Subaru Robin Power Products 17 manual

SERVICE MANU AL EX13, 17, 21, 27 ENGINES Models PUB-ES1934 Rev . 10/05[...]

© Copyright 2005 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[...]

CONTENTS Section Title P age 1. SPECIFICA TIONS ...................................................................................................... 1 2. PERFORMANCE ...................................................................................................... 2 3. FEA TURES ................................................................[...]

- 1 - 1. SPECIFICA TIONS ＊ Specifications are subject to change without notice. M odel EX13 D EX17D EX21D EX27D Ty p e A ir- C ool ed, 4- C ycle, S l ant Si ngle-Cyl inder , Hor iz on t al P . T . O . Sh af t , O HC G aso line Eng ine Bor e & St r oke mm (i n .) 58 x 48 ( 2.28 x 1. 89) 67 x 48 ( 2.64 x 1. 89) 67 x 60 (2 .64 x 2 .3 6 ) 75 x 60[...]

- 2 - 2. PERFORMANCE 2-1 MAXIMUM OUTPUT The Maximum output is the output of an engine with its throttle v alve fully opened and considering that all the moving par ts are properly broken in. A ne w engine ma y not produce full maximum output while its moving par ts are still not broken-in. NO TE : P ower curves sho wn in the following charts are ma[...]

- 3 - 2000 2400 2800 3200 3600 4000 0 0 0.5 1.0 1.0 1.5 2.0 2.0 2.5 3.0 3.0 3.5 4.0 7.0 8.0 9.0 4.0 5.0 kW [HP] r .p.m. REV OLUTION MAXIMUM T ORQUE T ORQUE MAXIMUM HORSEPO WER OUTPUT CONTINUOUS RA TED HP RECOMMENDED HORSEPO WER RANGE 0.7 0.8 0.9 2-4 PERFORMANCE CUR VES EX13D[...]

- 4 - 2000 2400 2800 3200 3600 4000 0 0 0.5 1.0 1.0 1.5 2.0 2.0 2.5 3.0 3.0 3.5 4.0 4.5 12.0 11.0 10.0 9.0 4.0 5.0 6.0 kW [HP] MAXIMUM T ORQUE MAXIMUM HORSEPO WER r .p.m. REV OLUTION T ORQUE OUTPUT CONTINUOUS RA TED HP RECOMMENDED HORSEPO WER RANGE 1.2 1.1 1.0 0.9 EX17D[...]

- 5 - 2000 2400 2800 3200 3600 4000 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 0 1.0 2.0 3.0 4.0 7.0 6.0 5.0 5.5 4.5 12.0 13.0 14.0 15.0 kW [PS] MAXIMUM T ORQUE MAXIMUM HORSEPO WER r .p.m. REV OLUTION T ORQUE OUTPUT CONTINUOUS RA TED HP RECOMMENDED HORSEPO WER RANGE 1.2 1.3 1.4 1.5 EX21D[...]

- 6 - 2000 2400 2800 3200 3600 4000 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 0 1.0 2.0 3.0 4.0 9.0 8.0 7.0 6.0 5.0 6.5 6.0 5.5 4.5 15.0 16.0 17.0 18.0 19.0 7.0 kW [HP] MAXIMUM T ORQUE MAXIMUM HORSEPO WER r .p.m. REV OLUTION T ORQUE OUTPUT CONTINUOUS RA TED HP RECOMMENDED HORSEPO WER RANGE 1.5 1.6 1.7 1.8 1.9 EX27D[...]

- 7 - 3. FEA TURES 3-1 EXTREMEL Y SILENT - SOFT T ONE QU ALITY EX engines are 2dB A quieter and softer in tone than other engines in the same class . This quiet and soft tone is achie v ed by: - A reduction in mechanical noise realized b y emplo ying sophisticated OHC system. - Emplo yment of an optimiz ed capacity Rigid Muffler . 3-2 EXTREMEL Y EA[...]

- 8 - 4-1 CYLINDER AND CRANKCASE The cylinder and crankcase are alumin um die-casting as a single piece. A special cast iron cylinder liner is molded into the aluminum die-casting. The crankcase has a mounting surf ace on the output shaft side to which the main bearing cover is attached. The cylinder is inclined to the right at an angle of 25 deg r[...]

- 9 - 4-5 PIST ON RINGS The piston rings are made of special cast iron. The profile of the top ring is a barrel face or tapered f ace, and that of the second ring is a tapered face. There are 2 types of oil r ing depending on the engine specification. As those are interchangeable , the cutter ring with coil expander type can be selected as the spar[...]

- 10 - 4-13 IGNITION SYSTEM The ignition system is a transistor controlled magneto system with the ignition timing set at 23 degrees (EX13/ 17/21)[27 degrees (EX27)] bef ore the top dead center . The magneto consists of a flywheel and ignition coil. The flywheel (which also works as a f an) is directly mounted on the crankshaft and the ignition coi[...]

- 11 - 4-14 CARBURET OR The engine is equipped with a horizontal draft carburetor . The carburetor setting is calibrated after careful testing f or optimum all-round performance (including star ting, acceleration, fuel consumption, output power characteristics). Special attention is also paid to the general-purpose use of the engine. (F or fur ther[...]

- 12 - Fig. 4-16 TANK CAP FUEL TANK BLOWER HOUSING STARTING PULLEY RECOIL STARTER FLYWHEEL CHARGE COIL (OPTION) OIL SENSOR (OPTION) MAIN BEARING COVER CONNECTING ROD CRANKSHAFT GOVERNOR GEAR GOVERNOR LEVER GOVERNOR SHAFT Cross sectional vie w – across the shaft 4-18 SECTIONAL VIEW OF THE ENGINE[...]

- 13 - Fig. 4-17 FUEL TANK OIL GAUGE OIL DRAIN PLUG TIMING CHAIN FILLER PLUG PISTON PIN PISTON RING CONNECTING ROD STARTING MOTOR (OPTION) M AGNETIC S WITCH MUFFLER PISTON CHAIN GUIDE GOVERNOR LEVER MUFFLER COVER G OVERNOR G EAR FUEL STRAINER TENSIONER OIL SENSOR (OPTION) CRANKSHAFT CRANKCASE ROCKER ARM INTAKE VALVE CAMSHAFT EXHAUST VALVE SPARK ARR[...]

- 14 - Fig. 5-1 5. DISASSEMBL Y AND REASSEMBL Y 5-1 PREP ARA TIONS AND PRECA UTIONS (1) When disassembling the engine , memorize the location of each par t so that you can reassemble the engine correctly . If necessar y , attach identification tags with the required assembly inf ormation to the par ts. (2) Store groups of par ts in separate box es.[...]

- 15 - Step P ar ts to remove Remarks and procedures Fastener s 1 Drain the engine oill (1) Remov e a drain plug (M14×12mm) located on both sides of the case. T ake care not to lose the gask ets. (2) T o discharge oil quickly , remov e the oil guage. 14 mm spanner Fig. 5-2 OIL GAUGE GASKET GASKET DRAIN PLUG STEP 1 5-3 DISASSEMBL Y PROCEDURE[...]

- 16 - Fig. 5-3 Step P ar ts to remove Remarks and pr ocedures Fasteners 2 Air cleaner cov er Remov e the air cleaner cov er . 3 Air cleaner Remov e the element, and remov e the air cleaner while pulling the breather pipe aw ay from the rock er cov er . 10 mm bo x spanner M6 nut: 2 pcs. M 6×2 0: 1p c . M6 x 20 FLANGE BOLT : 1 pc. M6 FLANGE NUT : 2[...]

- 17 - Fig. 5-4 STEP 4 STEP 5 STEP 6 STEP 6 M6 x 8 BOLT : 4 pcs. M6 x 12 BOLT : 4 pcs. STOP SWITCH BAFFLE 2 (HEAD) BAFFLE 3 (EX21 ONLY) M4 TAPPING SCREW : 2 pcs. RECOIL STARTER BLOWER HOUSING M6 x 12 BOLT : 1 pc. M5 TAPPING BOLT : 2 pcs. Step P ar ts to remove Remarks and procedures F asteners 4 Stop s witch Disconnect the wire and remov e the stop[...]

- 18 - A A STEP 7 STEP 8 FUEL TANK M6 x 25 BOLT : 1 pc. (EX13, 17, 21) M8 x 25 BOLT : 2 pcs. (EX27) M6 NUT : 2 pcs. (EX13,17,21) M8 NUT : 2 pcs. (EX27) M8 NUT : 2 pcs. GASKET (It has two faces) M6 x 10 TAPPING BOLT : 2 pcs. M6 x 8 FLANGE BOLT : 1 pc. M8 x 12 BOLT : 1 pc. MUFFLER Seal the exhaust port with adhesive tape or plug it with cloth. FUEL D[...]

- 19 - Fig.5-7 Step P ar ts to remove Remarks and procedures Fasteners 9 Gov er nor system (1) Loosen the bolt and remov e the gov er nor le ver from the gov er nor shaft. There is no need to remov e the bolt. (2) Remov e the gov er nor spr ing. (3) Remov e the gov er nor rod and the rod spring from the carburetor . 10 mm bo x spanner or spanner M6[...]

- 20 - STEP 12 STEP 13 STEP 14 GROMMET (EX13,17,21 only) STARTING PULLEY FLYWHEEL M14 NUT : 1 pc. (EX13,17,21) M18 NUT : 1 pc. (EX27) M6 x 25 BOL T an d W ASHER : 2 pcs. Fig. 5-9 Step Par ts t o r emove Remarks and procedues Fastener s 12 I gni t i on coi l Remove t he spar k pl ug cap f rom the spar k plug and rem ove the i gni tion co i l fr o m [...]

- 21 - ELECTRIC STARTER (option) STEP 15 UPPER SIDE M6 x 30 FLANGE BOLT : 1 pc . DOWN SIDE M6 x 20 FLANGE BOLT : 1 pc . EX17, 21 EX27 M8 x 28 BOLT : 2 pcs. M6 NUT : 1 pc. (EX17,21) M8 NUT : 1 pc. (EX27) Step P art s to rem ove Remarks and procedures Fastener s 15 El ect ric st ar t er (opt i on) Contr ol box, Diod e r ect if ier , Magnet ic sw itch[...]

- 22 - Fig.5-12 Step P ar ts to remove Remarks and procedures Fastener s 16 Baffle 1 (case) Remov e the baffl e 1 (case) M6 × 12mm : 1 pc. (Models EX13, 17 and 21) M8 × 12mm : 1 pc. (Model EX27) 17 Charge coil (option) Remove the charge coil. (F or EX27, remove the wire clamp together) bo x spanner M6 × 20mm : 2 pcs. + screwdriv er 18 Spark plug[...]

- 23 - Fig. 5-14a Step P ar ts to remove Remarks and procedures Fastener s 19 Rock er cov er (1) Remov e the rock er cover from the cylinder head. (2) Remov e the gasket (roc ker cov er). 10 mm bo x spanner M6 × 12mm : 4 pcs. 20 Ro cke r ar m Remove the pin (roc ker arm) and the rocker arm from the cylinder head at the compression top dead center [...]

- 24 - Fig. 5-16 Step P ar ts to remove Remarks and procedures F asteners 21 Main bearing cov er (1) Remov e the flange bolts of main bearing cov er from the crankcase. Remov e the main bearing cover while tapping gently around the cov er using a plastic hammer or similar tool. (See Fig. 5-16) Be careful not to damage the oil gauge or oil seal or n[...]

- 25 - TENSIONER SPRING (TENSIONER) CHAIN PIN (TENSIONER) PIN (CAMSHAFT) CAMSHAFT CHAIN STEP 22 STEP 22 M6 x 12 BOL T : 1 pc. Bolt used to prevent the pin (camshaft) from coming out Fig. 5-17 Fig.5-19 Fig.5-18b CAMSHAFT CHAIN Fig.5-18a PIN (TENSIONER) M6 x 12 BOL T : 1 pc. Bolt used to prevent the pin (camshaft) from coming out PIN (CAMSHAFT) Step [...]

- 26 - Fig.5-20 Fig.5-21 Step P ar ts to remove Remarks and procedures Fastener s 23 Cylinder head, Chain guide (1) Remov e the cylinder head from the crankcase. (2) Remov e the cylinder head gasket from the cylinder head. T ake care not to lose the pipe knocks . (3) Remov e the chain guide from the top side of the crankcase. (If the chain guide is[...]

- 27 - Step P ar ts to remove Remarks and pr ocedures Fastener s 25 Connecting rod and piston ( 1 ) Scrape off an y carbon from the cylinder and the piston head, then remov e the connecting rod bolt. ( 2 ) Remov e the connecting rod cap . ( 3 ) Rotate the crankshaft until the piston comes to its top position. Push the connecting rod and remov e the[...]

- 28 - Step Part s to rem ove R emar ks and p rocedures Fast en ers 27 C r a n ks h a ft (1 ) R em ove the woodr uff key ( for the f lyw heel m agneto) . (2 ) Remove the cr an kshaft fr o m the cr an kcase by t appi ng its m agnet o si de end w ith a plast i c ham mer , t aki ng car e not t o dam age the oil s e a l .( S e e F i g .5 - 2 4 ) Pl ast[...]

- 29 - OIL SENSOR SHIELD PLATE(OS) M6 x 12 BOLT : 1pc. M6 x 16 BOLT : 2pcs. CLAMP (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 . (c ) Mount the control unit. Fix the earth wire of the control unit at the same time. (See Fig. 5-49a on page 38). Fig.5-29 Fig.5-30 5-4 R[...]

- 30 - (3) PISTON AND PIST ON RINGS Install each piston ring in the correct groov e of the piston by widening it enough to slide it o v er the piston. NOTE: Be careful not to twist the r ings too much, as t he y m a y be damaged. I n stall the oil ring first, follo wed by the second ring and then the top ring. When installing the second ring, make [...]

- 31 - (4) PIST ON AND CONNECTING R OD 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 ‘MA G’ mark on the connecting rod. NO T E 1: Before assemb ling the connecting rod, apply oil to its small end. NOTE 2 : Be sure to inser t [...]

- 32 - ( b ) Rotate the crankshaft do wn to the bottom dead center and lightly tap the piston head until the large end of the connecting rod touches the crank pin. (c ) T o mount the connecting rod, line up the matching marks and fit the clinch p or tions fir mly together . Fig. 5-37 A LIGNMENT M ARKS ALIGNMEN T MARKS (d) Check f or free mov ement [...]

- 33 - (7) CHAIN GUIDE Mount the chain guide to the crankcase . Fig. 5-39b Model EX21 mounting position Models EX13, 17 and 27 mounting positions CHAIN GUIDE Fig. 5-39a (8) CYLINDER HEAD Inspect and repair any scratches on mounting surf ace and replace head gask et to new one bef ore installing. Tighten the cylinder head bolts in diagonal order . ([...]

- 34 - TIMING MARK The position of top dead center MARK PLATE MARK PLATE MARK PLATE MARK PLATE MARK PLATE MARK PLATE TIMING MARK ROLL PIN ROLL PIN ROLL PIN TIMING MARK TIMING MARK TIMING MARK TIMING MARK CHAIN GUIDE FITTING POSITION CHAIN GUIDE FITTING POSITION CHAIN GUIDE FITTING POSITION The mark plate does not have a camshaft side or crankshaft [...]

- 35 - TENSIONER S PRING ( TENSIONER) CHAIN PIN(TENSIONER) PIN(CAMSHAFT) CAMSHAFT CHAIN M6 x 12 BOL T : 1 pc. Bolt used to prevent the pin (camshaft) from coming out Fig. 5-42b (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 pre v ent the pin ([...]

- 36 - (13) MAIN BEARING CO VER Apply oil to the bearing and the oil seal lip when mounting the main bear ing cov er . Also apply sealant (Three Bond “1215”) to the surface of the cr ankcase. T o avoid damaging the oil seal lip , wr ap the crankshaft ke y-w a y por tion with polyvinyl tape bef ore mounting the main bearing cov er . NO TE: Be ca[...]

- 37 - (15) V A L VE CLEARANCE ADJUSTMENT T emporarily fit the flywheel. Rotate the crankshaft up to the compression top dead center and inser t the thickness gauge between the v alve and the adjusting scre w of rock er ar m to measure the clearance. [Adjustment method] Loosen the nut on the adjustment scre w and tur n the screw to adjust the v alv[...]

- 38 - (16) ROCKER CO VER Replace the gasket with a ne w one, and mount the rock er cov er . M6 ✕ 12mm flange bolt : 4 pcs. SPARK PLUG ROCKER COVER M6 x 12 BOLT : 4 pcs. GASKET (ROCKER COVER) (18) BAFFLE 1 (CASE) Align the top and bottom of the baffle 1 (case) with the crankcase and mount it with the bolts . [ Model without electric star ter] M6 [...]

- 39 - Fig. 5-51 Air gap Fig. 5-52 Fig. 5-53 FLYWHEEL STARTING PULLE Y IGNITION COIL THICKNESS GAUGE To STO P SWITCH (19) FL YWHEEL AND ST ARTING 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 st[...]

- 40 - Fig. 5-54 M6 x 12 BOLT : 2 pcs. M6 x 12 BOLT : 1 pce. SPEED CONTROL LEVER and BRACKET CARBURATOR BAFFLE 2 (HEAD) BAFFLE 3 (EX21 ONLY) M5 TAPPING BOLT : 2 pcs. INSULATOR A Detail A GASKET GASKET (21) SPEED CONTROL LEVER, BRA CKET AND B AFFLE Mount the speed control le v er and brac k et, baffle 2 (head) and baffle 3 on the cr ankcase . NO TE [...]

- 41 - (23) GO VERNOR LEVER (a) P ass the governor rod through the rod spring, then connect to the throttle lev er of the carburetor . (b) Attach the gov er nor rod and rod spring to the gov er nor le ver , then mount the go vernor le ver on the go vernor shaft. Do not adjust the bolt on the go ver nor le ver y et. (c) Connect the governor lev er a[...]

- 42 - ■ Gov ernor system adjustment method The gov er nor unit is a centrifugal flyweight type and is installed on the gov ernor gear . Since it automatically adjusts the throttle v alv e of the carburetor b y means of a link mechanism, it is possib le to maintain a constant engine speed, e v en with load v ariations. (1) T ur n the speed contro[...]

- 43 - (25) MUFFLER (1) Mount the muffler and the gask et on the cylinder head. (2) Mount the muffler cov er on the muffler . M6 ✕ 8 mm flange bolt : 1 pc. M6 ✕ 10 mm tapping bolt : 2 pcs . NO TE : Be sure to remov e an y tape or cloth used to cov er the e xhaust por t when the engine was disassemb led . M8 ✕ 12 mm bolt : 1 pc. M8 nut : 2 pcs[...]

- 44 - Fig. 5-60 (27) BLO WER HOUSING AND RECOIL ST ARTER (1) Mount the ignition coil cord on the crankcase by aligning it with the baffle 1 (case). (2) Mount the blo wer housing on the crankcase. M6 × 12 mm bolt : 4 pcs. (3) Mount the recoil star ter on the blow er housing. M6 × 8 mm bolt : 4 pcs. M6 x 8 BOLT : 4 pcs. M6 x 12 BOLT : 4 pcs. RECOI[...]

- 45 - Dual element STD T ype Fig. 5-62 (29) AIR CLEANER Mount the air cleaner element and cleaner cov er . (28) STOP SWITCH (1) Mount the stop switch on the b lo wer housing. ( 2 ) Ref er to the wir ing diagram (See page 51 and 52 ) f or wiring details. Fig. 5-61 STOP SWITCH[...]

- 46 - (32) BREAK-IN OPERA TION A ne w engine or an engine that has been completely overhauled b y being fitted with a new piston, rings, v alv es and connecting rod should be thoroughly R UN-IN bef ore being put bac k into ser vice. Good bearing surfaces and running clearances betw een the various par ts can only be established by oper ating the e[...]

- 47 - 6. ENGINE OIL Using engine oil of the correct grade and viscosity greatly lengthens engine lif e and impro ves perf ormance. T oo much or too little oil can also result in serious problems , including engine seizure . 6-1 CLASSIFICA TION BY OIL GRADE API (American P etroleum Institute) 6-2 CLASSIFICA TION BY OIL VISCOSITY SAE (Society of A u[...]

- 48 - 7. MA GNET O 7-1 MA GNET O The Robin Engine uses a T .I.C . type breakerless magneto ignition system. (1) T .I.C . (TRANSISTOR IGNITER CIRCUIT) has the ignition coil outside the flywheel, which is the standard specification. A charge coil system is a v ailable as an option. (The flywheel is a specialized piece of equipment.) As f or the ligh[...]

- 49 - 7-3 IGNITION SYSTEM (EX13 ,17, 21) 7-3-1 TYPE OF IGNITION SYSTEM EX13, 17 and EX21 hav e the T .I.C . (T ransister , Igniter , Circuit) pointless ignition system. As optional par ts, these ignition system ma y be implemented with lamp coil, charge coil and excitor coil. LowSpeed Ignition Timing Control Circuit Automatic Advancing Control Cir[...]

- 50 - 7-4-3 B ASIC THEOR Y (a) Re volution of the flywheel gener ates electricity on the pr imar y side of the ignition coil ( ① ), and the base current I 1 flo ws to the po w er transistor ( ② ). Current I 1 turns the power transistor “ON” and the electric current I 2 flows. This is the same situation when the contact break er is closed i[...]

- 51 - Stop switch Flywheel Ignition coil (with built-in transistor) Black Spark plug 8. WIRING DIA GRAM 8-1 MODEL WITHOUT ELECTRIC ST ARTER (Models EX13, 17, 21 and 27) 8-2 MODEL WITH ELECTRIC ST ARTER (Models EX17 and 21) Fig. 8 -1 Fig. 8 -2 +M - M ST B LA106 LA406 LA306 Black Red Charge coil Diode rectifier Ignition coil Spark plug Ke y switch B[...]

- 52 - 8-3 MODEL WITH ELECTRIC ST ARTER (Model EX27) Fig. 8 -3 +M - M ST B LA108 LA408 Black Red Charge coil Diode rectifier Ignition coil Spark plug Ke y switch Battery (12V24AH) Electric starter M agneto Ke y switch 066-00003-30 -M +M B S OFF ON START 8-4 MODEL WITH OIL SENSOR T o LED Lamp Y ello w Y ello w / Red Black Oil sensor control unit Ora[...]

- 53 - 9. ELECTRIC ST ARTER 9-1 SPECIFICA TIONS M odels EX17, 21 M odel EX 27 V ol t age (V) 12 Po w e r ( k W ) 0 .6 0 .6 Weight (kg) 1. 6 3. 4 9-2 OPERA TING PRINCIPLES The batter y is connected to the 6 or 8 mm diameter ter minal of the magnetic s witch. The figure below sho ws the state when the star ter is ON. There are two energiz ed circuits[...]

- 54 - PINION ST OPPER SET PINION A Y FRONT MET AL CASE MET AL FR ONT COVER ARMA TURE A Y Y OKE A Y THROUGH BOL T (2 pcs.) BRUSH HOLDER BRUSH SPRING (BRUSH) REAR CO VER MA GNETIC SWITCH PINION A Y FRONT CO VER BA TTER Y CABLE ARMA TURE A Y Y OKE A Y O - RING O - RING THROUGH BOL T (2 pcs .) W ASHER SPRING (BRUSH) REAR CO VER BRUSH HOLDER BRUSH MA G[...]

- 55 - 10. OIL SENSOR 10-1 SPECIFICA TIONS 10-2 CONSTRUCTION AND OPERA TION The oil sensor is composed of the float, per manent magnet incor porated into the float and the oil sensor . In accordance with the oil le v el, the float mov es up and down. When the oil le vel is upper le vel, the float mo ves up . Fig.10-1 OIL SENSOR Type Float type (wit[...]

- 56 - A A ROCKER ARM (EXHAUST) ROCKER ARM (EXHAUST) ROCKER ARM (INTAKE) CAM CRESCENT CAM RELEASE LEVER RELEASE LEVER ROCKER ARM (EXHAUST) ROCKER ARM (INTAKE) CAM CRESCENT CAM CAMSHAFT ROCKER ARM (EXHAUST) CAMSHAFT RELEASE LEVER RELEASE LEVER DETAIL A DETAIL A Fig. 11-2 11. A UT OMA TIC DECOMPRESSION SYSTEM 11-1 FUNCTIONS AND CONSTRUCTION EX series[...]

- 57 - 12. CARBURET OR 12-1 SPECIFICA TIONS 12-2 FUNCTIONS AND CONSTRUCTION 12-2-1 FLO A T SYSTEM The float chamber is located below the carb uretor body . Through the oper ation of the float and the needle v alv e , the float chamber maintains a constant fuel le v el while the engine is w orking. The fuel flows from the tank into the float chamber[...]

- 58 - PILO T OUTLET BYP ASS PILO T AIR JET CHOKE V AL VE AIR INT AKE PORT MAIN AIR JET MAIN NOZZLE FLO A T CHAMBER PILO T JET FLO A T MAIN JET FUEL NEEDLE VA LV E FLO A T Fig. 12-2 Fig. 12-1 FUEL SYSTEM OUTLINE[...]

- 59 - Fig. 12-3 MODEL EX13, 17, 21 MODEL EX27 1 22 23 3 5 11 9 8 4 10 12 1 3 2 1 4 24 28 18 16 17 25 26 21 6 7 19 20 27 13 14 21 18 20 25 26 3 5 9 8 4 22 23 1 11 12 24 10 6 7 12-3 DISASSEMBL Y AND REASSEMBL Y Mechanical f ailures aside, most carburetor malfunctions occur when the fuel/air r atio of the mixture is not correct. This is usually cause[...]

- 60 - The procedures f or o v erhauling the carb uretor are described below . (Refer to Fig. 11-3.) 12-3-1 THRO TTLE SYSTEM (1) When the throttle stop scre w is remov ed, the spring can be taken out. (2) Remo ve the phillips screw and the throttle valv e , then tak e out the throttle shaft . When removing the throttle v alve, tak e care not to dam[...]

- 61 - 13-1-1 DISASSEMBL Y PROCEDURE (1) Release the reel spr ing power -1 Hold the star ter knob and pull out the star ter rope. -2 Pull out the rope fully and align the rope knot in the reel with the rope guide. - 3 Hold the reel down fir mly with both thumbs, taking care not to allow it to spring back. (Fig. 12-1) -4 Remov e the knot from the re[...]

- 62 - GREASE SHAFT HOOK Position where the inner end of the spring touches to the rib of the bearing . 13-1-2 REASSEMBL Y PROCEDURE (1) Put the reel back into the case - 1 Apply g rease t o 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 wa y that the in[...]

- 63 - (2) Mount the components -1 Mount the ratchet into the reel. (Fig. 13-5) -2 Mount the ratchet guide assembly , taking care not to mov e the ratchet. (Fig.13-6) (3) Tighten the set scre w -1 Hold the ratchet guide gently by your hand to pre vent it from rotating, then tighten the set screw . Fig. 13-5 Fig. 13-6 Fig. 13-7 NO TE: The spring for[...]

- 64 - (5) Install the rope NO TE: This procedure requires 2 people. - 1 P ass 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) -3 Put the rope into the reel, taking care that the rope end does not stick up . (Fig. 13-9) - [...]

- 65 - 13-1-3 CHECKING THE RECOIL ST ARTER AFTER REASSEMBL Y (1) Pull the star ter knob about 2-3 times. (a) If the star ter knob is too hea vy to pull, chec k that each par ts hav e been assemb led as specified. (b) If the ratchet does not work, check f or missing par ts such as the fr iction spring. (2) Pull out the star ter knob as f ar as it wi[...]

- 66 - 14. INST ALLA TION Installation has a decisive influence on engine lif e, 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 INST ALLING When installing the engin[...]

- 67 - 14-5 PO WER TRANSMISSION T O DRIVE MA CHINES 14-5-1 BEL T DRIVE Note the f ollo wing: • Use a V -belt rather than a flat belt. • The drive shaft of the engine m ust be par allel to the drive shaft of the driv en machine . • The drive pulle y of the engine must be in line with the driven pulle y of the machine . • Install the engine p[...]

- 68 - Prob lem and possible cause Remedy 1. Ignition system problems 1) Spark plug  ・ Improper spark plug gap  ・ Insulation def ect  ・ Carbon deposits Adjust the gap Replace Clean 2) Ignition coil  ・ Insulation def ect or discontinuity  ・ P oor contact or broken wire Replace Repair or replace 3 ) Improper air gap between igniti[...]

- 69 - Prob lem and possible cause Remedy 1. Insufficient compression 1) Loosen spark plug Retighten; replace gasket 2) Leakage from cylinder head gasket Retighten; replace gasket 3) Piston ring seizure or wear Replace 4) Piston or cylinder wear Repair or replace 5) Incorrect valv e and seat contact Repair or replace 6) V alv e stem seizure Repair [...]

- 70 - Prob lem and possible cause Remed y 1. Oil leakage 1) Loose oil drain plug Tighten 2) F aulty oil drain gask et Replace 3) Loose main bearing cov er bolts Tighten 4) F aulty main bearing cov er gasket Replace 5) Crankshaft oil seal (front, rear) def ect Replace 2. Oil up 1) F aulty piston oil ring Replace 2) Piston r ing seizure, w ear or po[...]

- 71 - OK Does the crank run? Does the star ter run? E LECTRIC ST AR TER Check battery charged state and batter y terminal connection or corrosion f or any abnor mality . Operation sound of magnetic s witch of star ter With star ter alone, connect the batter y (+) terminal and the M or K terminal of the star ter and check if motor runs. Charge or r[...]

- 72 - (1) Star ter does not run or only “click” sound is heard. Problem and chec k item Description Remedy 1. Checking of continuity of wiring Check S terminal and B ter minal for def ormation, looseness, rusting, or dust sticking. Carefully check inserting method of the S terminal. If not abnor mal, set the key switch to ST ART position while[...]

- 73 - (2) Star ter r uns but engine not Problem and chec k item Description Remedy Check engaged state of pinion and ring gear . Motor idles and engine does not run. (1) Remove and chec k the star ter. Check or replace the pinion clutch if necessary . (2) Check battery charged state and batter y ter minal connection or corrosion for an y abnor mal[...]

- 74 - 16. ST AND ARD REP AIR TABLES “STD” in the follo wing table is the par ts dimension from the brand new engine or the spare parts. Whereas, “Limit” sho ws the maxim um allo w ance f or the par ts to be used on the engine. If the measurement e xceeds be yond the “Limit”, the part needs to be replaced and/or repaired. 16-1 ST AND AR[...]

- 75 - IT E M S T D L imit CYL I NDER * I nner di amet er * R oundness aft er r eboring * C yli ndricity af ter r ebor i ng Standar d EX13 58. 000 - 58. 019 (2. 2835 - 2.2842) T o be rebor ed w hen t he di f fer ence bet w een ma x. a n d mi n . o f diamet er reached t o 0. 1 (0. 004). EX17 EX21 67. 000 - 67. 019 (2. 6378 - 2.6385) EX27 75. 000 - 7[...]

- 76 - IT E M S T D L imit PI ST O N * Ring groove side clearance To p Sec ond EX13 EX17 EX21 EX27 0. 035 - 0. 080 (0. 0014 - 0.0031) 0. 15 (0. 0059) Oi l r i n g Coil e xp EX13 0. 02 - 0. 075 (0. 0008 - 0.0031) 0. 15 (0. 0059) EX17 EX21 0. 01 - 0. 065 (0. 0004 - 0.0026) EX27 0. 01 - 0. 065 (0. 0004 - 0.0026) Oi l r i n g ( thr ee-piece) EX13 0. 06[...]

- 77 - IT E M S T D L im it CO NNECT I NG RO D * Lar ge end inner diamet er EX13 EX17 EX21 30. 000 - 30.016 (1. 1811 - 1.1817) 30. 1 (1. 1850) EX27 34. 500 - 34. 516 (1. 3386 - 1.3392) 34. 1 (1. 3425) * Cl earance bet w een l ar ge end and cr ank pi n EX13 EX17 EX21 EX27 0. 020 - 0.049 (0. 0008 - 0.0019) 0. 2 (0. 0078) * Sm all en d inn er d iam et[...]

- 78 - IT E M S T D L imit CAM SHAF T * Cam peak heig ht (intake and ex haust) Cam peak height EX13 EX17 EX21 EX27 29. 028 - 29.128 (1. 1428 - 1.1468) 28. 98 (1. 1409) Cam i nner diamet er D 1 ,D 2 EX13 EX17 EX21 EX27 9. 0 - 9.036 (0. 3543 - 0.3557 ) 9. 05 (0. 3563) * C am sprocket i nner d i amet er * P i n (ca m s pro c k e t) ou te r d i ame te [...]

- 79 - IT E M S T D L im it V AL VE SPRI N G FREE LENG TH EX13 EX17 EX21 EX27 27. 4 (1. 0787) V AL VE SEA T AN G LE ( I NT AKE AND EXHA UST) * V alve cu t ter an gl e (a) * V a l ve contact w i dth (b) In ta k e Exhaust EX13 EX17 EX21 EX27 a: 90 ° b: 0.7 - 1.0 (0. 0276 - 0.0394) 2. 0 (0. 0787) CHAI N L ENG TH EX13 263. 1 (10. 3583) 266. 0 (10. 472[...]

- 80 - 16-2 TIGHTENING TORQUE IT E M Ti ght eni ng T orque N ・ mk g f ・ cm f t ・ lb . Cyl i nder head bol ts M 8×6 8f l a n g eb o l t Re-use 25.0 - 27. 0 250 -270 18.1 - 19. 5 When r epl ace t o new cyli nder head and f l ange bol t s 28. 0 - 30.0 280 - 300 20. 3 - 21.7 M 8 × 35 f l ange bolt 17. 0 - 19.0 170 - 190 12. 3 - 13. 7 Con ne ct [...]

- 81 - 17. MAINTENANCE AND ST ORA GE The maintenance jobs described below apply to correct use of the engine under normal conditions. The maintenance inter vals mentioned in this section are not a guar antee that no maintenance is required during those inter vals. F or example , when the engine is used in dusty conditions, the air cleaner should be[...]

- 82 - 17-5 INSPECTION AND MAINTENANCE EVER Y 300 HOURS 17-6 INSPECTION AND MAINTENANCE EVER Y 500 T O 600 HOURS (EVER Y 6 MONTHS) 17-7 MAINTENANCE EVER Y 1,000 HOURS (ANNU AL MAINTENANCE) 17-8 ENGINE ST ORA GE (1) Carry out the maintenance jobs descr ibed in step 16-1 abov e . (2) Drain fuel from the fuel tank and carb uretor float chamber . (3) T[...]

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