Subaru Robin Power Products EX21 manual

SERVICE MANU AL EX13,17,21,27 SP170,SP210 EX21 E lectronic Fuel Injection ENGINES Models PUB-ES1934 Rev . 08/09[...]

© Copyright 2009 Robin America, Inc. Robin America, Inc. 905 T elser Road • Lake Zurich, IL 60047 • Phone: 847-540-7300 • Fax: 847-438-5012 e-mail: sales@robinamerica.com • www .subarupower .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 Ai r- Cool ed, 4-Cycle, S lant S ingl e-Cyli nder , Hor iz on t al P . T . O . Sha f t , O HC G as oline E ngin e 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 - 2. PERFORMANCE 2-1 MAXIMUM OUTPUT The Maximum output is the output of an engine with its throttle v alv e fully opened and considering that all the moving par ts are properly broken in. A ne w engine ma y not produce full maxim um output while its moving par ts are still not brok en-in. NO TE : P ow er cur ves shown in the f ollowing charts a[...]

- 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 realiz ed by emplo ying sophisticated OHC system. - Emplo yment of an optimized capacity Rigid Muffler . 3-2 EXTREMEL Y EAS[...]

- 8 - 4-1 CYLINDER AND CRANKCASE The cylinder and cr ankcase are alumin um die-casting as a single piece. A special cast iron cylinder liner is molded into the alumin um die-casting. The crankcase has a mounting surface on the output shaft side to which the main bearing co ver is attached. The cylinder is inclined to the r ight at an angle of 25 de[...]

- 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 e xpander type can be selected as the spa[...]

- 10 - 4-13 IGNITION SYSTEM The ignition system is a tr ansistor controlled magneto system with the ignition timing set at 23 deg rees (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 w orks as a fan) is directly mounted on the crankshaft and the ignition c[...]

- 11 - 4-14 CARBURET OR The engine is equipped with a hor i zontal dr aft carburetor . The carburetor setting is calibrated after careful testing for optimum all-round perf or mance (including star ting, acceleration, fuel consumption, output power characteristics). Special attention is also paid to the gener al-pur pose use of the engine . (F or f[...]

- 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 view – 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 , memor ize the location of each par t so that y ou can reassemb le the engine correctly . If necessar y , attach identification tags with the required assemb ly information to the parts. (2) Store g roups of par ts in separate bo x[...]

- 15 - Step P ar ts to remove Remarks and procedures Fastener s 1 Drain the engine oill (1) Remo ve 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 remove Remarks and procedues Fastener s 12 I gni t i on coi l Remove t he spar k pl ug cap f rom t he spar k pl ug and rem ove the i gni tion co i l from t[...]

- 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 Part 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 ec t 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) Remov e the charge coil. (F or EX27, remove the wire clamp together) bo x spanner M6 × 20mm : 2 pcs . + screwdriv er 18 Spark pl[...]

- 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 a r m Remov e the pin (rock er ar m) and the rocker arm from the cylinder head at the compression top dead cen[...]

- 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 F asteners 25 Connecting rod and piston ( 1 ) Scrape off any 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 p[...]

- 28 - Step Part s to rem ove R emar ks and procedures Fastener s 27 C r a n k sh a ft (1) R emov e the woodruf f key ( for the f lyw heel m agneto) . (2 ) R emove t he cranksha ft f rom t he crankcase by t appi ng its m agnet o si de end w ith a plast i c ham mer , taking car e not t o dam age the oil s e a l .( S e e F i g .5 - 2 4 ) Pl ast i c h[...]

- 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 f or charge coil type. (c ) Mount the control unit. Fix the ear th wire of the control unit at the same time. (See Fig. 5-49a on page 38). Fig.5-29 Fig.5-30 5-4 [...]

- 30 - (3) PIST ON AND PISTON RINGS Install each piston ring in the correct g roove of the piston by widening it enough to slide it o ver the piston. NOTE: Be careful not to twist the r ings too m uch, as the y ma y be damaged. In stall the oil ring first, f ollowed b y the second r ing and then the top ring. When installing the second ring, make s[...]

- 31 - (4) PIST ON AND CONNECTING R OD The piston is attached to the connecting rod b y the piston pin. When assembling the piston and connecting rod, make sure to align the mar k on the piston head with the ‘MA G’ mark on the connecting rod. NO T E 1: Bef ore assembling the connecting rod, apply oil to its small end. NOTE 2 : Be sure to insert[...]

- 32 - ( b ) Rotate the cr ankshaft down to the bottom dead center and lightly tap the piston head until the large end of the connecting rod touches the cr ank pin. (c ) T o mount the connecting rod, line up the matching marks and fit the clinch por 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 cr ankcase . 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 an y scratches on mounting surf ace and replace head gask et to ne w 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 b y inser ting 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 bear ing and the oil seal lip when mounting the main bear ing cover . Also apply sealant (Three Bond ì1215î) to the surf ace of the crankcase. T o av oid damaging the oil seal lip , wr ap the crankshaft ke y-wa y por tion with polyvinyl tape bef ore mounting the main bearing cov er . NO TE: Be care[...]

- 37 - (15) V AL VE CLEARANCE ADJUSTMENT T emporarily fit the flywheel. Rotate the crankshaft up to the compression top dead center and inser t the thic kness gauge between the valve and the adjusting scre w of rock er ar m to measure the clear ance. [Adjustment method] Loosen the n ut on the adjustment scre w and turn the screw to adjust the v alv[...]

- 38 - (16) ROCKER CO VER Replace the gask et with a new 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) B AFFLE 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] M[...]

- 39 - Fig. 5-51 Air gap Fig. 5-52 Fig. 5-53 FLYWHEEL STARTING PULLE Y IGNITION COIL THICKNESS GAUGE To STOP SWITCH (19) FL YWHEEL AND ST ARTING PULLEY NOTE: When mounting the flywheel, be sure to wipe off any oil on the tapered por tion 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 BAFFLE Mount the speed control le v er and brack et, baffle 2 (head) and baffle 3 on the cr ankcase. NO TE : T[...]

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

- 42 - Gov er nor system adjustment method The gov er nor unit is a centrifugal flyweight type and is installed on the go v er nor gear . Since it automatically adjusts the throttle v alve of the carb uretor b y means of a link mechanism, it is possib le to maintain a constant engine speed, e v en with load v ar iations. (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 remove 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. RECOIL STAR[...]

- 45 - Dual element STD T ype Fig. 5-62 (29) AIR CLEANER Mount the air cleaner element and cleaner co v er . (28) STOP SWITCH (1) Mount the stop s witch on the blo wer housing. ( 2 ) Refer to the wir ing diagram (See page 5 1 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 alves and connecting rod should be thoroughly R UN-IN before being put bac k into ser vice. Good bearing surfaces and r unning clearances between the v ar ious par ts can only be estab lished by operating the e[...]

- 47 - 6. ENGINE OIL Using engine oil of the correct gr ade and viscosity greatly lengthens engine lif e and impro ves performance. T oo much or too little oil can also result in ser ious 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 [...]

- 48 - 7. MA GNET O 7-1 MA GNET O The Robin Engine uses a T .I.C. type break er less 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 specializ ed piece of equipment.) As f or the lig[...]

- 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) Rev olution of the flywheel gener ates electricity on the primary side of the ignition coil ( 1) , and the base current I 1 flo ws to the power 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 in a case[...]

- 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 Bat[...]

- 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 BS OFF ON START 8-4 MODEL WITH OIL SENSOR T o LED Lamp Y ellow Y ellow / Red Black Oil sensor control unit Orange [...]

- 53 - 9. ELECTRIC ST ARTER 9-1 SPECIFICA TIONS M odels EX17, 21 M odel EX27 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 switch. The figure below sho ws the state when the star ter is ON. There are two energiz ed circuits: t[...]

- 54 - PINION ST OPPER SET PINION A Y FRONT MET AL CASE MET AL FRONT CO VER 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 vel, the float mo ves 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 (with[...]

- 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 belo w the carb uretor body . Through the operation of the float and the needle v alve, the float chamber maintains a constant fuel le vel while the engine is w or king. The fuel flows from the tank into the float chamber t[...]

- 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 overhauling the carb uretor are described below . (Ref er to Fig. 11-3.) 12-3-1 THRO TTLE SYSTEM (1) When the throttle stop screw is remov ed, the spring can be taken out. (2) Remo ve the phillips screw and the throttle v alve , then tak e out the throttle shaft . When removing the throttle v alve, take care not to damage[...]

- 61 - 13-1-1 DISASSEMBL Y PR OCEDURE (1) Release the reel spring pow e r -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 do wn firmly with both thumbs , taking care not to allow it to spring back. (Fig. 12-1) -4 Remov e the knot from th[...]

- 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 grease to the surf ace 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 w a 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 Pass the rope end through the rope guide and the rope hole of the reel and pull through appro ximately 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 assembled as specified. (b) If the ratchet does not work, check f or missing par ts such as the friction spring. (2) Pull out the star ter knob as f ar as it will[...]

- 66 - 14. INST ALLA TION Installation has a decisiv e influence on engine lif e, ease of maintenance and inspection, frequency of inspection and repair , running costs and other related aspects . Bef ore installing the engine , be sure to plan the installation with care, taking the points belo w into account. 14-1 INST ALLING When installing the e[...]

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

- 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 ignition coil and flywheel Adjust 2. Fuel[...]

- 69 - Prob lem and possible cause Remedy 1. Insufficient compression 1) Loosen spar k plug Retighten; replace gask et 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 Repai[...]

- 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 ARTER 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 re[...]

- 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 runs 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) Remov e and check the star ter . Check or replace the pinion clutch if necessary . (2) Check battery charged state and batter y terminal connection or corrosion for an y abnor mali[...]

- 74 - 16. ST AND ARD REP AIR TABLES “STD” in the follo wing table is the par ts dimension from the brand ne w engine or the spare par ts. Whereas, “Limit” shows the maximum allow ance for the par ts to be used on the engine . If the measurement e xceeds beyond the “Limit”, the par t needs to be replaced and/or repaired. 16-1 ST AND ARD[...]

- 75 - IT E M S T D L im it 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 when t he di f fer ence bet w een ma x. a n d mi n . o f diamet er reac hed to 0. 1 (0. 004). EX17 EX21 67. 000 - 67.019 (2. 6378 - 2.6385) EX27 75. 000 - 75[...]

- 76 - IT E M S T D L im it 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 ri 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 ri n g ( thr ee-piece) EX13 0. 060[...]

- 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 EX1 3 EX17 EX21 EX27 0. 020 - 0.049 (0. 0008 - 0.0019) 0. 2 (0. 0078) * Sm all en d inn er d iam e[...]

- 78 - IT E M S T D L imit CAM SHAF T * Cam peak height ( i nt ake and exhaust ) 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 nne r di amet e r * P i n (c a m sp ro c k e t) o u ter d i a m[...]

- 79 - IT E M S T D L im it V AL VE SPR I NG 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 (1 0.47[...]

- 80 - 16-2 TIGHTENING TORQUE IT E M Ti ght eni ng T orque Nm k g f c m f t l b . Cyl i nder head bolts 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 bol t 17. 0 -19. 0 170 - 190 12. 3 - 13. 7 Con ne ct in g r o[...]

- 81 - 17. MAINTENANCE AND ST ORA GE The maintenance jobs described below apply to correct use of the engine under nor mal conditions. The maintenance inter vals mentioned in this section are not a guar antee that no maintenance is required during those inter v als. F or example , when the engine is used in dusty conditions , the air cleaner should[...]

- 82 - 17-5 INSPECTION AND MAINTENANCE EVER Y 300 HOURS 17-6 INSPECTION AND MAINTENANCE EVER Y 500 TO 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 described in step 16-1 abo ve. (2) Drain fuel from the fuel tank and carb uretor float chamber . (3) T o [...]

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SERVICE INFORMA TION[...]

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CONTENTS Section Title Page 1. SPECIFICATIONS ........................................................... 1 2. DESCRIPTION OF FUEL SYSTEM ............................................. . 2 3. DISASSEMBLY AND REASSEMBLY ............................................ 3 3-1 PREPARATIONS AND PRECAUTIONS . ...................................... 3 3-2 SPECI[...]

- 1 - 1. SPECIFICATIONS Model EX21D Type Air-Cooled, 4-Cycle, Slant Single-Cylinder, Horizontal P.T.O. Shaft, OHC Gasoline Engine Bore & Stroke mm (in.) 67 x 60 (2.64 x 2.36) Piston Displacement ml (cu.in.) 211 (12.87) Compression Ratio 8.5 Continuous Output kW(HP)/r.p.m. 3.2(4.4)/3000 3.7(5.0)/3600 Maximum Output kW(HP)/r.p.m. 5.1(7.0)/4000 Ma[...]

- 2 - 2. DESCRIPTION OF FUEL SYSTEM This engine is equipped with electronic fuel injection. The fuel system consists of a throttle body assembly, power generation module, wire harness, cylinder head air pulse hose, fuel pressure return pipe and a fine mesh fuel filter. The fuel system is calibrated after careful testing for optimum all-round perfor[...]

- 3 - 3. DISASSEMBLY AND REASSEMBLY 3-1 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 reassemb[...]

- 4 - 3-3 DISASSEMBLY PROCEDURES (DIFFERENCE) Step Parts to remove Renarks and procedures Parts Fasteners 7 Fuel tank (1) Drain fuel from the tank. (2) Remove the fuel tank mounting nuts and bolts from the crankcase. (3) Disconnect the fuel pipe from the tank outlet. (See Fig. 3-1) (4) Disconnect the fuel return line from the bottom of the fuel tan[...]

- 5 - Step Parts to remove Renarks and procedures Parts Fasteners 10 Throttle body, Insulator (1) Disconnect the fuel pump pulse line from the throttle body. (2) Leaving the wire harness plugged into the throttle body, disconnect the EFI wire harness from the engine. (3) Remove the harness ground (black) from the top of the crankcase. (4) Disconnec[...]

- 6 - Step Parts to remove Renarks and procedures Parts Fasteners 17 EFI power generation module Remove the EFI power generation modudle. M6 × 20mm : 2 pcs. + screwdriver STEP 17 SCREW AND WASHER AY POWER COIL CP A VIEW A POWER COIL CP[...]

- 7 - 3-4 REASSEMBLY PROCEDURES (DIFFERENCE) (22) THROTTLE BODY (a) Replace the gasket of insulator with a new one and mount the insulator on the cylinder head intake side. (b) Mount the throttle body keeping the wire harness plugged into the throttle body. Re-connect the fuel pump pulse line from the throttle body. Leaving the wire harness plugged[...]

- 8 - 4. WIRING DIAGRAM MODEL WITH EFI Stop switch Power coil Ignition coil Black Throttle body Black Black Red Orange Y ellow Oil sensor T emperrature sensor Throttle bracket Crankcase Spark plug EFI system Fuel injection[...]

- 9 - 5. THROTTLE BODY 5-1 SPECIFICATIONS This engine is equipped with electronic fuel injection. The fuel system consists of a throttle body assembly, power generation module, wire harness, crankcase air pulse hose, fuel pressure return pipe and a fine mesh fuel filter. The fuel system is calibrated after careful testing for optimum all-round perf[...]

- 10 - 5-2-4 POWER GENERATION MODULE The power generation module is installed under the flywheel. This module provides power to the ECU. 5-2-5 WIRE HARNESS The wire harness for the EFI system connects key system components to the ECU. The EFI wire harness contains a temperature sensor that measures engine temperature. The ECU uses this input to adj[...]

( 4 ) With the throttle body installed on the engine: Carefully remove fuel pump pulse line from throttle body pulse pump fitting Do not damage throttle body when removing the pulse hose . Check for excessive oil in the fuel pump pulse hose If excessive oil is found, allow oil to drain from the pulse line and spray a small amount of carburetor clea[...]

- 14 - 6. INSTALLATION 6-1 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 Any detached tank must have a fuel filter in the fuel feed line with at least 30 micron particle filtration with a minimum flow rate of 200ml/30 seconds[...]

- 1 5 - 7. TROUBLESHOOTING If the engine shows any sign of malfunction, the cause should be 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 prese[...]

- 1 6 - Problem and possible cause Remedy Poor output 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 valve and seat contact Repair or replace 6) Valve stem seizur[...]

- 1 7 - Problem and possible cause Remedy Excessive engine oil consumption 1. Oil leakage 1) Loose oil drain plug Tighten 2) Faulty oil drain gasket Replace 3) Loose main bearing cover bolts Tighten 4) Faulty main bearing cover gasket Replace 5) Crankshaft oil seal (front, rear) defect Replace 2. Oil up 1) Faulty piston oil ring Replace 2) Piston r[...]

- 18 - Check engine spark ENGINE WILL NOT START Spark plug improperly gapped, dirty or fouled or defective Wiring damaged Clean, regap or replace as necessary Repair of replace Leaking gaskets at throttle body or spacer (insulator) Poor fuel quality or water in system Replace Flush and/or refill Compression or core component problems Engine does no[...]

- 19 - 8. 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[...]

- 20 - 8-5 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. 8-6 INSPECTION AND MAINTENANCE EVERY 500 TO 600 HOURS (EVERY 6 MONTHS) MAINTENACE ITEMS REASON / REMARKS (1) Remov[...]

- 2 1 - 9. ORGANIZE Most people know that engines will require daily and periodic maintenance, but it’s also important to be aware of the audible and visual signs of unexpected maintenance needs. Operators should also take into consideration working conditions and how they affect engine performance. Proper engine storage shouldn’t be overlooked[...]

- 2 2 - 9-2 ADJUSTING FOR THE ENVIRONMENT In addition to a regular maintenance routine, some application circumstances require special care, such as high altitudes, heat and cold. Altitudes above 5,000 feet may cause engines to start hard and perform poorly. Emissions also are typically higher, and operators may experience trouble with spark plugs.[...]

- 2 3 - 9-3 SUITING UP FOR STORAGE Whether it’s the off-season or other circumstances prevent operating your engine-powered equipment for more than 30 days, special steps need to be taken to protect the engine. The first step in preparing an engine for storage is performing all of the suggested daily maintenance items, such as cleaning the engine[...]

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