 9583 58 480 58 500 58 39 ERIS 2 3024 2 3032 2 2988 Oversize EX17 67 460 67 500 67 38 0 50 EX21 2 6559 2 6575 2 6528 75 480 75 500 75 39 EX27 2 9717 2 9724 2 9681 75 Unit mm ITEM STD Limit PISTON EX13 Ring groove side clearance Top EX17 0 035 0 080 0 15 Second EX21 0 0014 0 0031 0 0059 EX27 0 02 0 075 Enis 0 0008 0 0031 Oil ring EX17 0 01 0 065 0 15 Coil exp 21 0 0004 0 0026 0 0059 0 01 0 065 0 0004 0 0026 0 060 0 165 0 0024 0 0065 Oil ring EX17 0 0300 0 185 three piece 21 0 0012 0 0073 0 0100 0 205 0 0004 0 0081 Piston hole EX13 12 991 13 009 13 035 0 5115 0 5122 0 5132 EX17 15 991 16 009 16 035 EX21 0 6296 0 6303 0 6313 17 991 18 009 18 035 Exar 0 7083 0 7090 0 7224 Piston pin outer diameter EX13 12 992 13 000 12 960 0 5115 0 5118 0 5102 9 7 15 992 16 000 15 960 21 0 6296 0 6299 0 6283 17 992 18 000 17 960 ENT 0 7083 0 7087 0 7071 Clearance between piston an
27. COVER EXHAUST VALVE In TAIL SCREEN FUELTANK 4 A or DEFLECTOR a OPTION OLI d LH GOVERNOR SPARK GEAR ARRESTER 59 BN 55 ROCKER SWITCH mee SE ARM 0 2 0 0 CAMSHAFT O 62 o O VALVE aa CHAIN PISTON PIN PISTON RING O STARTING MOTOR TENSIONER N 3s OIL GAUGE FILLER PLUG OO OIL DRAIN PLUG CONNECTING ROD CRANKCASE CRANKSHAFT OIL SENSOR OPTION Fig 4 17 _ 13 5 DISASSEMBLY AND REASSEMBLY 5 1 PREPARATIONS AND PRECAUTIONS 1 When disassembling the engine memorize the location of each part so that you can reassemble the engine correctly If necessary attach identification tags with the required assembly information to the parts 2 Store groups of parts in separate boxes This will make reassembly easier 3 To prevent parts from being mislaid keep each group provisionally assembled after removing the parts from the engine 4 Handle the disassembled parts with the utmost care Clean them with cleaning oil if necessary b Use the correct tools in the correct way when disassembling and reassembling the engine 5 2 SPECIAL TOOLS Tool name Use Commercially available product Flywheel puller For pulling off the flywheel FLYWHEEL PULLER Fig 5 1 14 5 3 DISASSEMBLY PROCEDURE Step Parts to remove Remarks and procedures Fasteners
28. EXHAUST ROCKER ARM ROCKER ARM INTAKE VALVE SIDE CLOSE UP A GASKET ROCKER COVER STEP 19 ROCKER COVER M6 x 12 BOLT 4 Fig 5 13 _ 23 Parts to remove Remarks and procedures Fasteners 21 Main bearing cover 1 Remove the flange bolts of main bearing 12 mm box spanner cover from the crankcase M8 x 35mm 6 pcs Remove the main bearing cover while Models EX13 17 and 21 tapping gently around the cover using M8 x 35mm 7 pcs a plastic hammer or similar tool Model EX27 See Fig 5 16 Be careful not to damage the oil gauge or oil seal or not to lose the pipe knocks 8 x 35mm 6 pcs MODELS EX13 17 AND 21 M8 x 35mm 7 pcs MODEL EX27 STEP 21 MAIN BEARING COVER Fig 5 15 24 Parts to remove Remarks and procedures Fasteners Tensioner Camshaft 1 Remove the tensioner See Fig 5 18a M10 box spanner or spanner Do not lose the pin tensioner M6 x 12mm 1 pc 2 Remove the retaining bolt of pin camshaft from the cylinder head See Fig 5 18b 22 3 Remove the pin camshaft taking care not to scratch the O ring 4 Remove the chain from the camshaft sprocket and then take out the camshaft See Fig 5 19 5 Remove the chain from the crankshaft Bolt used to prevent the PIN TENSIONER I pin camshaft from coming out Fig 5 18a Fig 5 18b
29. It has two faces adhesive tape or plug it with cloth Fig 5 5 Parts to remove Remarks and procedures Fasteners Governor system 1 Loosen the bolt and remove the governor lever from the governor shaft There is no need to remove the bolt 10 mm box spanner or spanner M6 x 30mm 1 pc 3 2 Remove the governor spring 3 Remove the governor rod and the rod spring from the carburetor Carburetor Insulator Remove the carburetor from the cylinder head 10 Remove the insulator Speed control lever and Bracket Remove the speed control lever and bracket from the cylinder head 10 mm box spanner M6 x 12mm 2 pcs GOVERNOR LEVER GOVERNOR ROD and ROD SPRING des GOVERNOR SPRING SPEED CONTROL LEVER and BRACKET GASKET CARBURETOR INSULATOR Step Parts to remove Remarks and procedues Fasteners Ignition coil Remove the spark plug cap from the spark plug and 10 mm box spanner remove the ignition coil from the crankcase M6 x 25mm 2 pcs Starting pulley Remove the starting pulley from the flywheel 19 24 mm box spanner or Fit a box wrench or a socket wrench on the flywheel nut socket wrench M14 nut and loosen the nut by knocking the wrench sharply with a Models EX13 17 and 21 hammer See Fig 5 10 M18 nut Model EX27 NOTE 1 Do not insert a screwdriver or other object between the flywheel blades otherwise the risk of damagin
30. KSHAFT a Wrap the key way portion of the crankshaft with polyvinyl tape and insert the crankshaft into the crankcase taking care not to damage the oil seal lip SWN b Insert the woodruff key for the flywheel magneto NOTE Do not insert the woodruff key before inserting the crankshaft into the crankcase POLYVINYL TAPE Fig 5 30 _ 29 3 AND 5 RINGS OPEN ENDS OF PISTON RING Install each piston ring in the correct groove of the piston by widening it enough to slide it over the piston NOTE Be careful not to twist the rings too much as they may be damaged Install the oil ring first followed by the second ring and then the top ring When installing the second ring make sure that the N mark is face up zJ See Fig 5 33 Fig 5 31 BARREL EX13 27 TAPER EX17 21 SECOND RING TAPER CUTTER RING WITH COIL EXPANDER THREE PIECE CONSTRUCTION Fig 5 32 MARK R MARK EX13 EX17 EX21 EX27 Fig 5 33 30 4 PISTON AND CONNECTING ROD The piston is attached to the connecting rod by the piston pin When assembling the piston and connecting rod make sure to align the mark on the piston head with the MAG mark on the connecting rod NOTE 1 Before assembling the connecting rod apply oil to its small end NOTE 2 Be
31. NOTE Since the spring is stored in the reel make sure not to drop or shake the reel after removing it Place it on a level surface such as a table Disassembly is completed NOTE Put on the protective glasses prior to start reassembly 13 1 2 REASSEMBLY PROCEDURE 1 Put the reel back into the case GREASE 1 Apply grease to the surface of the case Fig 13 3 2 Adjust the position of the inner end of the spring in the reel Fig 13 4 3 Hold the reel in such a way that the inner end of the spring hooks onto the shaft hook and then place the reel carefully back into the case SHAFT HOOK Fig 13 3 Position where the inner end of the spring touches to the rib of the bearing 4 Turn the reel gently counterclockwise to confirm that the spring is hooked Fig 13 4 _ 62 2 Mount the components 1 Mount the ratchet into the reel Fig 13 5 THE RATCHET SHOULD BE IN THE CLOSED POSITION Fig 13 5 2 Mount the ratchet guide assembly taking care 0 not to move the ratchet Fig 13 6 Ratchet guide 653 Friction spring Ratchet guide sub assembly 3 Tighten the set screw Fig 13 6 1 Hold the ratchet guide gently by your hand to prevent it from rotating then tighten the set screw Tightening torque M6 5 5 55 kgf cm 4 0 ft Ib 4 Tension the reel spring 1 Grip the case and tu
32. P ADVANCING IGNITION TIMING 1 At lower speed of the engine Rotation of the flywheel induces current l1 EDO 1000 2000 3000 rp m as this current flows through the base terminal ENGINE REVOLUTION of the power transister it is activated and the current 12 starts flowing Figs As the engine reaches the ignition timing the ignition timing control circuit for the lower engine speed is activated and lets the current Is flow through the base terminal of the power transistor This generates the collector current la which will bypass the current H and abruptly shut off the current 12 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 h as this current flows through the base terminal of the power transistor it is activated and the current l2 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 ls to the power transistor This current induces the collector current le and will bypass the current H to shut down the current I2 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
33. SERVICE MANUAL Models 13 17 21 27 ENGINES PUB ES1934 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 Copyright 2005 Robin America Inc Section Title Page 1 2 PERFORMANCE 2 g FEATURES SLA 7 4 GENERAL DESCRIPTION OF ENGINE COMPONENTS 8 5 DISASSEMBLY AND REASSEMBLY 14 5 1 PREPARATIONS AND PRECAUTIONS r 14 5 2 SPEGIAL TOOLS 14 5 3 DISASSEMBLY PROCEDURE 15 5 4 HEASSEMBLEEPHROGOEDUNRE u R ana 29 6 ENGINE QOIL PROP 47 48 B WIRING DIAGRAM axe E pH MN EPxkENRE xU CEMEM CENUJMM CU C aS UV CE CPGE PEE CHE MpEEd cad NEUE 51 9 ELECTRIC 53 10 OIL SENSOR U I M 55 11 AUTOMATIC DECOMPRESSION SYSTELM 56 12 GARBURETOR fec
34. X13 EX17 and EX21 in such as Chain Guide Air Cleaner Ignition Coil etc Only with ordinary tools routine maintenance assembly and disassembly can be performed 3 4 EXTREMELY ADVANCED TECHNOLOGY Extreme reliability and durability are achieved by Heavy Duty Chain Driven OHC System Oval type case hardened steel links enhance performance and resist stretching which result in extended maintenance free operation Completely New Main Bearing Cover s Design Flush mounted main bearing cover with lower moment of deformation significantly increases reliability and engine life Superior Cooling and Lubrication System Heat reduction is achieved by more efficient larger and more numerous cooling fins on crankcase cylinder and mounting base as well as by outstanding oil delivery system Large Ball Bearings on both ends of crankshaft for maximum stability under demanding loads Cast Iron Cylinder Liner resists wear 3 5 EXTREME POWER AND PERFORMANCE Extremely Higher Power and Lower Fuel Consumption are realized by High speed and homogeneous combustion achieved by sophisticated Pentroof Combustion Chamber which includes Intake and Exhaust Valves located at optimum angle Straight Intake Port with minimal air flow resistance Environmentally friendly EX engines comply with EPA Phase 2 and CARB Tier II Emission Regulations in the USA Extreme application compatibility With four versatile models existing slant cylinder engines can be ea
35. buretor body Through the operation of the float and the needle valve the float chamber maintains a constant fuel level while the engine is working The fuel flows from the tank into the float chamber through the needle valve When the fuel rises to a specific level the float rises When the buoyancy of the float is balanced with the fuel pressure the needle valve shuts off the fuel passage thereby maintaining the fuel at the predetermined level 12 2 2 PILOT SYSTEM The pilot system supplies fuel to the engine during idling and low speed operation Fuelis initially metered by the main jet and then metered once again by the pilot jet At the pilot jet the fuel is mixed with air metered by the pilot air jet and then the fuel air mixture is fed to the engine through the pilot outlet and the bypass During idling fuel is fed to the engine mainly through the pilot outlet 12 2 3 MAIN SYSTEM The main system feeds fuel to the engine at medium and high speed operation Fuel is metered by the main jet and flows into the main nozzle Air metered by the main air jet is mixed with fuel through the bleed holes of the main nozzle The fuel air mist is injected into the Venturi and mixed once again with air from the air cleaner This fuel air mixture is now of optimum concentration and is fed into the combustion chamber of the engine 12 2 4 CHOKE SYSTEM The choke system is for easier start of the engine in cold weather conditions When the engine is
36. by the flywheel and will be damaged cds 3 Mount the fuel tank on the crankcase M6 nut 2 pcs M6 X 25 mm bolt 1 pc Models EX13 17 and 21 M8 X 25 mm bolt 2 pcs Model EX27 Fig 5 59c 27 BLOWER HOUSING AND RECOIL STARTER 1 Mount the ignition coil cord on the crankcase by aligning it with the baffle 1 case 2 Mount the blower housing on the crankcase M6 x 12 mm bolt 4 pcs 3 Mount the recoil starter on the blower housing M6 x 8 BOLT 4 pcs M6 x 8 mm bolt 4 pcs M6 x 12 BOLT 4 pcs 28 STOP SWITCH E _ N STOP SWITCH 1 Mount the stop switch the blower housing 2 Refer to the wiring diagram See page 51 and 52 for wiring details Fig 5 61 29 AIR CLEANER Mount the air cleaner element and cleaner cover 2U F 5 A Oil Dual element 45 30 EXTERNAL INSPECTION Reassembly is completed Check that the wiring is correct and that there are no loose nuts and bolts or any other faults visible on the outside of the engine 31 FILLING WITH ENGINE OIL Use the automobile engine oil of API service class SE or higher grade The amount of oil depends on the engine model Refer to the table below Model Model Model Model EX13 EX17 EX21 EX27 Engine oil volume 0 6L 1 0L 32 BREAK IN OPERATION A new engine or an engine
37. c switch e Repair or replace starter magnetic switch OK OK Y e Check settling of spring and Check engagement of N NG 22 and ring gear 2 gear end face is Correction of pinion ga OK Y p gap Y With starter alone connect the battery terminal Check pinion roller clutch NG Replace motor for damage or replace and the M or K terminal of brush holder or armature the starter and check if motor runs OK Y Check battery charged There i state and battery terminal Mie 2 EE F connection or corrosion p arter 2 for abnormality r ease Y Cheek battery charged e Charge or replace the batter slow state battery terminal NG 9 y Normal rotation e Repair connection or connection or corrosion corrosion of battery terminals for any abnormality OK Y OK Check ignition system Y and fuel system Check viscosity of engine NG oil for any abnormality Change the engine oil OK Y Replace the starter with a NG new one and check if it gt Check the engine interior runs Repair replace the starter X When the starter continuously runs Immediately remove the terminal of the battery Motor does not stop even when the key switch is turned off gt Repair or replace the key switch or starter magnetic switch 71 Problem
38. cap EX13 17 21 13 0 15 0 130 150 10 8 polig EX27 17 0 20 0 170 200 5 Flywheel nut 59 0 64 0 590 640 42 7 46 3 Main bearing cover bolts 220 240 220 240 16 2 17 7 New 12 0 15 0 120 150 8 7 10 8 Spark plug Re tightening 23 0 27 0 230 270 16 6 19 5 Muffler nut 18 0 22 0 180 220 13 0 15 9 Ignition coil 7 0 9 0 70 90 5 1 6 5 f 17 MAINTENANCE AND STORAGE The maintenance jobs described below apply to correct use of the engine under normal conditions The maintenance intervals mentioned in this section are not a guarantee that no maintenance is required during those intervals For example when the engine is used in dusty conditions the air cleaner should be cleaned every day rather than every 100 hours 17 1 DAILY MAINTENANCE EVERY 8 HOURS OF USE MAINTENACE ITEMS REASON REMARKS 1 Clean dust from engine 2 Check for fuel leakage Tighten or replace parts if necessary 3 Check all parts are securely fastened Tighten if necessary 4 Check oil level and add up to full mark 5 Check that the air cleaner element is clean Clean or replace if necessary 1 Dust can impair operation of various parts Governor linkage is especially sensitive to dust 2 Uneconomical and dangerous 3 Looseness can result in vibration and accidents 4 Running the engine with insufficient oil can result in serious problems including
39. ck pressure of exhaust system Check and clean or replace 5 Overloading Adjust to rated load 1 Carburetor system 1 Low idling speed Adjust 2 Slow system passage clogged Check and clean 2 Intake system TENES 1 Check and tighten 1 Air mixing from air intake system joints replace gasket c 5 3 head 1 Gasket faulty blow by Replace 4 Valve system 1 Improper valve clearance Adjust oc 2 Leakage from valve seat Repair 3 Excessive clearance between valve stem and Replace 5 Ignition system 1 Weak spark 69 Check adjust replace plug Problem and possible cause Remedy 1 Oil leakage 1 Loose oil drain plug Tighten 2 Faulty oil drain gasket Replace 8 3 Loose main bearing cover bolts Tighten 4 Faulty main bearing cover gasket Replace 5 Crankshaft oil seal front rear defect Replace 2 2 Oil up 1 Faulty piston oil ring Replace 5 2 Piston ring seizure wear poor contact Replace 5 3 Excessive wear of piston and or cylinder Replace E 4 Faulty stem seal Replace 5 Excessive oil level Adjust oil level 6 Breather defect Repair or replace 1 Fuel system 1 Clogged air cleaner Clean or replace 4 Valve system problems 1 Improper valve clearance c lt Morus valve high fuel level Repair or replace 5 3 Choke does not open fully Repair or replac
40. cm 16 6 19 5 Align the top and bottom of the baffle 1 case with the crankcase and mount it with the bolts Model without electric starter M6 x 12 bolt 1 pc Models EX13 17 and 21 Model with electric starter Mount the electric starter and the charging coil referring to the illustrations of disassembly M8 x 12mm bolt 1 pc Model EX27 Tightening torque EX13 17 21 EX27 UPPER 4 0 12 0 N m BAFFLE 40 120 2 9 ftg Ib 8 7 fig Ib Se x 12 FLANGE BOLT 1 pc EX13 17 21 8 x 12 FLANGE BOLT 1 BAFFLE 1 CASE HOOK Fig 5 49a 38 19 FLYWHEEL STARTING PULLEY NOTE When mounting the flywheel be sure to wipe off any oil on the tapered portion of the crankshaft and flywheel Mount the flywheel on the crankshaft Tighten the flywheel together with the starting pulley Tightening torque 59 0 64 0 N m 590 640 kgf cm 42 7 46 3 016 M14 nut 1 pc EX13 17 21 M18 nut 1 pc EX27 20 IGNITION COIL When mounting the ignition coil insert a thickness gauge between the ignition coil and the flywheel to check the air gap Air gap 0 3 0 5 mm Tightening torque 7 0 9 0 Njm 70 90 kgf cm 5 1 6 5 16 M6 x 25 bolt and washer 2pcs FLYWHEEL Fig 5 50
41. d cylinder EX13 0 040 0 079 at skirt 0 0016 0 0031 0 25 rud 0 050 0 089 0 010 EX27 0 0020 0 0035 0 15 0 35 EIS 0 0059 0 0138 Top EX17 0 15 0 3 1 5 EX21 0 0059 0 0118 0 0591 0 1 0 3 0 0039 0 0118 0 15 0 35 EXIS 0 0059 0 0138 Second m 0 0591 EX27 0 0078 0 0157 0 2 0 4 EN 0 0078 0 0157 Oil EX17 0 05 0 25 1 5 Coil exp 21 0 0020 0 0098 0 0591 0 1 0 3 ERU 0 0039 0 0118 JB Unit mm in ITEM STD Limit CONNECTING ROD Large end inner diameter EX13 EX21 1 1811 1 1817 1 1850 34 500 34 516 34 1 1 3386 1 3392 1 3425 Clearance between large end and crank pin EX13 EX17 0 020 0 049 0 2 21 0 0008 0 0019 0 0078 EX27 Small end inner diameter EX13 13 010 13 021 13 08 0 5122 0 5126 0 5150 EX17 16 010 16 021 16 08 EX21 0 6303 0 6307 0 6331 18 010 18 021 18 08 0 7091 0 7095 0 7118 Clearance between small end and piston pin EX13 EX17 0 010 0 029 0 12 21 0 0004 0 0011 0 0047 27 Large end side clearance T EX13 NN EX17 0 100 0 780 1 0 21 0 0040 0 307 0 0394 o 1 II J EX27 CRANKSHAFT i i EX1 Crank pin outer diameter B 29 967 29 980 29 85 EX21 1 1798 1 1803 1 1752 34 467 34 480 34 35 1 3570
42. e 3 2 Engine core components 1 Low compression Check and repair Check and adjust load 2 Qvercooling and or engine speed 1 Ignition system problems 1 Loose ignition system wiring Inspect and tighten 2 Improper or faulty spark plug Clean or replace 2 Fuel system problems 1 Lean or rich fuel air mixture Clean adjust or replace carburetor 9 2 Carburetor contamination Overhaul or clean 3 Dirty or clogged fuel lines Clean or replace 4 Air from air intake system joints Tighten replace gasket 3 Oylinder head 1 Carbon deposit in combustion chamber Clean 2 Leakage from cylinder head gasket Replace Adjust 2 Valve heat deterioration Replace 3 Worn or broken valve spring Replace 4 Improper valve timing Adjust ELECTRIC STARTER Engine does not start e Charge or replace the battery corrosion of battery terminals Y Check battery charged Does the NG Does the NG state and battery terminal NG e Repair connection or crank run starter run connection or corrosion 2 for any abnormality OK e Key switch e Connected state Operation sound of NG e Check repair wiring to the magnetic switch of starter gt starter magneti
43. e following Use a V belt rather than a flat belt The drive shaft of the engine must be parallel to the drive shaft of the driven machine The drive 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 Abelt tensioner or similar should be installed if no clutch is used 14 5 2 FLEXIBLE COUPLING When using a flexible coupling run out and misalignment between the driven shaft and the engine shaft should be minimized The permissible margin of run out and misalignment is specified by the flexible coupling manufacturer 67 15 TROUBLESHOOTING If the engine shows sign of malfunction the cause should determined immediately and appropriate countermeasures should be taken to prevent the problem from worsening This section describes certain known problems their possible causes and appropriate countermeasures Note however that the list of problems presented here is not all Generally speaking since there is the possibility of multiple causes for a single problem please use your experience and common sense when deciding on what action to take 15 1 ENGINE The following three conditions must be lulfilled for satisfactory engine start 1 The cylinder filled with a proper fuel air mixture 2 Good compression in the cylinder 3 Good spa
44. e piston head then remove the connecting rod bolt 2 Remove the connecting rod cap 3 Rotate the crankshaft until the piston comes to its top position Push the connecting rod and remove the piston from the upper part of the cylinder 10 mm box spanner 6 x 33mm 2 pcs Models EX13 17 and 21 M7 x 40mm 2 pcs Model EX27 26 Piston and piston rings 1 Remove the piston clips 2 pcs Take out the piston pin and then remove the piston from the connecting rod small end taking care not to damage the connecting rod small end 2 Remove the piston rings from the piston by spreading them at the gap Take special care not to damage the rings when doing this CONNECTING ROD CAP PISTON PIN CLIP M6 x 33 EX13 17 21 7 x 40 EX27 CONNECTING ROD BOLT 2 pcs Fig 5 22 27 gt PISTON PISTON RING Parts to remove Remarks and procedures Fasteners Crankshaft 1 Remove the woodruff key for the flywheel magneto 2 Remove the crankshaft from the crankcase by tapping its magneto side end with a plastic Plastic hammer hammer taking care not to damage the oil seal See Fig 5 24 27 Oil sensor option 1 Remove the clamp See Fig 5 25 M6 x 12mm 1 pc 28 2 Remove the oil sensor from the crankcase M6 x 16mm 2 pcs M6 x 10 TAPPING BOLT 1 pc EX27 only PLATE lt gt Fo
45. ease recommended or engine oil when the starter is disassembled and prior to long term storage APPLY GREASE by S 2 an 0 Fig 13 11 _ 65 14 INSTALLATION Installation has a decisive influence on engine life ease of maintenance and inspection frequency of inspection and repair running costs and other related aspects Before installing the engine be sure to plan the installation with care taking the points below into account 14 1 INSTALLING When installing the engine pay special attention to the position of installation the method for coupling with working equipment and the foundations and supports for the engine Position the engine so that tasks such as gasoline and oil replenishment and inspection spark plug inspection air cleaner maintenance oil drainage and so on can be carried out as easily as possible 14 2 VENTILATION An engine requires fresh air for cooling and for burning fuel When an engine is covered with a bonnet or is operated in an enclosed space the temperature around the engine rises and this causes such problems as vapor lock oil deterioration increased oil consumption power loss engine seizure and reduced engine life making it difficult for the engine to function normally It is thus necessary to install ducts and dampers to guide fresh air so as not to recycle the hot air used to cool the engine and to prevent the working equipment from heating up
46. ed by centrifugal force and compression is fully utilized to produce power 41 STD Dual Element CLEANER e VER c 0 CLEANER Y URETHANE ss Fig 4 13 Fig 4 14 ROCKER ARM EXHAUST VALVE SIDE EXHAUST VALVE CAMSHAFT Fig 4 15 4 18 SECTIONAL VIEW OF THE ENGINE Cross sectional view across the shaft TANK CAP FUEL TANK GOVERNOR SHAFT BLOWER HOUSING GOVERNOR LEVER GOVERNOR GEAR CRANKSHAFT CONNECTING ROD STARTING PULLEY RECOIL STARTER FLYWHEEL CHARGE COIL OIL SENSOR MAIN BEARING COVER OPTION OPTION Fig 4 16 Cross sectional view along the shaft FUEL STRAINER PISTON MUFFLER GOVERNOR LEVER CHAIN GUIDE MUFFLER
47. engine Seizure 5 A clogged air cleaner can cause power loss and malfunction 17 2 INSPECTION AND MAINTENANCE AFTER THE FIRST 20 HOURS MAINTENACE ITEMS REASON REMARKS 1 Change the crankcase oil 1 Sludge is deposited during running in 17 3 INSPECTION AND MAINTENANCE EVERY 100 HOURS EVERY 10 DAYS MAINTENACE ITEMS REASON REMARKS 1 Change the crankcase oil 2 Clean the air cleaner 3 Inspect the spark plug Clean with gasoline or polish with sandpaper if dirty 1 Contaminated oil quickens wear 2 A clogged air cleaner can cause engine malfunction 3 A faulty spark plug can cause low power output and poor starting performance 17 4 INSPECTION AND MAINTENANCE EVERY 100 TO 200 HOURS EVERY MONTH MAINTENACE ITEMS REASON REMARKS 1 Clean the fuel strainer and fuel tank 2 Change the air cleaner element 1 Contaminated fuel can cause engine malfunction 2 A clogged air cleaner can cause engine malfunction _ 81 17 5 INSPECTION AND MAINTENANCE EVERY 300 HOURS MAINTENACE ITEMS REASON REMARKS 1 Inspect the intake and exhaust valve clearance Adjust if necessary 1 Incorrect clearance can cause low power output and engine malfunction 17 6 INSPECTION AND MAINTENANCE EVERY 500 TO 600 HOURS EVERY 6 MONTHS MAINTENACE ITEMS REASON REMARKS 1 Remove the cylinde
48. er transistor turns OFF and the current l gt is shut off abruptly resulting in the high voltage generated in the secondary coil which produces sparks at the spark plug The ignition timing at lower engine revolution is less advanced as shown in the above chart At higher engine revolution over 2 000rpm advancing control circuit operates to run the gate current l4 to turn the control thyristor ON thus the current h bypass the thyristor as current ls At this moment the power transistor 2 turns OFF and the current l gt is shut off abruptly resulting in the high voltage generated in the secondary coil which produces sparks at the spark plug At over 2 000rpm ignition timing on each engine revolution is controlled by advancing control circuit that receive electrical information from revolution sensing resister The advancing of ignition timing from lower to higher engine revolution changes lineally as shown in the above chart _ 50 8 WIRING DIAGRAM 8 1 MODEL WITHOUT ELECTRIC STARTER Models EX13 17 21 and 27 Spark plug peo Black 4 lt S 3 i Ignition coil ay built in transistor a Flywheel Fig 8 1 8 2 MODEL WITH ELECTRIC STARTER Models 17 21 Spark plug gt 4 Black 77 Black Magneto Ignition coil Key switch Charge coil ra Diode rectifier Lt Blue Green Black Green LA106 LA
49. 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 _ 49 7 4 SYSTEM 27 7 4 1 7 4 2 7 4 3 a IGNITION COIL INTERNAL CIRCUIT Base Resister h e 5 3 E gt E E B 2 S 4 S S ls gt a amp Low Speed Ignition 2 2 Timing Control 8 9 Circuit 5 i 1 Advancing Control 24 Circuit la Is 52 6 za e e e e Fig 7 2a IGNITION TIMING CHARACTERISTIC LINEAR ADVANCING cb ck IGNITION TIMING B T D C 500 1000 1500 2000 2500 3000 3500 4000 ENGINE REVOLUTION R P M Fig 7 2b BASIC THEORY Revolution of the flywheel generates electricity on the primary side of the ignition coil and the base current h flows to the power transistor Current l turns the power transistor and the electric current flows This is the same situation when the contact breaker is closed in a case of breaker point type ignition system At lower engine revolution the low speed ignition timing control circuit operates to run the gate current Is to turn the control thyristor ON thus the current h bypass the thyristor as current Is At this moment the pow
50. g parts such as the friction spring 2 Pull out the starter knob as far as it will go a If the starter rope remains in the rope slot in the reel the spring may be over stressed fix this pull out the starter rope approximately 30 cm and controlling the rotation of the reel with your thumb allow the starter rope to rewind about 1 or 2 turns b If the starter rope rewinds slowly or only partially apply grease or oil to the rotary parts or the friction surfaces If this does not help try winding up the spring 1 or 2 turns taking care not to over stress the spring If there is a sound indicating that the spring is off the hook and the starter rope does not be wound back reassemble the recoil starter from the beginning 13 1 4 OTHER GUIDES 1 If the spring escapes from the reel during STARTER disassembly N a Hook the outer end of the spring onto the gap WLS in the reel and rewind the spring holding the spring with your fingers so as to prevent it from springing out of the housing unit Wear protective gloves when doing this Hook the outer end of the spring onto the gap in the reel Fig 13 10 b Hook the inner end of the spring onto the STARTER REEL projection on the starter case SPRING Refer to the assembly procedure for more details 2 About lubrication Lubricate the rotating and frictional parts and the spring with grease heat resistant gr
51. g the blades might be occured 2 Knock the wrench with a hammer in a counter clockwise direction 3 The fan of the Model EX21 engine is made of synthetic resin Take the utmost care when handling it Flywheel Remove the flywheel from the crankshaft Leave the nut Flywheel puller temporarily to prevent the flywheel from dropping out Fit the flywheel puller as shown in Figure 5 11 and remove the flywheel from the crankshaft by rotating the bolt at the center in a clockwise direction Knock the center bolt with a hammer sometimes 14 ATTACH NUT TEMPORARILY FLYWHEEL PULLER Fig 5 11 M14 NUT 1 pc 13 17 21 STARTING M18 NUT 1 pc EX27 PULLEY PAL M6 x 25 BOLT and Parts to remove Remarks and procedures Fasteners Electric starter option 1 Disconnect the grounding cable from battery Control box 2 Disconnect the wire leading from the key Diode rectifier switch ST terminal to the magnetic switch 12 mm box spanner 15 Magnetic switch 3 Disconnect the wire that connects the M8 nuts positive terminal of the battery to the magnetic switch 4 Remove the electric starter 10 mm box spanner 12 mm box spanner ELECTRIC STARTER option M6 NUT 1 pc EX17 21 M8 NUT 1 pc EX27 21 M8 x 28 BOLT 2 pcs UPPER SIDE M6 x 30 FLANGE BOLT 1 pc DOWN SIDE M6 x 20 FLANGE BOLT
52. ilot air jet 12 3 3 PILOT SYSTEM 1 Remove the pilot jet Use the correct tool so as to avoid damaging the jet 2 When reassembling the pilot jet be sure to firmly tighten it otherwise fuel may leak leading to engine malfunction 12 3 4 MAIN SYSTEM 1 2 3 4 Remove the amp and remove the float chamber body 9 Remove the main jet from the body Remove the main nozzle 2 from the body When reassembling the main system be sure to fasten the main jet and main nozzle firmly to the body otherwise the fuel concentration in the fuel air mixture may become too rich leading to engine malfunction 5 The tightening torque of the amp is 9 N m 90 kgf cm 6 5 ft Ib Be sure not to forget to mount the washer eer A 12 3 5 FLOAT SYSTEM 1 Take out the float pin 49 and then remove the float amp and the needle valve Since the needle valve is linked to the float 0 take care when assemble Do not use drill or similar objects for cleaning the jets as these are likely to damage the orifices which in turn can impair fuel flow Use compressed air to clean the jets The float pin is pressed into the carburetor body When removing the needle valve and the float a rod or a similar tool slimmer than the float pin should be used Tap the reverse side gently and remove 60 13 RECOIL STARTER 13 1 RECOIL STARTER Tools required Screwdriver pliers and protective
53. ine at a constant speed even with load variations The governor flyweights are mounted on a governor gear GOVERNOR GEAR Fig 4 9 4 10 COOLING SYSTEM The engine uses a forced air cooling system in which a cooling fan which also works as a flywheel forces cooling air into the cylinder and the cylinder head Baffles are provided to guide the flow of the cooling air Model EX21 is provided with a synthetic resin cooling fan that is separate from the flywheel 4 11 LUBRICATION SYSTEM The rotating parts sliding parts and valves of the engine are lubricated with oil in the crankcase The oil is splashed onto the parts by the oil splasher on the connecting rod 4 12 TIMING CHAIN Timing chain system is adopted and designed for lubricating for the upper portion of cylinder head The timing chain is engaged between the sprocket portion of integrated camshaft in the cylinder head and the crankshaft gear sprocket The sprocket teeth in particular shape are adopted to enhance the durability and to realize low noise level 4 13 IGNITION SYSTEM The ignition system is a transistor controlled magneto system with the ignition timing set at 23 degrees 13 17 21 27 degrees EX27 before the top dead center The magneto consists of a flywheel and ignition coil The flywheel which also works as a fan is directly mounted on the crankshaft and the ignition coil is directly mounted on the crankcase
54. lead switch incorporated Type Resistance at FULL oil level 100 M ohms or over Operating 30 to 180 degree Celsius Temperature 10 2 CONSTRUCTION AND OPERATION The oil sensor is composed of the float permanent magnet incorporated into the float and the oil sensor In accordance with the oil level the float moves up and down EE When the oil level is upper level the float moves up FLOAT PERMANENT MAGNET LEAD SWITCH Fig 10 2 When the oil level is lower level the float moves down The permanent magnet is close to the lead switch and the lead switch is activated by the magnetic force MAGNETIC FORCE Fig 10 3 NOTE With regards to the wiring diagram please refer to the section 8 4 52 55 11 AUTOMATIC DECOMPRESSION SYSTEM 11 1 FUNCTIONS AND CONSTRUCTION EX series engines employ an automatic decompression system as a standard feature This enables easy starting of the engine with lighter recoil pull The automatic decompression system releases the compression of the engine by lifting up the exhaust valve at cranking speed The following is the explanation of the function At the end of the compression process the release lever lifts up the rocker arm exhaust which in turn opens up the exhaust valve slightly to release the c
55. ollowing charts are made in conformity with SAE internal combustion engine standard test code J1349 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 engin s life and fuel consumption When the engine is installed on a certain equipment it is recommended that the continuous output required from the equipment to 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 a specific r p m 2 4 PERFORMANCE CURVES OUTPUT HP 5 0 4 0 3 0 2 0 1 0 st A RECOMMENDED HORSEPOWER 2000 2400 2800 3200 3600 4000 REVOLUTION gt r p m a kgf 0 9 0 8 0 7 3 TORQUE gt OUTPUT HP 6 0 5 0 4 0 3 0 2 0 1 0 EX17D kW 4 5 4 0 3 5 3 0 2 5 2 0 1 5 1 0 0 5 0 2000 2400 RECOMMENDED HORSEPOWER 2800 3200 3600 REVOLUTION s r p m N m 12 0 11 0 4000 kgf m 1 2 1 1 1 0 0 9 TORQUE OUTPUT PS 7 0 6 0 5 0 4 0 3 0 2 0 Wr mm MAXIMUM HORSEPOWER NP Lati SERE Ed HP i Lee 1 2000 2400 2800 3200 3600 40 REVOLUTION r p m
56. ompression 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 above the cam profile and lifts up the rocker arm exhaust because the force of the return spring on the weight is larger than the centrifugal force on the weight S ROCKER ARM EXHAUST ROCKER ARM ROCKER ARM M RELEASE LEVER INTAKE I Ors CAM S CRESCENT CAM RELEASE LEVER CAMSHAFT A Fig 11 1 DETAIL A When the cranking speed reaches a specified r p m the crescent cam is retracted under the cam profile because the centrifugal force applied to the flyweight becomes larger than the force of the return spring on the weight and thus it is shifted to the position shown in the illustration below RELEASE LEVER ROCKER ARM ROCKER ARM ROCKER ARM EXHAUST INTAKE CAM CRESCENT A 7 CON AMSHAFT A RELEASE LEVER f DETAIL Fig 11 2 11 2 INSPECTION When assembling the release lever make sure that it works smoothly 56 12 CARBURETOR 12 1 SPECIFICATIONS EX13 EX17 EX21 EX27 A C Type STD DUAL STD DUAL STD DUAL STD DUAL Main Jet 70 0 68 8 81 3 80 3 86 3 83 8 98 0 96 0 Pilot Jet 40 0 40 0 40 0 40 0 41 3 lt 40 0 Pilot Screw Turning 1 3 4 lt 1 1 4 lt 1 lt 1 1 2 lt 12 2 FUNCTIONS CONSTRUCTION 12 2 1 FLOAT SYSTEM The float chamber is located below the car
57. on is an aluminum alloy casting with grooves for mounting two compression rings and one oil ring 4 5 PISTON RINGS The piston rings are made of special cast iron The profile of the top ring is a barrel face or tapered face and that of the second ring is a tapered face There are 2 types of oil ring depending on the engine specification As those are interchangeable the cutter ring with coil expander type can be selected as the spare part BARREL 13 27 TAPER EX17 21 SECOND RING TAPER CUTTER RING WITH COIL EXPANDER THREE PIECE CONSTRUCTION Fig 4 5 4 6 CAMSHAFT The camshaft and the sprocket are made of special sintered alloy They are constructed as a single piece The camshaft is provided with intake and exhaust cam and the decompression release lever is mounted on the sprocket shaft end side 4 7 VALVE ARRANGEMENT This engine has a chain driven overhead cam and overhead valve construction with a single cam performing both intake and exhaust operations 4 8 CYLINDER HEAD The cylinder head is an aluminum die casting with a pent roof combustion chamber construction The intake and exhaust ports are arranged in a cross direction to improve combustion efficiency 4 9 GOVERNOR SYSTEM This engine is equipped with a centrifugal flyweight type governor that makes it possible to operate the eng
58. ontactor is heard If the pinion does not operate or magnetic switch sound is not heard check continuity of each coil of magnetic switch 1 If the pinion operates or contactor sound is heard step to 4 Checking of magnetic switch 1 2 In case of no continuity Replace the magnetic switch 3 When continuity is OK Step to 4 Checking of magnetic switch 2 4 Checking of magnetic switch 1 Operate the magnetic switch and check B M terminals 2 Check the magnetic switch plunger and bobbin interior for dust sticking or rusting 1 In case of no continuity Contact continuity failure Replace the magnetic switch 2 When continuity is OK Step to 5 Motor checking 1 Clean the plunger If the bobbin interior is contaminated replace the magnetic switch 5 Motor checking Connect the side of the battery to the M terminal of magnetic switch and check if the motor runs 1 If the motor does not run check electric circuit inside the motor field coil armature and brush and replace faulty parts 72 Problem and check item Description Remedy Check engaged state of pinion and ring gear 2 Starter runs but engine not Motor idles and engine does not run 1 Remove and check the starter Check or replace the pinion clutch if necessary 2 Check battery charged state and battery terminal connection or corr
59. osion for any abnormality If pinion and ring gear do not engage with each other and abnormal noise is heard between end faces of pinion and ring gear check the starter pinion and ring gear RING GEAR PINION GEAR 1 Remove the starter and check pinion and ring gear end faces If worn replace the pinion and ring gear 2 In case of sliding fault of the pinion correct it 3 If shift lever or spring is deformed replace it 3 Both starter and engine run but the engine does not start Check if the rotation speed is normal or slow If slow check the battery and engine oil viscosity 1 When the rotation speed is normal Check the ignition system and fuel System 2 When the rotation speed is slow a Check the battery b Check the viscosity of engine oil If not normal change the oil c If both a and b are normal Remove and check the starter 16 STANDARD REPAIR TABLES 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 16 1 STANDARD DIMENSIONS AND LIMITS OF USE Unit mm in ITEM STD Limit CYLINDER HEAD Flatness EX13 EX17 0 05 0 1 EX21 0 002 0 004 EX
60. osity shown the table above depending environmental air temperature When the air temperature falls below 20 or rises above 40 be sure to choose engine oil of appropriate viscosity and grade according to the prevailing conditions Care must be taken when using multi grade engine oil because the oil consumption rate tends to increase when the air temperature is high 6 3 ADDING AND CHANGING ENGINE OIL O Engine oil inspection and filling up Every time you use the engine add engine oil up to the designated maximum level O Engine oil change First time After 20 hours use Thereafter Every 100 hours use 47 7 7 1 MAGNETO The Robin Engine uses a T I C type breakerless magneto ignition system 1 TRANSISTOR IGNITER CIRCUIT has the ignition coil outside the flywheel which is the standard specification A charge coil system is available as an option The flywheel is a specialized piece of equipment As for the lighting coil the ignition coil is outside the flywheel and a lighting coil is inside 7 2 INSPECTING THE MAGNETO If the engine does not start has difficulty starting or does not run smoothly check the magneto for defects according to the following procedure 1 Carefully check the high tension cable for any damage or short circuiting 2 Check the sparking Take the spark plug out of the
61. r charge coil only WOODRUFF KEY CRANKSHAFT Fig 5 23 28 5 4 REASSEMBLY PROCEDURE 5 4 1 NOTES REASSEMBLY 1 Clean the each parts carefully taking special care with the piston cylinder crankshaft connecting rod and bearings 2 Scrape off any carbon deposits on the cylinder head and the piston head Be particularly careful when removing carbon from the piston ring grooves 3 Inspect the oil seals for any damage to the lip Replace them if damaged Apply oil to the lip before reassembly 4 Replace all the gaskets with new ones 5 Replace the keys pins bolts and nuts with new ones if necessary 7 When reassembling the engine apply oil to all moving parts 8 Check clearances and end plays and adjust if necessary 3 4 5 6 Tighten nuts and bolts to the specified torque settings 7 8 9 When mounting any major part during reassembly of the engine rotate it with your hand to check for any jamming or abnormal noise 5 4 2 ASSEMBLY STEPS AND PRECAUTIONS 1 OIL SENSOR a Mount the oil sensor and fix the wire with the clamp b Mount the shield plate only for charge coil type Tightening torque 10 0 100 kgf cm OIL SENSOR 7 2 ft Ib BOLT 2pcs c Mount the control unit Fix the earth wire of the control unit at the same time See Fig 5 49a on page 38 SHIELD PLATE OS M6 x 12 BOLT 1pc Fig 5 29 2 CRANKSHAFT CRAN
62. r head and remove any carbon 2 Disassemble and clean the carburetor 1 Carbon deposits can cause engine malfunction 2 A faulty carburetor can cause engine malfunction 17 7 MAINTENANCE EVERY 1 000 HOURS ANNUAL MAINTENANCE MAINTENACE ITEMS REASON REMARKS 1 Overhaul the engine Clean and correct the engine parts replacing if necessary 2 Replace the piston rings 3 Replace the fuel hose 1 Dirty misaligned or worn parts can cause low power output and engine malfunction 2 Faulty piston rings can cause low output power and engine malfunction 3 To prevent fuel leakage and attendant dangers 17 8 ENGINE STORAGE 1 Carry out the maintenance jobs described in step 16 1 above 2 Drain fuel from the fuel tank and carburetor float chamber 3 To prevent rust in the cylinder bore inject oil through the spark plug hole pull the recoil starter knob gently 2 or 3 times and then put back the spark plug 4 Pull the recoil starter knob until the resistance is heavy Leave it in that position b Clean the exterior of the engine with an oiled cloth Place a plastic cover or similar over the engine and store the engine in a dry place 82 PRINTED IN THE USA
63. rk properly timed to ignite the mixture The engine cannot be started unless these three conditions are met There are also other factors which make engine start difficult e g a heavy load on the engine when it is about to start at low speed and a high back pressure due to a long exhaust pipe Problem and possible cause Remedy 1 Ignition system problems 1 Spark plug Improper spark plug gap Adjust the gap Insulation defect Replace Carbon deposits Clean 2 Ignition coil Insulation defect or discontinuity Replace Poor contact or broken wire Repair or replace 3 Improper air gap between ignition coil and flywheel Adjust 2 Fuel system problems 1 No fuel in fuel tank Refill 2 Fuel hose clogged or pinched Clean or replace 3 Air in fuel lines Check and retighten joints 3 4 Poor quality gasoline or water gasoline Replace 5 Carburetor Overflow Adjust Clogged or damaged Overhaul 5 Throttle valve malfunction Check and adjust does not close fully 3 Engine core components 1 problems Insufficient tightening of cylinder head bolts Check and retighten 2 Wearing of piston piston rings and or cylinder Repair or replace 3 Improper contact of valve and seat Repair 4 Valve sticking Repair 5 Improper valve clearance Adjust 6 Leakage from intake manifold gasket Retighten replace gasket 7
64. rn the reel 6 times counterclockwise 2 Fix the reel so that the rope hole in the reel is aligned with the rope guide Fig 13 7 NOTE The spring force reaches its maximum value when the reel is wound up Be careful not to drop it or release your grip on it suddenly 63 5 Install the NOTE This procedure requires 2 people 1 Pass the rope end through the rope guide and the rope hole of the reel and pull through approximately 20 cm out of the reel Fig 13 7 2 Tie a knot in the rope end Fig 13 8 8 Put the rope into the reel taking care that the rope end does not stick up Fig 13 9 4 Grasp the rope firmly with one hand at approximately 50 cm from the rope guide and keep the rope tense taking care that the rope is not pulled into the reel Fig 13 8 Approx 20mm 5 Release the reel carefully and allow the rope to be wound back slowly by the force of the spring until the knob reaches the rope guide Assembly is completed 3 Fig 13 9 The disassembly and the reassembly are completed however carry out the following to check if the necessary components have surely been assembled 64 13 1 3 CHECKING THE RECOIL STARTER AFTER REASSEMBLY 1 Pull the starter knob about 2 3 times a If the starter knob is too heavy to pull check that each parts have been assembled as specified b If the ratchet does not work check for missin
65. sily replaced 4 GENERAL DESCRIPTION OF ENGINE COMPONENTS 4 1 CYLINDER AND CRANKCASE The oylinder and crankcase are aluminum die casting as a single piece A special cast iron cylinder liner is molded into the aluminum die casting The crankcase has a mounting surface on the output shaft side to which the main bearing cover is attached The oylinder is inclined to the right at an angle of 25 degrees from the horizontal as viewed from the output shaft side 4 2 MAIN BEARING COVER The main bearing cover is an aluminum die casting which is mounted on the output shaft side of the crankcase By removing the main bearing cover the inside of the engine can be inspected with ease Pilots and bosses are machined into the cover to facilitate the direct coupling of the engine with machines such as generators and pumps There is an oil filling port with oil gauge on either side of the cover 4 3 CRANKSHAFT The crankshaft is made of spheroidal graphite cast iron and the crank pin is high frequency induction hardened The crank sprocket used to drive the chain and the gear used to drive the governor gear are pressed into the output end of the shaft 4 4 CONNECTING ROD AND PISTON The connecting rod is a specially heat treated aluminum alloy die casting Its large and small ends function as bearings A splasher built into the connecting rod lubricates by splashing engine oil The pist
66. started with a closed choke the negative pressure applied to the main nozzle increases This causes a larger amount of fuel to be drawn into the carburetor which in turn makes it easier to start the engine 2357 FUEL SYSTEM OUTLINE FLOAT CHAMBER Fig 12 1 PILOT OUTLET PILOT JET MAIN NOZZLE FLOAT MAIN JET 58 12 3 DISASSEMBLY AND REASSEMBLY Mechanical failures aside most carburetor malfunctions occur when the fuel air ratio of the mixture is not correct This is usually caused by clogged jets air passages and fuel passages or by variations in the fuel level To get the best possible performance from the carburetor ensure that the each passages are kept clean so that air and fuel can flow freely through them MODEL EX 13 17 21 MODEL 27 4 Ci Op Fig 12 3 59 The procedures for overhauling the carburetor are described below Refer to Fig 11 3 12 3 1 THROTTLE SYSTEM 1 When the throttle stop screw 9615 removed the spring be taken out 2 Remove the phillips screw the throttle valve Q3 then take out the throttle shaft 2 When removing the throttle valve take care not to damage the valve edge 12 3 2 CHOKE SYSTEM 1 Remove the choke valve Then pull out the choke shaft 2 When reassembling the choke shaft be sure to position the cutout on the choke valve facing the p
67. sure to insert the clips in the two ends of the piston pin and check the clips for any play 5 CONNECTING ROD a Install the piston and connecting rod assembly into the cylinder by holding the piston rings with the ring guide with the MAG mark on the connecting rod on the flywheel side If you do not have a ring guide hold the piston rings with the fingers and tap the upper part of the piston with a piece of wood NOTE 1 Apply oil to the piston rings the large end of the connecting rod and cylinder before installing the connecting rod into the cylinder NOTE 2 The piston ring gaps should be positioned around the piston at 90 degree intervals See Fig 5 36 3j When assembling the 77 4 piston and connecting rod make sure to align the mark on the piston head with the MAG mark on the connecting rod PISTON RING GUIDE CONNECTING ROD MAG MARK f SECOND RING OIL RING is Y C Lj Fig 5 36 b Rotate the crankshaft down to the bottom dead center and lightly tap the piston head until the large end of the connecting rod touches the crank pin c To mount the connecting rod line up the matching marks and fit the clinch portions firmly together Tightening torque EX13 17 21 EX27 13 0 15 0 17 0 20 0 N m 130 150 kgf cm 170 200 kgf cm 9 4 10 8 ft Ib 12 3 14 5 ftg lb d Check for
68. t BATTERY MAGNETIC ELECTRIC STARTER SWITCH KEY SWITCH Fig 9 2 There are two energized circuits the magnetic switch M circuit and the starter motor S circuit When the key switch is ON the M circuit is closed the current flows in the direction of the arrows the coil of the magnetic switch is magnetically excited and the contactor is pulled As a result a low current flows through the M circuit and a high starter current flows through the S circuit This energizes the starter motor and cranks the engine gt Engagement of the pinion gear 17 21 When starter motor is started the weight built into the spiral splines located on the shaft moves in the direction of the axis driven by centrifugal force and pushes out the pinion gear and the pinion gear engages the ring gear _ 53 9 3 COMPONENT PARTS Models EX17 and EX21 PINION AY FRONT COVER Q MAGNETIC SWITCH p NN STOPPER SET CABLE Q 2 22 x P A yor BOLT 2 pcs 2 T P d P YOKE We zx WASHER ES P SPRING BRUSH BRUSH HOLDER REAR COVER Model EX27 lt P T d 0 6 92 M eS 5 21 BRUSH CASE METAL aA REAR COVER AUS FRONT METAL THROUGH BOLL 2 pcs PINION STOPPER SET Fig 9 3 54 10 SENSOR 10 1 SPECIFICATIONS Float type with
69. ve a camshaft side crankshaft TIMING MARK ROLL PIN TIMING MARK CAMSHAFT SPROCKET MARK PLATE CHAIN GUIDE FITTING POSITION MARK PLATE FE The mark plate does Model EX21 not have a camshaft side or crankshaft Sprocket side TIMING MARK ROLL PIN TIMING MARK CAMSHAFT SPROCKET CRANKSHAFT SPROCKET Fig 5 41a MARK PLATE 10 MOUNTING THE CAMSHAFT ON THE CYLINDER HEAD Mount the camshaft on the cylinder head by inserting the pin camshaft through the head Fix the bolt to prevent the pin camshaft from coming out Bolt used to prevent the pin camshaft from coming out CHAIN SPRING TENSIONER M6 x 12 BOLT 1 pc Bolt used to prevent the pin camshaft from coming out PIN CAMSHAFT TENSIONER PIN TENSIONER Fig 5 41b 11 MOUNTING THE TENSIONER SPRING TENSIONER TENSIONER PIN TENSIONER Fig 5 42a Fig 5 42b 35 12 BALANCER SHAFT OPTION for EX27 only Mount the balancer shaft on the crankcase align the timing marks on the balancer gear and the crankshaft gear TIMING MARK NOTE Incorrect alignment of the timing marks can result in malfunction of the engine leading to damage due to interference of the parts 13 MAIN BEARING COVER Apply oil to the bearing and the oil seal lip when mounting the main bearing cover Also apply sealant Three Bond

Subaru Robin Power Products 17 Automobile Parts User Manual

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