Subaru EX13 Service Manual
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Subaru EX13 Service Manual

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SERVICE
MANUAL
Models
EX13,17,21,27
SP170,SP210
EX21
ENGINES
Electronic Fuel Injection
PUB-ES1934
Rev. 08/09

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Summary of Contents for Subaru EX13

  • Page 1 SERVICE MANUAL Models EX13,17,21,27 SP170,SP210 EX21 Electronic Fuel Injection ENGINES PUB-ES1934 Rev. 08/09...
  • Page 2 Robin America, Inc. 905 Telser Road • Lake Zurich, IL 60047 • Phone: 847-540-7300 • Fax: 847-438-5012 © Copyright 2009 Robin America, Inc. e-mail: sales@robinamerica.com • www.subarupower.com...

  • Page 3: Table Of Contents

    CONTENTS Section Title Page 1. SPECIFICATIONS ...................... 1 2. PERFORMANCE ...................... 2 3. FEATURES ....................... 7 4. GENERAL DESCRIPTION OF ENGINE COMPONENTS ........8 5. DISASSEMBLY AND REASSEMBLY ..............14 5-1 PREPARATIONS AND PRECAUTIONS ............14 5-2 SPECIAL TOOLS ....................14 5-3 DISASSEMBLY PROCEDURE ................

  • Page 4: Specifications

    1. SPECIFICATIONS Model EX13D EX17D EX21D EX27D Air-Cooled, 4-Cycle, Slant Single-Cylinder, Type Horizontal P.T.O. Shaft, OHC Gasoline Engine 58 x 48 67 x 48 67 x 60 75 x 60 Bore & Stroke (in.) (2.28 x 1.89) (2.64 x 1.89) (2.64 x 2.36) (2.95 x 2.36) Piston Displacement...

  • Page 5: Performance

    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 following charts are made in conformity with SAE internal combustion engine standard test code J1349.
  • Page 6 2-4 PERFORMANCE CURVES EX13D MAXIMUM TORQUE [HP] MAXIMUM HORSEPOWER CONTINUOUS RATED HP RECOMMENDED HORSEPOWER RANGE 2000 2400 2800 3200 3600 4000 REVOLUTION r.p.m. - 3 -...
  • Page 7 EX17D 12.0 11.0 10.0 MAXIMUM TORQUE [HP] MAXIMUM HORSEPOWER CONTINUOUS RATED HP RECOMMENDED HORSEPOWER RANGE 2000 2400 2800 3200 3600 4000 REVOLUTION r.p.m. - 4 -...
  • Page 8 EX21D 15.0 14.0 13.0 MAXIMUM TORQUE 12.0 [PS] MAXIMUM HORSEPOWER CONTINUOUS RATED HP RECOMMENDED HORSEPOWER RANGE 2000 2400 2800 3200 3600 4000 REVOLUTION r.p.m. - 5 -...
  • Page 9 EX27D 19.0 18.0 17.0 MAXIMUM TORQUE 16.0 15.0 [HP] MAXIMUM HORSEPOWER CONTINUOUS RATED HP RECOMMENDED HORSEPOWER RANGE 2000 2400 2800 3200 3600 4000 REVOLUTION r.p.m. - 6 -...

  • Page 10: Features

    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 EX13, EX17 and EX21, in such as Chain Guide, Air Cleaner, Ignition Coil, etc.

  • Page 11: General Description Of Engine Components

    4. GENERAL DESCRIPTION OF ENGINE COMPONENTS 4-1 CYLINDER AND CRANKCASE The cylinder 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.
  • Page 12 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 (EX13/27) RING TAPER...
  • Page 13 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)] before the top dead center. The magneto consists of a flywheel and ignition coil.
  • Page 14 4-14 CARBURETOR The engine is equipped with a 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.
  • Page 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.
  • Page 16 Cross sectional view – along the shaft FUEL STRAINER PISTON MUFFLER MUFFLER COVER GOVERNOR LEVER CHAIN GUIDE EXHAUST VALVE TAIL SCREEN or DEFLECTOR FUEL TANK (OPTION) SPARK GOVERNOR ARRESTER GEAR (OPTION) MAGNETIC ROCKER SWITCH CAMSHAFT INTAKE VALVE TIMING PISTON PIN CHAIN PISTON RING STARTING...

  • Page 17: Disassembly And Reassembly

    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.

  • Page 18: Disassembly Procedure

    5-3 DISASSEMBLY PROCEDURE Step Parts to remove Remarks and procedures Fasteners Drain the engine oill (1) Remove a drain plug (M14×12mm) 14 mm spanner located on both sides of the case. Take care not to lose the gaskets. (2) To discharge oil quickly, remove the oil guage.
  • Page 19 Step Parts to remove Remarks and procedures Fasteners Air cleaner cover Remove the air cleaner cover. Air cleaner Remove the element, and remove the air 10 mm box spanner cleaner while pulling the breather pipe away M6 nut: 2 pcs. from the rocker cover.
  • Page 20 Step 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 × 8mm : 4 pcs. Blower housing (1)Remove the blower housing from the 10 mm box spanner...
  • Page 21 M6 nut : 2 pcs. (3) Disconnect the fuel pipe from the carburetor. (Models EX13, 17 and 21) (See Fig. 5-6) M8 nut : 2 pcs. (Model EX 27) (4) Remove the fuel tank from the crankcase.
  • Page 22 Step Parts to remove Fasteners Remarks and procedures Governor system (1) Loosen the bolt and remove the governor 10 mm box spanner or lever from the governor shaft. There is no spanner need to remove the bolt. M6 × 30mm : 1 pc. (2) Remove the governor spring.
  • Page 23 (Knock the center bolt with a hammer sometimes) ATTACH NUT TEMPORARILY FLYWHEEL PULLER Fig. 5-10 Fig. 5-11 M14 NUT : 1 pc. (EX13,17,21) M18 NUT : 1 pc. (EX27) STARTING PULLEY FLYWHEEL M6 x 25 BOLT and WASHER : 2 pcs.
  • Page 24 Step 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 Magnetic switch (3) Disconnect the wire that connects the M8 nuts...
  • Page 25 Spark plug Remove the spark plug from the cylinder head. 21 mm plug wrench M6 x 12 FLANGE BOLT : 1 pc. (EX13, 17, 21) M8 x 12 FLANGE BOLT : 1 pc. (EX27) For the model without electric starter.
  • Page 26 Step Parts to remove Remarks and procedures Fasteners Rocker cover (1) Remove the rocker cover from the 10 mm box spanner cylinder head. M6 × 12mm : 4 pcs. (2) Remove the gasket (rocker cover). Rocker arm Remove the pin (rocker arm) and the rocker arm from the cylinder head at the compression top dead center.
  • Page 27 12 mm box spanner cover from the crankcase. M8 × 35mm : 6 pcs. Remove the main bearing cover while (Models EX13, 17 and 21) tapping gently around the cover using M8 × 35mm : 7 pcs. a plastic hammer or similar tool.
  • Page 28 Step 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 × 12mm : 1 pc. (2) Remove the retaining bolt of pin (camshaft) from the cylinder head.
  • Page 29 Step Parts to remove Remarks and procedures Fasteners Cylinder head, (1) Remove the cylinder head from the 12 mm box spanner Chain guide crankcase. M8 × 68mm : 4 pcs. (2) Remove the cylinder head gasket from the M8 × 35mm : 1 pc. cylinder head.
  • Page 30 Take special care not to damage the rings when doing this. PISTON RING CONNECTING ROD CAP CLIP CONNECTING ROD PISTON PISTON PIN CLIP M6 x 33 (EX13, 17, 21) M7 x 40 (EX27) CONNECTING ROD BOLT : 2 pcs. Fig.5-22 - 27 -...
  • Page 31 Step 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.

  • Page 32: Reassembly Procedure

    5-4 REASSEMBLY PROCEDURE 5-4-1 NOTES ON 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.
  • Page 33 When installing the second ring, make sure that the ‘N’ mark is face up. (See Fig. 5-33) Fig.5-31 BARREL (EX13/27) RING TAPER (EX17/21) SECOND TAPER RING CUTTER RING...
  • Page 34 (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. When assembling the NOTE 1: Before assembling the connecting rod, piston and connecting...
  • Page 35 ALIGNMENT Tightening torque ALIGNMENT MARKS MARKS EX13,17,21 EX27 0 - 15.0 N ・ m 17.0 - 20.0 N ・ m (130 - 150 kgf・ cm) (170 - 200 kgf・ cm) (9.4 - 10.8 ft・ lb.) ( 12.3 - 1 4 .
  • Page 36 (7) CHAIN GUIDE CHAIN GUIDE Mount the chain guide to the crankcase. Model EX21 mounting position Models EX13, 17 and 27 mounting positions Fig. 5-39b Fig. 5-39a (8) CYLINDER HEAD Inspect and repair any scratches on mounting surface and replace head gasket to new one before installing.
  • Page 37 Model EX13 EX17 EX21 EX27 Number of oval steel link CHAIN GUIDE FITTING POSITION MARK PLATE Model EX13 The mark plate does not have a camshaft side or crankshaft sprocket side. The position of top dead center TIMING MARK ROLL PIN...
  • Page 38 (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. PIN (CAMSHAFT) CHAIN M6 x 12 BOLT : 1 pc. Bolt used to prevent the pin (camshaft) from coming out CAMSHAFT...
  • Page 39 (220 - 240 kgf ・ cm) (16.2 - 17.7 ft・lb.) GOVERNOR SHAFT CRANKSHAFT M8 x 35 BOLT : 6 pcs. (EX13, 17, 21) M8 x 35 BOLT : 7 pcs. (EX27) SEALANT ( Three bond "1215" ) MAIN BEARING COVER Fig.
  • Page 40 (INTAKE VALVE SIDE) compression top dead center by checking Fig. 5-45 mutual position between the flywheel and EX13, 17, 21 the ignition coil or by checking that the key way is at the top. (See each Fig.5-46) The position of...
  • Page 41 [ Model without electric starter] Mount the electric starter and the charging coil, referring to the illustrations of disassembly. 12 mm bolt : 1 pc. (Models EX13, 17 and 21) Tightening torque 12 mm bolt : 1 pc. (Model EX27) EX13, 17, 21 EX27 4.0 N ・m...
  • Page 42 64.0 N ・ m 59.0 Fig. 5-50 640 kgf ・ cm) 42.7 46.3 ft・ lb.) M14 nut : 1 pc. (EX13, 17, 21) M18 nut : 1 pc. (EX27) Fig. 5-51 THICKNESS GAUGE (20) IGNITION COIL When mounting the ignition coil, insert a thickness gauge between the ignition coil and the flywheel to check the air gap.
  • Page 43 (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.
  • Page 44 Discrimination according to the dimensions: EX13, 17 / 50Hz EX21, 27 / 50Hz Color : Gold Color : Gold (Speed con. side) (Governor lever side) EX13, 17, 21, 27 / 60Hz (STD) Color : Silver GOVERNOR ROD and ROD SPRING GOVERNOR GOVERNOR SPRING LEVER...
  • Page 45 (24) AIR CLEANER BASE M6 x 20 FLANGE BOLT : 1 pc. Insert the breather pipe into the rocker cover AIR CLEANER BASE and then mount the air cleaner base. M6 flange nut : 2 pcs. M6 x 20 mm flange bolt : 1 pc. Tightening torque 8.0 N ・...
  • Page 46 M6 x 25 BOLT : 1pc. Model EX13 EX17 EX21 EX27 (EX13, 17, 25) Fuel pipe length M8 x 25 BOLT : 2pcs. 145(5.7) 150(5.9) 155(6.1) 195(7.7) mm(in.) (EX27) NOTE : Make sure the fuel pipe is located on the boss, Fig.
  • Page 47 (3) Mount the fuel tank on the crankcase. FUEL PIPE M6 nut : 2 pcs. 25 mm bolt : 1 pc. (Models EX13, 17 and 21) 25 mm bolt : 2 pcs. (Model EX27) BOSS 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).
  • Page 48 (28) STOP SWITCH STOP SWITCH (1) Mount the stop switch on 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. Type Dual element Fig.
  • Page 49 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 0.6 L 1.0L...

  • Page 50: Engine Oil

    6. ENGINE OIL Using engine oil of the correct grade and viscosity greatly lengthens engine life and 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) Classification Grades suited for Robin Engine: SE or higher (SG,SH or SJ in recomended) 6-2 CLASSIFICATION BY OIL VISCOSITY...

  • Page 51: Magneto

    7. MAGNETO 7-1 MAGNETO 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 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.
  • Page 52 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.
  • Page 53 7-4 IGNITION SYSTEM (EX27) 7-4-1 IGNITION COIL INTERNAL CIRCUIT Base Resister Low Speed Ignition Timing Control Circuit Advancing Control Circuit Fig.7-2a 7-4-2 IGNITION TIMING CHARACTERISTIC LINEAR ADVANCING 1000 1500 2000 2500 3000 3500 4000 ENGINE REVOLUTION (R.P.M.) Fig.7-2b 7-4-3 BASIC THEORY (a) Revolution of the flywheel generates electricity on the primary side of the ignition coil ( ①...

  • Page 54: Wiring Diagram

    8. WIRING DIAGRAM 8-1 MODEL WITHOUT ELECTRIC STARTER (Models EX13, 17, 21 and 27) Spark plug Black Ignition coil (with built-in transistor) Flywheel Fig. 8-1 8-2 MODEL WITH ELECTRIC STARTER (Models EX17 and 21) Spark plug Black Magneto Ignition coil...
  • Page 55 8-3 MODEL WITH ELECTRIC STARTER (Model EX27) Spark plug Black Magneto Ignition coil Key switch Charge coil Diode rectifier LA108 Battery LA408 (12V24AH) Key switch 066-00003-30 Electric starter START Fig. 8-3 8-4 MODEL WITH OIL SENSOR Yellow To LED Lamp Yellow / Red Oil sensor Orange...

  • Page 56: Electric Starter

    9. ELECTRIC STARTER EX 17, 21 9-1 SPECIFICATIONS 129.5 Pinion gear Models EX17, 21 Model EX27 Voltage Power (kW) Weight (kg) EX 27 PINION GEAR 157.8 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.
  • Page 57 9-3 COMPONENT PARTS (Models EX17 and EX21) PINION AY FRONT COVER MAGNETIC SWITCH PINION STOPPER SET BATTERY CABLE THROUGH BOLT (2 pcs.) O - RING WASHER YOKE AY O - RING ARMATURE AY BRUSH SPRING (BRUSH) REAR COVER BRUSH HOLDER (Model EX27) MAGNETIC SWITCH PINION AY...

  • Page 58: Oil Sensor

    10. OIL SENSOR 10-1 SPECIFICATIONS Float type Type (with lead switch incorporated) Resistance 100 M ohms or over (at FULL oil level) Operating OIL SENSOR -30 to +180 degree Celsius Temperature Fig.10-1 10-2 CONSTRUCTION AND OPERATION The oil sensor is composed of the float, permanent magnet incorporated into the float and the oil sensor.

  • Page 59: Automatic Decompression System

    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.

  • Page 60: Carburetor

    12. CARBURETOR 12-1 SPECIFICATIONS EX13 EX17 EX21 EX27 A/C Type DUAL DUAL DUAL 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 ← 40.0 ← Pilot Screw Turning 1-3/4 ← 1-1/4 ←...
  • Page 61 FUEL SYSTEM OUTLINE FUEL NEEDLE VALVE FLOAT FLOAT CHAMBER Fig. 12-1 PILOT OUTLET PILOT JET BYPASS PILOT AIR JET MAIN NOZZLE AIR INTAKE PORT CHOKE VALVE FLOAT MAIN AIR JET MAIN JET Fig. 12-2 - 58 -...
  • Page 62 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 EX13, 17, 21 MODEL EX27 13 14 Fig. 12-3...
  • Page 63 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 is removed, the spring can be taken out. (2) Remove the phillips screw and the throttle valve , then take out the throttle shaft When removing the throttle valve, take care not to damage the valve edge.

  • Page 64: Recoil Starter

    13. RECOIL STARTER 13-1 RECOIL STARTER Tools required: Screwdriver, pliers and protective 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.
  • Page 65 (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 GUIDE order. FRICTION (3) Remove the reel. (Fig. 13-2) SPRING -1 Hold down the reel gently to keep it from RATCHET...
  • Page 66 (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 Set screw not to move the ratchet. (Fig.13-6) Ratchet guide Friction spring Ratchet guide sub-assembly...
  • Page 67 (5) Install the rope NOTE: This procedure requires 2 people. -1 Pass the rope end through the rope guide and the Approx. 20mm 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 .
  • Page 68 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 missing parts such as the friction spring. (2) Pull out the starter knob as far as it will go.

  • Page 69: Installation

    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.
  • Page 70 14-5 POWER TRANSMISSION TO DRIVE MACHINES 14-5-1 BELT DRIVE Note the 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. •...

  • Page 71: Troubleshooting

    15. 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 presented here is not all.
  • Page 72 Problem 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 valve and seat contact Repair or replace 6) Valve stem seizure Repair or replace...
  • Page 73 Problem and possible cause Remedy 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 Replace 5) Crankshaft oil seal (front, rear) defect 2.
  • Page 74 ELECTRIC STARTER Engine does not start Check battery charged Charge or replace the battery. state and battery terminal Does the Does the Repair connection or connection or corrosion crank run? starter run? corrosion of battery terminals. for any abnormality. Key switch Connected state Operation sound of Check/repair wiring to the...
  • Page 75 Problem 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 KEY SWITCH wiring rusting, or dust sticking. continuity of the terminals and key Carefully check inserting switch and repair or replace if...
  • Page 76 Problem and check item Description Remedy Motor idles and engine does not (1) Remove and check the starter. Check Check engaged run. or replace the pinion clutch if state of pinion and necessary. ring gear. (2) Check battery charged state and battery terminal connection or corrosion for any abnormality.

  • Page 77: Standard Repair Tables

    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 Limit CYLINDER HEAD * Flatness EX13 EX17 0.05 EX21 (0.002) (0.004) EX27 * Intake/exhaust valve seat...
  • Page 78 Unit: mm (in.) ITEM Limit CYLINDER 58.000 - 58.019 EX13 * Inner diameter (2.2835 - 2.2842) To be rebored when the difference between EX17 67.000 - 67.019 Standard max. and min. of EX21 (2.6378 - 2.6385) diameter reached to 0.1 (0.004).
  • Page 79 Unit: mm (in.) ITEM Limit PISTON EX13 0.035 - 0.080 0.15 EX17 * Ring groove side clearance EX21 Second (0.0014 - 0.0031) (0.0059) EX27 0.02 - 0.075 EX13 (0.0008 - 0.0031) Oil ring EX17 0.01 - 0.065 0.15 Coil exp EX21 (0.0004 - 0.0026)
  • Page 80 Unit: mm (in.) ITEM Limit CONNECTING ROD * Large end inner diameter EX13 30.000 - 30.016 30.1 EX17 (1.1811 - 1.1817) (1.1850) EX21 34.500 - 34.516 34.1 EX27 (1.3386 - 1.3392) (1.3425) * Clearance between large EX13 end and crank pin EX17 0.020 - 0.049...
  • Page 81 Unit: mm (in.) ITEM Limit CAMSHAFT * Cam peak height (intake and exhaust) EX13 Cam peak EX17 29.028 - 29.128 28.98 height EX21 (1.1428 - 1.1468) (1.1409) EX27 EX13 Cam inner EX17 9.0 - 9.036 9.05 diameter EX21 (0.3563) (0.3543 - 0.3557...
  • Page 82 Unit: mm (in.) ITEM Limit VALVE SPRING FREE LENGTH EX13 EX17 27.4 EX21 (1.0787) EX27 VALVE SEAT ANGLE (INTAKE AND EXHAUST) * Valve cutter angle (a) * Valve contact width (b) EX13 a: 90° Intake EX17 b: 0.7 - 1.0...

  • Page 83: Tightening Torque

    28.0 - 30.0 280 - 300 20.3 - 21.7 flange bolts M8 × 35 flange bolt 17.0 -19.0 170 - 190 12.3 - 13.7 EX13,17,21 13.0 - 15.0 130 - 150 9.4 - 10.8 Connecting rod cap bolts EX27 17.0 - 20.0 170 - 200 12.3 - 14.5...

  • Page 84: Maintenance And Storage

    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.
  • Page 85 17-5 INSPECTION AND MAINTENANCE EVERY 300 HOURS MAINTENACE ITEMS REASON / REMARKS (1) Inspect the intake and exhaust valve clearance. (1) Incorrect clearance can cause low power output Adjust if necessary. and engine malfunction. 17-6 INSPECTION AND MAINTENANCE EVERY 500 TO 600 HOURS (EVERY 6 MONTHS) MAINTENACE ITEMS REASON / REMARKS (1) Remove the cylinder head and remove any carbon.
  • Page 87 SERVICE INFORMATION...
  • Page 89 PREFACE This portion of the manual covers the service information, trouble shooting procedures of the EX21 E FI (Electronic Fuel injection) engine. Careful observance of the instructions given herein will result in better, safer and faster service work. For more detailed instructions of disassembling and reassembling procedures, please refer back to the standard service procedure CONTENTS Section...

  • Page 90: Specifications

    1. SPECIFICATIONS Model EX21D Air-Cooled, 4-Cycle, Slant Single-Cylinder, Type 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 3 .2(4 .4)/3000 Continuous Output...

  • Page 91: Description Of Fuel System

    2. DESCRIPTION OF FUEL SYSTEM This engine is equipped with electronic fuel This engine is equipped with electronic fuel injection. THROTTLE BODY AY injection . The fuel system consists of a throttle body assembly, power generation module, wire The fuel system consists of a throttle body harness, crankcase air pulse hose, fuel pressure assembly, power generation module, wire return pipe and a fine mesh fuel filter.

  • Page 92: Disassembly And Reassembly

    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 .

  • Page 93: Disassembly Procedures (Difference)

    3-3 DISASSEMBLY PROCEDURES (DIFFERENCE) Step Parts to remove Renarks and procedures Parts Fasteners Fuel tank (1) Drain fuel from the tank . 10 mm spanner or box wrench (2) Remove the fuel tank mounting nuts and bolts from M6 nut : 2 pcs . the crankcase .
  • Page 94 Step Parts to remove Renarks and procedures Parts Fasteners Throttle body, (1) Disconnect the fuel pump pulse line from the throttle body . Insulator (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 .
  • Page 95 Step Parts to remove Renarks and procedures Parts Fasteners EFI power generation module Remove the EFI power generation modudle . M6 × 20mm : 2 pcs . + screwdriver POWER COIL CP VIEW SCREW AND WASHER AY POWER COIL CP - 6 -...

  • Page 96: Reassembly Procedures (Difference)

    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 .

  • Page 97: Wiring Diagram

    4. WIRING DIAGRAM MODEL WITH EFI Spark plug Black Ignition coil Throttle body Power coil Orange EFI system Fuel injection Oil sensor Yellow Temperrature sensor Throttle bracket Crankcase - 8 -...

  • Page 98: Throttle Body

    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 performance (including starting, acceleration, fuel consumption, output power characteristics) .

  • Page 99: Fuel System Outline

    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 .
  • Page 100 5-4-1 CHECK CRANKCASE OIL LEVEL AND FOLLOW STARTING PROCEDURE (1) Check the oil level and add or drain oil until to the proper crankcase level. Low oil or overfilled crankcase oil can cause fuel pump malfunction due to low crankcase vacuum or a pump restriction due to oil carry over into the pump.

  • Page 101: Installation

    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.

  • Page 102: Troubleshooting

    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 .
  • Page 103 Problem 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 valve and seat contact Repair or replace 6) Valve stem seizure...
  • Page 104 Problem and possible cause Remedy 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 .

  • Page 105: Engine Will Not Start

    ENGINE WILL NOT START Engine does not start Spark plug improperly Clean, regap or replace None or Weak gapped, dirty or fouled Check engine as necessary or defective spark None or Weak Wiring damaged Repair of replace Good None or Weak Ignition coil - wrong gap Repair of replace to flywheel or defective...

  • Page 106: Maintenance And Storage

    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 every day, rather than every 100 hours .
  • Page 107 8-5 INSPECTION AND MAINTENANCE EVERY 300 HOURS MAINTENACE ITEMS REASON / REMARKS (1) Inspect the intake and exhaust valve clearance . (1) Incorrect clearance can cause low power output Adjust if necessary . and engine malfunction . 8-6 INSPECTION AND MAINTENANCE EVERY 500 TO 600 HOURS (EVERY 6 MONTHS) MAINTENACE ITEMS REASON / REMARKS (1) Remove the cylinder head and remove any carbon .

  • Page 108: Organize

    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 either .
  • Page 109 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 .
  • Page 110 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 and checking the air filter .
  • Page 111 - 23 -...
  • Page 113 PRINTED IN THE USA...

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