GENERAL INFORMATION. REDUCTION GEAR A l/2 reduction gear is anava,ilable option on the engines.

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2 GENERAL INFORMATION Wisconsin Robin WO1-115, 150 and 210 engines are of the four cycle type, in which each ofathe four operations of suction, compression, expansion and exhaust constitutes a complete stroke. This produces one power stroke for each two revolutions of the crankshaft. These engines provide dependable service with quality and strength where they are needed. A heavy cast iron cylinder liner, forged steel crankshaft and camshaft, forged alloy bearings and an aluminum alloy connecting rod, all add up to improved durability. MECHANICAL DECOMPRESSOR For easy engine starting, a mechanical decompressor is mounted on the camshaft to decrease the recoil pulley force. The decompressor opens the exhaust valve before compression reaches the maximum to reduce the compression pressure, which in turn decreases the recoil pulley force. IGNITION SYSTEM A pointless magneto ignition system is standard on these engines. This system, referred to ast.i.c. (Transistor Ignition Circuit), is completely free of problems associated with breaker point type ignition systems such as start-up failure due to dirty, burnt or oxidized point surfaces, low ignition efficiency because of moisture, rough breaker point surface and incorrect timing resulting from worn mechanical parts. A Solid State Ignition System is anavailable option. LUBRICATION An oil scraper on the connecting rod cap splashes oil in the crankcase on the rotating and sliding parts. COOLING Cooling is accomplished by a flow of air circulated past the cylinder walls and head fins from a combination fan-flywheel encased in a sheet metal shroud. Air is divided and directed by ducts and baffle plates to insure uniform cooling of all parts. CARBURETOR The engines are equipped with a horizontal draft carburetor that has a float controlled fuel system. The carburetor has been carefully set to assure satisfactory start-up, acceleration, fuel consumption and output performance. A fuel pump is standard on WO1-115 and WOl-150 carburetors only.the fuel pump improves engine operation at a tilted angle. GOVERNOR A centrifugal flyweight governor controls the engine speed by varying the throttle opening to suit the load imposed upon the engine. REDUCTION GEAR A l/2 reduction gear is anava,ilable option on the engines. ROTATION Rotation of the crankshaft is clockwise when viewing from the flywheel side of the engine. This gives counterclockwise rotation at the power take-off end of the crankshaft. AIR CLEANER The engines are equipped with an oval air cleaner with a sponge element. A cyclone type air cleaner with semi-wet double elements are an available option for the engines. OIL GRADE CHART Crankcase Capacity E:;: 1.27 pts. (0.60L) WOl-2 10 I 1.37 OtS. (0.65U f "Use oilsclassified as Service I SE or SF I Seasons or Temperature I Gradeof Oil I 1 Spring, Summer or Autumn (+49'C to +4"a I +120"F to +40 F SAE30 Winter I +40"F to +15"F 1 SAE2O I (+ST to -9X) Below +15"F (-9 C) SAEl OW

3 IGNlTlC Figure 1-1. Sectional Views of Engine Models WO1-115 and WO

4 VALVE ROCKER ARM I Figure 1-2. Sectional View of Engine Models WO1-115 and WO

5 Figure 1-3. Sectional View of Engine Model 21 0 I 14

6 r CAR3URETOR Figure 1-4. Sectional View of Engine Model

7 SPECIFICATIONS Model WO1-115 WO1-150 wo1-210 Type Air-Cooled 4-Cycle, Vertical Shaft, Single Cylinder, Overhead Valve, Gasoline Engine Bore 2.28 in. (58 rnm) 2.52 in. (64 mrn) 2.83 in. (72 mrn) Stroke 1.69 in. (43 rnrn) 1.81 in. (46 mm) 2.05 in. (52 mm) Displacement 6.93 cu. in. (1 13 cc) 9.02 cu. in. (1 47 cc) cu. in. (21 1 cc) Rotation Counterclockwise Facing PTO Shaft Cooling System Forced Air Cooling Lubrication Splashing Type Lubricant SAE 30,20 or 1 OW-30 See Oil Chart. Carburetor Horizontal Draft, Float Type Fuel Regular Gasoline (Leaded or Unleaded) Fuel Consumption Ratio (gr-hp-h) 230 at continuous rated output operation Fuel Feed Gravity Type Fuel Tankcapacity 0.55 gal. (2.1 L) gal. (2.9 L) gal. (4.2 L) Reduction Ratio - '/2 - '/2 - '/2 Governor Ignition System Spark Plug Centrifugal Flyweight Type Pointless Magneto Type (Solid State Ignition) NGK BPGES or CHAMPION N9Y Light Capacity (V-W) I 12V - 15W (available, if required) Starting System Recoil Starter Net Dry Weight 26.9 Ibs(12.2 kg) 28.0 lbs.(12.7 kg) 31.6 Ibs.(14.3 kg) 32.7 Ibs(l4.8 kg) 46.4 lbs(21.0 kg) 47.5 Ibs. (21.5 kg) Length in. (308 rnrn) in. (323 mm) in. (373 rnm) Dimensions Width in. (31 4 mrn) in. (349 mm) in. (383 rnm) Height in. (31 9 mm) in. (329 rnrn) in. (41 8 mm) 1-6

8 ENGINE MAINTENANCE SCHEDULE MAINTENANCE AND STORAGE ACAUTION: Failure to follow this schedule will seriously damage the engine. Daily Every MAINTENANCE I or 8 hrs. I 20 hrs. 1 ' Add fuel to tank. Check oil level. Add to full mark. Do not overfill. Clean air intake screen. Clean cooling fins if needed. 0 Weekly I Monthly or I Semi-annual See Note or 50 hrs hrs hrs. Below *. * * Inspect unit for loose hardware, lines, or hoses. Change crankcase oil. Inspect cooling system. Remove blower housing and scrape between fins, around cylinder head and from housing. I air Clean 0 eaner. I I Check and clean Clean fuel filter and fuel tank. Clean contact and breaker points. Disassemble and clean carburetor. Remove carbon from cylinder head. a a 0 -* * I * /. I I * 1., *Under severe environmental conditions these items may need to be maintained more frequently. Cleaning Air Cleaner Remove air cleaner cover. Remove element from base. Washelement in detergentandhotwater, then dry thorou-ghly. Wipe all other components clean. Saturate element with light oil. Squeeze firmly to evenlydistribute oil andremoveanyexcess. Service daily if engine is operated in very dusty and dry grass conditions. A clogged air cleaner will result in high fuel consumption, loss of power and excessive carbon build-up in the combustionchamber. ENGINE STORAGE Ifnot properly protected, temperature and humidity changes can cause corrosion of piston rings, cylinder walls and bearing surfaces in a stored engine. For maximum protection,prepare the engineforstorageas follows: 1. Run the engine until it reaches operating temperature. Stop the engine an drain the oil from crankcasewhileengineisstillwarm. 2-1

9 2. Drain fuel lines, carburetor, fuel tank and fuel pump (if equipped), to prevent lead and gum sediment from. interfering with future operation. Gasoline fumes from gradual evaporation are a dangerous fire hazard. 3. To protect the internal components and keep them from rusting and sticking, a half and half mixture of kerosene and good engine oil (same grade as used in the engine crankcase) should be injected into the carburetor air intake. Do this while the engine is warm and running at moderate speed. Use enough of the mixture (about l/4 pint) so that a heavy, bluish smoke appears at the exhaust. This fogging operation will leave a coating of oil on the parts, protecting them from the atmosphere. 4. Turn the starting pulley by hand andleave it where the resistance is the heaviest. 5. Tape or seal off air cleaner and exhaust openings for the duration of the storage period. 6. Remove all dirt and chaff from the cooling fins. 7. Clean the engine outside with an oiled cloth. 8. It is highly recommended that machines be stored inside a building through the winter. If this is not possible, the engine should be protected from snow and ice by a suitable covering. NOTE: Before adding newcrankcase oil the next season, drain engine of condensation which may have accumulated in the crankcase during the storage period. Fill crankcase with good quality oil before starting engine (see SPECIFICATIONS). 2-2

10 The three prime requirements necessary for starting and maintaining satisfactory operation of gasoline engines are: 1. A proper fuel mixture in the cylinder 2. Good compression in the cylinder. 3. Good spark at the correct time, to ignite the mixture. There are other factors which contribute to hard starting; such as too heavy a load for the engine to turn over at low starting speed, long exhaust pipe with high back pressure, etc. These conditions may affect starting, but do not necessarily mean the engine is improperly adjusted. The most common symptoms of engine problems are given here, followed by the probable causes. ENGINE WILL NOT START, OR HARD TO START Electrical System Problems Caused By: Weak or dead battery. Poor ground connection. Defective starter. Fuel System Problems Caused By: Fuel tank empty. Improper or contaminated fuel. Damaged or loose ignition module. Faulty ignition coil. Spark plug cable wet or broken. Spark plug wet or dirty. Spark ptug point gap incorrect. Compression System Problems Caused By: Lack of lubrication on moving parts due to long storage. Carburetor not choked enough gine). Low cranking speed. Restricted cooling air circulation. (cold en- Incorrect oil grade or low oil level. Loose or broken spark plug. Damaged head gasket or loose cylinder head. Loose fittings or defective fuel lines. Carburetor needle valve held open by dirt or gum. Defective speed control or governor. Fuel or oil leaks. Ignition System Problems Caused By: Loose or corroded electrical connections. Incorrect tappet clearance. Valve stuck open due to carbon or gum on valve stem. Defective or incorrectly adjusted valve components. Worn valve guides, piston or rings. Scored or worn cylinder walls. Ignition wires disconnected or broken. 3-1

11 ENGINE MISFIRES Incorrect spark plug gap. Ignition cable leaking. Weak spark Ignition wires loose. Water or dirt in gasoline. Insufficient compression. ENGINE STOPS Fuel tank empty. Water, dirt, gum, etc. in gasoline. Vapor lock (gasoline evaporating in fuel lines due to excessive heat around engine). Vapor lock in fuel lines or carburetor due to incorrect fuel. Engine scored or stuck due to lack of oil. Air vent hole in the fuel tank cap plugged. Magneto or ignition coil faulty. ENGINE OVERHEATS Crankcase oil level low. Spark timing incorrect. Low grade gasoline used. Engine overloaded. Cooling air restricted from dirt or debris. Engine operated in confined space where cooling air is continually recirculated. Restricted exhaust. Heavy load at low engine speed. 0 ENGINE KNOCKS Low quality gasoline. Engine operating under heavy load at low speed. Carbon or lead deposits in cylinder head or on piston. Spark timing incorrect. Worn or damaged connecting rod bearing. Worn or damaged piston pin. ENGINE BACKFIRES THROUGH CARBURETOR Water or gasoline. Intake valve stuck Valves overheated, chamber. Engine cold. dirt in gasoline, or poor grade or particles in combustion ENGINE SURGES OR GALLOPS Carburetor flooded. Governor rod installed wrong, or governor of adjustment. High speed jet in carburetor partially restricted. out 3-2

12 IGNITION SYSTEM The standard ignition system for engines WO1-115, 150 and 210 is a magneto ignition system called T.I.C. (Transistor Ignition Circuit). T.I.C. consists of an ignition coil with a built-in transistor mounted on the flywheel. For initial excitation, a Solid State Ignition is an available option for these engines. SYSTEM OPERATION Figures 4-1 and 4-2 Revolution of the flywheel generates electricity on the primary side of the ignition coil, and the electric current (A) runs. (A) makes the power transistor "ON" and the electric current (B) passes. The flywheel goes round further, and at the time of ignition the electric current (C) runs, then the electric current (D) runs to the signal transistor, by which the electric current (B), passing through the power transistor, is abruptly cut; and as a result, the high voltage electricity is generated on the secondary side of the ignition coil and it sparks at the plug. Figure 4-2 illustrates the engine wiring diagram. - RESISTOR f IGNITION COIL Figure 4-1. STOP BUlTON CONNECTOR IGNITION COIL -r SPARK PLUG mrr EXCITER COIL ( (OPTION) l""1 I I I i FLYWHEEL Figure

13 SYSTEM CHECKS In the event of a malfunction of the ignition system: Check the magneto for defects. Check the high voltage wire shorted. for damage or if Faulty spark plug, caused by moisture, dirt, broken insulation or incorrect plug gap. CHECK SPARK If difficulty is experienced in starting the engine or if engine misses firing, check the strength of the ignition spark Remove the spark plug. With the ignition cable connected to it, lay the spark plug on a convenient metal part of the engine so that the gap can be observed as you rotate the crankshaft several times using the recoil starter. If a good strong spark occurs, the ignition system can be eliminated as the source of trouble. CHECK FLYWHEEL Check that the external magnet, mounted on the flywheel is in good condition. CHECK FLYWHEEL AIR GAP Figure 4-3 Use a non-metallic feeler gauge to measure the air gap between the flywheel and the ignition coil. Loosen the ignition coil hold down screws to adjust the gap to specifications (see SPECIFICATIONS ). FEELER GAUG I Figure 4-3. COIL 4-2

14 FUEL SYSTEM AND GOVERNOR FUEL SYSTEM Always use a high quality brand of leaded or unleaded gasoline free from dirt and water. Some poorer grades of gasoline contain gum which deposits on valve stems, piston rings,and in the various small passages in the carburetor. This can cause serious engine operating problems. Use gasoline with an octane rating of at least 86. Fuel with a low octane rating will cause detonation. If operation is continued under this condition, severe damage will result to the engine. Teledyne Total Power recommends fuels with no more than 10 percent alcohol content. GOVERNOR OPERATION The governor is mounted on the governor gear in the crankcase cover. As the engine speed increases, the centrifugal force in the flyweights acts against the governor spring and closes the carburetor throttle to a point where the engine speed will be maintained practically constant under varying load conditions. GOVERNOR ADJUSTMENT Figures IMPORTANT: This procedure should be necessary only if the governor lever was loosened or removed. For correct carburetor throttle opening and governor regulation, the governor lever must be properly adjusted. 1. Install governor rod and governor spring on throttle lever and governor lever. Mount governor lever on governor shaft. for models WO1-115 and WO1-150, refer to Figure 5-1. If removed, install speed control lever on cylinder head. > \ SPRY GOVERN~R ROD SPRING :I- / / \ - SPEED CONTROL LEVER GOV~RNOR SPRING GOVERNOR ROD HOOKING POSITION HIGH SPEED 2. Hook governor spring from speed control lever to governor lever. For models WO1-115 and WO1-150, refer to Figure 5-2. Fo r model WO1-2 10, refer to Figure 5-3. The governor spring may be hooked to a different position according to generator specifications. 3. Turn control lever clockwise (toward High Speed ) until throttle valve in carburetor is fully open. Hold lever in this position. IMPORTANT: Check that governor lever clamp screw is loose so governor shaft can be turned independently of lever. 60Hz Hz 4-5 Figure 5-3. GOVERNOR LEVER Figure

15 4. Refer to Figure 5-4. Insert a screwdriver in slot at end of governor shaft. Turn clockwise as far as shaft can be turned. Tighten governor lever clamp screw. 1 GOVERNOR SPRING AND GENERATOR SPECIFICATIONS Figure 5-5 For engines WO1-115 and WO1-150, there are two types of governor springs, one for 50 Hz and the other 60 Hz. The locations for either spring are listed in Figure 5-5. The differance between the springs: Dimension A is longer. 60Hz (STD) 50Hz :igure 5-4. GOVERNOR LEVER TIGHTENING BOLT GOVERNOR SHAFT I WO A WO A L Figure 5-5. WO A WO A 5-2

16 CARBURETOR FUEL PUMP Figure 6-1 The fuel pump conveys the pulsating pressure in the crankcase to the diaphragm chamber to vibrate the diaphragm and change the volume, thereby drawing and discharging the fuel. The diaphragm suction and discharge passages have one valve each which allows fuel flow in one direction only, thus preventing reverse fuel flow. FLOAT SYSTEM Figures 6-1 and 6-2 The fuel bowl (float chamber) is mounted directly beneath the carburetor body. Fuel from the fuel tank is supplied to the fuel bowl through the fuel inlet and needle valve. The fuel in the bowl is maintained at a predetermined level by the float through its control of the needle valve.the needle valve opening is regulated by the speed and load (fuel demand) of the engine. Figure 6-1. Sectional Views of Carburetor Models WO1-115 and WO1-150 i 6-1

17 IDLE SYSTEM Figures 6-1 and 6-2 The idle system supplies fuel to the engine during idle and low speed operation. Fuel is fed through the main jet to the idle jet. The fuel, measured by the idle jet, is then mixed with air from the idle air jet. This supply of fuel and air is discharged to the engine through the idle outlet. At high speeds, the throttle valve opens to allow the fuel-air mixture to be discharged from both the idle outlet and by-pass holes. MAIN (High Speed) SYSTEM Figures 6-1 and 6-2 The main system controls the air-fuel mixture during medium and high speed operation. Fuel flows from the fuel bowl, through the main jet and into the main nozzle. Here the fuel is mixed with air coming from the main air jet and admitted through the bleed holes of the main nozzle. The mixture is discharged through the top of the main nozzle as atomized fuel where it mixes with intake air to become the optimum air-fuel mixture supplied to the engine. BY-PASS HOLES Figure 6-2. Sectional Views of Carburetor Model WO

18 CHOKE SYSTEM Figures 6-1 and 6-2 The choke system provides a rich fuel-air mixture for cold weather starting. When the choke valve is closed, a low pressure area (vacuum) exists at the main nozzle. A rush of fuel with relatively small amounts of air is obtained from the main nozzle as the engine is cranked for starting. Even with a cold engine, this extra rich mixture makes starting easy. DISASSEMBLY AND REASSEMBLY Figures Besides mechanical failures, most troubles are attributed to an incorrect mixing ratio. The most common causes of incorrect fuel-air mixtures are clogged jets, restricted air and fuel passages, and variations in the fuel level. In order to obtain the full performance of the carburetor, the air cleaner and carburetor must be clean so that air and fuel flow without restriction. Using good quality, fresh, leaded or unleaded gasoline will help keep the carburetor clean. SHAFT CARBURETOR BODY CHOKE \ SPRING 13 U r\ I "IDLE JET THROI~LE SHAFT :igure 6-4. Model WO1-210 CARBURETOR BODY 4 > NOZZLE NEEDLEVALVE MAIN JET e FLOAT ~~ PIN & FLOAT FLOAT BOWL Cleaning Thoroughly clean all metal parts in a good quality carburetor cleaner and rinse in cleaning solvent. Blow out all passages in throttle body and fuel bowl with reduced air pressure. Check that all carbon deposits have been removed from throttle bore and idle discharge holes. Reverse the flow of compressed air through all passages to insure the removal of all dirt. NEVER USE A DRILL OR WIRE TO CLEAN OUT JETS OR IDLE HOLES. Throttle System Figures 6-3 and Remove screws to remove throttle valve and throttle shaft from carburetor body. Use care to avoid damaging parts. 2. Remove throttle stop screw and spring. igure 6-3. Models WO1-115 and WO

19 Choke System Figures 6-3 and Remove screws to remove choke valve and choke shaft. Use care to avoid damaging parts. 2. During reassembly, install with cut-out on valve facing main air jet. Idle System Figures 6-3 and Remove idle jet. Use care to avoid damaging parts. NOTE: Idle jet is included in repair kit. 2. During reassembly, tighten idle jet securely to prevent fuel leakage. Main Fuel System Figures 6-3 and Drain remaining fuel in fuel bowl into a suitable container. Remove bowl and gasket. 2. Remove main jet from carburetor body. NOTE: Main jet is included in repair kit. 3. During reassembly, tighten main jet securely to prevent fuel mixture from becoming too rich. Install fuel bowl and new gasket. Torque screw to specifications (see 'SPECIFICATIONS'). Float System Figures 6-3 and Remove float pin, float and needle valve. NOTE: Float pin is flattened at one end. Use a small drift punch and tap on float pin round end to remove. 2. Inspect float. Replace if dented, contains fuel, or if float axle bearing and tab contacting needle valve are worn excessively. NOTE: Special service needle valve is included in repair kit. Inspect needle valve. Replace if damaged or worn. 3. During reassembly, adjust float setting. With float chamber bowl removed, place carburetor body on end. Float surface must be parallel to carburetor body. To adjust float surface bend tab. The tab (float lever) should just contact the fuel needle valve. Install float bowl using a new gasket. Torque to specifications (see 'SPECIFICATIONS). Fuel Pump Figure Remove screws to remove fuel pump from carburetor. Use care not to lose 0-Ring. 2. Remove screws to separate fuel pump. Use care to avoid damaging parts. 3. During reassembly, keep the fuel pump free of foreign matter. FUEL PUMP BODY O-RING DIAPHRAGM MEMBRANE GASKET PRIMER CAP Figure

20 STARTING SYSTEM RECOIL STARTER Disassembly and Reassembly Figures WARNING: A loaded power spring operates A under great pressure. To avoid personal injury, use care to keep power spring in housing. DO NOT remove spring unless for replacement. 1. Refer to Figure 7-1. Pull starter knob out from housing about 16 in. (40 cm). Hold housing and reel to prevent reel from rewinding. 6 QT= FRICTION,PLATE RETURN SPRING RATCH ET NoTCH Figure Pull out rope to the inside of recoil starter and press rope into notch on reel. Release reel to let spring mechanism slowly unwind. 3. Refer to Figures 7-2 and 7-3. Remove return ' spring, friction spring or plate andratchets. 4. Refer to Figure 7-4. Slowly lift reel, turning lightly left to right, from support shaft in housing. Inspect rope. Replace if damaged or worn. CAUTION: Use rope of same length and A diameter as originally furnished. Refer to Figure 7-5. Install new rope in handle. Tie knot as illustrated about 1 % in. (35 mm) from end. Pull knot tight and fit into top of handle. Refer to Figure 7-6. Insert other end of rope through housing guide bushing and through hole in reel groove. Pull rope through cavity opening. Make knot as illustrated about 1 in. (25 mm) from end. Fit knot into cavity. Figure 7-2. Models WO1-115 and WO1-150 RATCHETS FRICTION SPRING COVER Figure 7-3. Model WO1-210 U-SNAP RING THRUST WASHER ' /FRICTION SPRING % 7-1

21 5. Inspect power spring. Replace if damaged. To remove spring, place housing on bench with spring side down and pound on bench with hammer. NOTE: For ease in assembly, replacement power springs are held together with a wire ring spring holder. START& CASE \ SPRING L i- Figure 7-5. I Figure 7-7. I To assemble new spring refer to Figure 7-7. Form a 4.5 inch (115 mm) diameter ring from a piece of 16 or 20 gauge soft iron wire and twist ends together to make spring holder. Wind spring inside wire ring by starting with outer loop of spring and winding counterclockwise. I THRU HOUSING HOLE IN GUIDE BUSHING REEL GROOVE I OUTER EDGE OF SPRING REEL HOOK GOOD 1 NOT GOOD STARTER SHAFT INNER EDGE OF SPRING Figure 7-8. Refer to Figure 7-8 to install spring. Align spring outer loop hook in the starter case housing. Press spring out of holder into recess in housing. Loop of power sprirlg must be 25/64 inch (1 cm) from support shaft. Lightly grease power spring and support shaft 7-2

22 6. Refer to Figure 7-9. Wind rope 2Y2 turns clock- : wise in reel and press rope in notch. Install reel over support shaft. Align the reel hook to the inner end of the spring and install the reel in the starter case. : Refer to Figure For Model WO1-210 bend the return spring up and install the friction spring cover asshown. Next, turn the friction spring cover clockwise till the notch. aligns with the ratchet. Install thrust washer and snap ring. 9. Test starter for satisfactory operation before mounting on engine Figure With rope pressed into notch, hold reel securely in housing and turn reel counterclockwise 4 revolutions. Remove rope from notch. Let reel slowly turn clockwise as rope winds onto reel and handle returns to guide bushing. 8. Refer to Figures 7-2 and 7-3. Install all parts as shown. Figure

23 MECHANICAL DECOMPRESSOR During Engine Operation Function Figure 7-12 The mechanical decompressor is mounted over the During engine operation, the centrifugal force that is exhaust cam on the camshaft to decrease the com- applied to the weight increases to turn the release pression pressure by opening the exhaust valve in lever so that the crescent cam goes down below the the latter half of the compression stroke 'of the working force of the exhaust cam, turning the engine. Which in turn makes it easier to start the decompressor off. engine. Starting the Engine Figure 7-11 With the weight itself, larger than the centrifugal force obtained by starting the engine, the crescent cam projects from the peak of the exhaust cam to push the tappet up. Which in turn opens the exhaust valve to decrease the pressure in starting the engine. 1 - TAPPET CRESCENT Figure

24 ENGINE REPAIR AND OVERHAUL 1 Part No. Description I w. EY Flywheel Puller w/bolts 1 1 PREPARATION AND SUGGESTIONS Provide a well lighted working area with enough space for parts and tools to be spread out. A work stand is essential for holding the engine securely. When disassembling the engine, lay parts out in the order they were removed. Have several boxes available so that parts belonging to certain groups can be kept together. Tag parts if there is a possibility of confusion. Use the PARTS MANUAL for reference during reassembly. The exploded view illustrations will help identify parts, show the components of individuaf assembly groups and show the order of reassembly. Often it is not necessary to disassemble the entire engine. The instructions contained in this manual are arranged by components. If entire engine disassembly is required, locate the reassembly instructions under headings of the various parts. NOTE: Drain oil from crankcase before disasse m bly. While the engine is partly or fully dismantled, clean and inspect all parts and replace as needed. During reassembly use new gaskets and lubricate all bearing surfaces. Torque parts to specifications where given (see SPECIFICATIONS ). Use caution in tightening all other screws and nuts to avoid stripping threads or breaking flanges. DISASSEMBLY AND REASSEMBLY MODELS WO1-115 AND WO1-150 Air Cleaner 1. Remove air cleaner cover and element. 2. Remove air cleaner base from carburetor. Remove breather pipe Remove front cover from blower housing. 4. During reassembly refer to air cleaner maintenance instructions. (See MAINTENANCE SC H ED U LE. ) Control Panel 1. Disconnect switch lead from connector. 2. Remove panel from cylinder head and carburetor. 3. Remove choke knob from shaft. Muffler Remove muffler cover, muffler and heat deflector from crankcase. During reassembly note the direction of the muffler gasket. Recoil Starter and Blower Housing 1. Remove recoil starter assembly. 2. Inspect condition of rope. (See Starting System section if replacement is needed). 3. Remove blower housing from crankcase and cylinder head. Governor Lever and Carburetor Figure Loosen governor lever clamp screw to remove lever from governor shaft. I 2. Remove governor spring. 3. Disconnect fuel lines. 4. Remove rod spring. 5. Remove carburetor from cylinder head. Twist slightly to disconnect governor rod from governor lever and throttle lever. \ GOVERN~R ROD SPRING Figure 8-1. GOVERNOR LEVER

25 6. During reassembly refer to 'Governor Adjustment'. Fuel 'Tank 1. Disconnect fuel pipe and remove fuel tank. 2. During reassembly install a new fuel line. NOTE: Continue disassembly and see Flywheel. reassembly, DISASSEMBLY AND REASSEMBLY MODEL WO1-210 Fuel Tank 1. Disconnect fuel pipe between strainer and carburetor. Remove tank and bracket. 2. During reassembly install a new fuel line. Recoil Starter and Blower Housing 1. Remove recoil starter assembly 2. Inspect condition of rope. (See Starting System section if replacement is needed.) 3. Remove blower housing from crankcase and cylinder head. Muffler Remove muffler cover, muffler and bracket from crankcase. Head Cover Remove head cover from cylinder head. Air Cleaner and Control Panel 1. Remove air cleaner cover, elements and retainers. 2. During reassembly refer to air cleaner maintenance instructions. (See 'MAINTENANCE SCHEDULE.') 3. Remove cleaner case and control panel. Governor Lever and Carburetor 1. Loosen governor lever clamp screw to remove lever from governor shaft. 2. Remove governor rod and rod spring from carburetor. 3. Remove carburetor from intake manifold. 4. During reassembly refer to 'Governor Adjustment'. Manifold and Insulator 1. Remove insulator from manifold and cylinder head. 2. Remove intake manifold from cylinder head. DISASSEMBLY AND REASSEMBLY ALL MODELS Flywheel Figures 8-2 and Remove blower housing. Install socket wrench on flywheel nut and strike sharply with a soft hammer. Remove nut, spring washerand starting pulley. Figure 8-2. 'ig u re Install flywheel puller EY (see Figure 8-4). Turn center bolt clockwise -until flywheel becomes loose enough to be removed. COIL I 1 Figure

26 If puller is not available: Screw flywheel nut flush with, end of crankshaft to protect shaft threads from being damaged. Place the end of a large screwdriver between the crankcase and flywheel in line with the keyway. Strike the end of the flywheel nut with a babbitt hammer and at the same time wedge outward with the screwdriver. A CAUTION: During reassembly DO NOT drive flywheel onto taper of crankshaft and DO NOT overtighten flywheel nut. 3. In reassembly, install key in crankshaft. Torque flywheel nut to specifications (see SPECI- FICATIONS). Ignition Coil Figure 8-4 Remove spark plug cap from high tension cable of ignition coil and remove ignition coil from crankcase. During reassembly adjust flywheel-to-ignition coil air gap to specification (see SPECIFICATIONS). Cylinder Head and Spark Plug 1. Remove blower guide, if equipped. 2. Remove spark plug from cylinder head. 3. Remove bolts to remove cylinder head and gasket. 4. Clean carbon from combustion chamber and dirt from between the cooling fins. Check the cylinder head mounting face for distortion. If distortion is greater than specification (see SPECI- FICATIONS), replace head. 5. In reassembly use new cylinder head gasket. Torque bolts to specification (see SPECI- FICATIONS). NOTE: Do not install spark plug at this time. This will ease in turning engine over for remainder of assembly. When installing spark plug, torque to specification (see SPECIFICATIONS). Intake and Exhaust Valves Figures Position engine with piston facing up. 2. Remove the cylinder head and gasket from cylinder case. 3. Refer to Figures 8-5 and 8-6. Remove rocker shaft and rocker arm. Push down on spring and pull retainer to position valve stem in retainer key hole. Remove spring and retainer. Remove valve from cylinder head. 4. Clean carbon and gum deposits from the valves, seats, ports and guides. Inspect valves, valve seats and valve guides. ROCKER SHA - Figure 8-5. Replace valves that are badly burned, pitted or warped. UP FRONT J Figure 8-6. / 8-3

27 Valve guides should be replaced when valve stem clearance exceeds specifications (see 'SPECI- FICATIONS'). Draw valve guides out and press new guides in. Refer to Figure 8-7 for clearance specifications and proper assembly. 5. After replacing valves and valve guides, lap valves in place until a uniform ring shows around the face of the valve. Clean valves, and wash block thoroughly with a hot solution of soap and water. Wipe cylinder walls with clean lint-free rags and light engine oil. SPRING RETAINER VALVE SPRING VALVE and VALVE GUIDE CLEARANCE A-VALVE FACE ANGLE B-SEAT ANGLE C-GUIDE INSIDE DIA. VALVE STEM O.D. CLEARANCE BETWEEN VALVE STEM AND VALVE GUIDE Figure 8-7. INTAKE EXHAUST ' INTAKE EXHAUST ' WO1-115 and WO1-150 wo1-210 WO1-115, WO1-150 wo1-210 WO1-115, WOl-150 wo1-210 WO1-115, WO1-150 wo1-210 WO1-115, WO1-150 wo _ so 45" in. ( mrn) in. ( mm) in. ( mm) in. ( mm) in. ( mm) in. ( mrn) in. ( mrn) in. ( rnrn) in. ( rnm) in. ( rnrn) Check Tappet Clearance Figure 8-8 NOTE: Tappet clearance must be measured with engine cold. 1. Measure clearance with tappet in its lowest position. If clearance is less than specification (see 'SPECIFICATIONS') grind valve stem end a little at a time and remeasure. Stems must be ground square and flat. Replace valve if clearance is too large. 2. During reassembly check operation ofvalves by turning. crankshaft. Remeasure tappet clearance. Figure

28 Crankcase Cover Figures Refer to Figure 8-9. Place a rug under the engine to absorb excess oil, and remove crankcase cover bolts. Use a soft hammer and evenly tap around outer surface of cover until it breaks free from crankcase. Carefully remove cover to avoid damage to oil seal from crankshaft. Dowel pins will remain in crankcase flange. 5. Install crankcase cover using an oil seal sleeve to avoid damaging oil seal with crankshaft. Refer to Figure Align governor gear teeth to mesh with camshaft gear teeth. Tap cover into place with a soft hammer and remove oil sleeve. m CRANKCASE COVER Figure Figure Refer to Figure Inspect bearings, oil seal, and governor gear. Replace if damaged or worn. 3. Before installing crankcase cover measure crankshaft end play (see Check Crankshaft End Play ). Adjust if necessary. 4. Lubricate oil seal and bearing surfaces. Add a light film of oil on crankcase machined face to hold gasket in place. 6. Torque crankcase cover bolts to specification (see SPECIFICATIONS). Governor Gear Figure To replace governor gear, pry off gear with a screwdriver. GOVERNOR GEAR \ \- Figure Figure

29 Camshaft and Tappets Figure Place crankcase on its side to prevent tappets from falling or being damaged. Push tappets in to clear cam lobes. Remove camshaft. CAUTION: Tappets must be installed in their A original positions. This eliminates unnecessary valve stem grinding for obtaining correct tappet clearance. Mark tappets and crankcase prior to removal to prevent error. 2. Remove tappets. 3. In reassembly, install tappets in their original positions. Push in fully to avoid damage during camshaft installation. 4. Respect camshaft bearing surface for wear or damage. Lubricate bearing surface before reassembly. 5. Refer to Figure Align timing marks on camshaft and crankshaft when installing. Connecting Rod and Piston Figures 8-14 and Scrape off all carbon deposits that might interfere with removal of piston from upper end of cylinder. 2. Straighten bent tabs of lock plate to remove bolts from connecting rod cap. Remove plate and cap. 3. Turn crankshaft until piston is at top dead center. Push connecting rod and piston assembly out through top of cylinder. 4. Remove snap rings and piston pin to remove connecting rod from piston. 5. Refer to Figure Measure the diameter of the piston at center of piston skirt thrust faces. Replace piston if measurement is not within specifications (see 'SPECIFICATIONS'). TIMING MARK (CAM GEAR) Figure ~IMING MARK (CRANK GEAR) Figure Measure the cylinder bore and inspect for out-ofround and taper. If cylinder is scored or worn more than specification (see 'SPECIFICA- TIONS'), it should be rebored and fitted with an oversize piston and rings. 7. Measure connecting rod and piston for specifications and clearances. (See 'SPECI-. FICATIONS'). 8-6

30 8. Refer to Figure Before installing the piston in the cylinder, oil the piston, rings, piston pin, rod bearings and cylinder wall. Stagger the piston ring gaps 90" apart around the piston. Use a piston ring compressor when installing piston. Turn crankshaft to bottom of stroke. Align match mark on connecting rod with flywheel side of crankcase. On STD type engines, match the mark 'DF' on the piston with the mark 'MAG' on connecting rod. For reduction type engines, match the mark 'BF'. Tap piston into cylinder until rod contacts crank pin. 9. Install connecting rod cap with oil scraper on governor shaft side. Use a new rod bolt lock plate when installing connecting rod bolts. Torque to specifications (see 'SPECIFICA- TIONS'). Check for free movement of connecting rod by turning crankshaft slowly. If satisfactory, bend tabs on lock plate against flat of connecting rod bolts. Piston Rings Figures 8-16 and To prevent piston rings from becoming distorted or broken, use ring a expander tool remove rings. CAUTION: During reassembly,assemble bot- A tom ring first and work upward, installing top ringjast. Refer to Figure Spread ring only far enough to slip over piston and into correct groove. Use care not to distort ring. 2. Refer to Figure Install oil ring first. If installing replacement rings, install second ring with scraper edge down, otherwise oil pumping and excessive oil consumption will result. Install top ring last. I I Stagger the piston ring gaps 90" apart around the piston. Figure Figure PISTON RING GUIDE CONNECTING ROD / CRANKCASE Figure

31 Crankshaft Figures 8-18 and Remove key from Crankshaft. Tap lightly on crankshaft end. Remove crankshaft, using care to avoid damage to oil seal. 2. Refer to Figure 8-18 for specifications and clearances. (See 'SPECIFICATIONS' for additionalinformation.) CRANKSHAFT DIMENSIONS P-CRANKSHAFT PIN DIA. WO in. ( mm) WO in. ( mm) I wo in. ( mm) "CRANKSHAFT JOURNAL WO1-115, WO in. ( mm) O.D. MAG. wo in. ( mm) D-CRANKSHAFT JOURNAL WO1-115, WO1-150 O.D. DRIVE wo in. ( mm) Figure in. ( mm) CRANKCASE 4. Wedge a screwdriver between the flywheel and crankcase. The movement of the flywheel away from the engine block will register as end play on the dial. Check for free movement of connecting rod by turning crankshaft slowly. If satisfactory, bend tabs on lock plate against flat of connecting rod bolts. If end play is not within specifications (see 'SPECIFICATIONS) use the dial indicator reading as a guide in selecting an adjusting shim. Remove crankcase cover and install new shim. Recheck end play. CRANKSHAFT Figure Refer to Figure During reassembly, use an oil seal guide to avoid damage to crankshaft oil seal. Check Crankshaft End Play Figure 8-20 Check end play after crankcase cover and flywheel have been installed. I. Tapendof crankshaft with a soft hammer to shoulder crankshaft against main bearing at flywheel end. 2. Tap crankshaft from flywheel end to seat adjusting shim against main bearing at take-off end. 3. Attach a dial indicator to one of the tapped holes on the face of the crankcase cover. Set the dial at 0. Figure a 3 8-8

32 ENGINE REASSEMBLY Rebuild the engine reverse order, and by following the reassembly instructions which are included with the disassembly procedures. After complete reassembly, turn the engine over using the starting pulley to check for any abnormal conditions or loose fitting parts. Review and check the following: Crankshaft end play. Ignition spark. Governor adjustment. Fill crankcase with correct grade of oil. TEST REBUILT ENGINE An engine that has been completely overhauled by having the cylinder rebored and fitted with a new piston, rings, valves and connecting rod should be thoroughly RUN-IN before being put back into service. Good bearing surfaces and running clearances between the various parts can only be established by operating the engine under reduced speed and loads for a short period of time. While the engine is being tested check for oil leaks. Make final carburetor adjustment and regulate the engine operating speed. I LOAD SPEED \ RUN-IN TIME 1 NO LOAD NO LOAD NO LOAD 40% LOAD 75% LOAD 2,500 rpm 3,000 rpm 3,600 rpm 3,600 rpm 3,600 rpm 10 minutes 10 minutes 10 minutes 30 minutes 60 minutes

33 NOTES

34 SPECIFICATIONS ITEM MODEL STANDARD SIZE Camshaft Cam Lobe WO1-115 Height (Intake and Exhaust) in. (29 rnm) WO1-150 WO in.(30.8 mm) Camshaft Journal O.D. Drive Side All in. (15 rnm) Camshaft Journal O.D. Magneto Side WO1-115 WO in. (15 mm) Valve Seat Contact Width Valve Guide I.D. Valve Spring Free Length WO1-210 WO1-115 WO1-210 WO1-115 ' in. (25.mm) in. (5.5 mm) WO in. (6.6 rnm) TOLERANCE iz in. (fo.l mm) in. ( mm) CORRECTIONS in. ( mm) in in. (0.7-1.O mm) in. ( mm) LIMIT in. (-0.25 mm) in. (-0.05 mm) in. (2.0 mm) in. (0.1 5 mm) in. (- 1.5 mm) Exhaust in. (8 mrn) Shaft Rocker O.D in. (12 mrn) in. (-0.08 rnm) in. (1 2 mm) Clearance

35 ~~ SPECIFICATIONS ITEM Cylinder Head Flatness Cylinder Bore (DIA.) CORRECTIONS STANDARD SIZE MODEL TOLERANCE LIMIT I Cylinder Roundness Cvlindricitv Piston O.D. (at Skirt in Thrust Direction). Incl. Oversize E: in. (+0.25 mn C: in. (+0.5 mm in. ( mm) in. (-0.1 mm) Piston Ring Groove Width in. (0.15 mm) Piston Pin Hole (DIA.) Piston Pin O.D. Piston-to-Cylinder Clearance in. (0.025 mm) Piston Ring-to-Ring Groove Clearance in. (0.15 mm) Piston-to Piston Pin Clearance Piston Ring End Gap wo1-210 WO1-115 WO1-150 wo1-210 Oil Oil in. ( mm) in. ( mm) L:Loose T:Tight 9-2

36 ftem Piston Ring Width Connecting Rod I.D. Large End Connecting Rod I.D. Small End Connecting Rod-to- Crankpin Clearance Connecting Rod-to- Piston Pin Clearance Connecting Rod Large End Side Clearance Parallelism Between Large End and Small End Bores Disfance Between Large End and Small End Bores Crankpin O.D. Crankpin O.D. SPEC1 FICATIONS I- CORRECTIONS STANDARD SIZE MODEL TOLERANCE in. WO1-115 Top in. (1.5 mm) ( mm) in. 2nd in. (1.5 mm) ( mm) in. Oil in. (2.5 mm) ( mm) WO1-150 Top0.059 in.(1.5 mm) in. WO nd in. (1.5 mm) ( mm) WO1-150 I Oil in. (2.5mm) I WO1-210 WO1-115 WO1-150 Oil0.118in.(3.0rnm) in. (26 mm) in. (30 mm) in. (0 f0.013 mrn) in. ( mm) in. WO in. (34 mm) ( i mm) WO in.(13mm) in. LIMIT in. (-0.1 mm) in. (0.1 mm) WO in. (16 mm) (+O.OlO rnrn) in. (0.08 mm) in. WO in.(17 mm) ( mm) in. ( mrn).0079 in. (0.2 rnm) WO1-115 WO1-150 wo1-210 WO1-115 WO1-150 wo1-210 WO1-115 WO1-150 wo1-210 WO1-115 WO1-150 WO1-210 WO1-115 WO1-150 WO in. (73 rnm) in. (79 mm) in. (95 mm) in. (26 mm) in. (30 mm) in. (34 mm) in. ( mm) in. ( mm) in. ( mm) in. ( mml in. ( rnm) in. ( mml in. (0.1 2 mm) in. (1.0 mm) in. (0.06 mm) in. (0.1 mm) f in. (fo.l mm) f0.006 in. (f0.15 mm) in. ( mm) in. ( mm) Less than in. (0.005 mm) Less than in. (0.005 mm) in. (0.1 5 mm) Parallelism Crankshaft Journal O.D. Drive Side Crankshaft Journal O.D. Magneto Side Crankshaft End Play WO1-115 WO1-150 WO1-210 WO1-115 WO1-150 WO in. (25 mm) in. (30 mm) in. (25 mm) in.(30 mm) Less than in. (0.008 mrn) in. ( mm) in. ( mm) in. ( mm) in. (-0.05 mm) 9-3

37 I SPECIFICATIONS ITEM IENGINE MODEL1 TORQUE (ft-lb) 1 TORQUE (in4b) 1 TORQUE (kg-cm) I WO Cylinder Head Bolts w01 -i I wo Connecting Rod Bolts I WO1-115 I I I I WO1-I 50 I wo WO1-115 Maaneto ClamD Nuts WO I wo WO1-115 Main Bearing Cover Bolts WO wo Spark Plug

38 SU6ARU ~bin America, Inc L i v e l y B l v d. l W o o d D a l e, I L l P h o n e : ~ l F a x : e - m a i l : s a l e. r o b i n a m e r i c a. c o m l w w w. r o b i n a m e r i c a. c o m PRINTED IN THE U S A I