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LAWN-BOY V-ENGINE SERVICE MANUAL

Table of Contents – Page 1 of 2

REFERENCE SECTION

    

SAFETY

    SPECIFICATIONS - ENGINE SPECIFICATIONS

    

SPECIFICATIONS - ENGINE FASTENER TORQUE REQUIREMENTS

    

SPECIFICATIONS - CARBURETOR SPECIFICATIONS (WALBRO LMR-16)

    

SPECIAL TOOL REQUIREMENTS

    

TROUBLESHOOTING

    

MAINTENANCE

SECTION 1      WALBRO LMR-16 CARBURETOR

    

LMR-16 CARBURETOR - IDENTIFICATION

    

LMR-16 CARBURETOR - THEORY OF OPERATION

    

LMR-16 CARBURETOR - GOVERNOR THEORY

    

LMR-16 CARBURETOR - REMOVAL

    

LMR-16 CARBURETOR - DISASSEMBLY

    

LMR-16 CARBURETOR - CLEANING AND INSPECTION

    

LMR-16 CARBURETOR - ASSEMBLY

    

LMR-16 CARBURETOR - PRESETTING THE GOVERNOR

    

LMR-16 CARBURETOR - ASSEMBLING AIR BOX TO CARBURETOR

    

LMR-16 CARBURETOR - INSTALLATION

    

LMR-16 CARBURETOR - FINAL CHECK

    

LMR-16 CARBURETOR - CHOKE ADJUSTMENT

    

LMR-16 CARBURETOR - SERVICING THE AIR FILTER

    

LMR-16 CARBURETOR-TROUBLESHOOTING

SECTION 2      PRIMER START CARBURETOR

    

PRIMER START CARBURETOR - IDENTIFICATION

    

PRIMER START CARBURETOR - THEORY OF OPERATION

    

PRIMER START CARBURETOR - GOVERNOR THEORY

    

PRIMER START CARBURETOR - REMOVAL

    

PRIMER START CARBURETOR - DISASSEMBLY

    

PRIMER START CARBURETOR - CLEANING AND INSPECTION

    

PRIMER START CARBURETOR - ASSEMBLY

    

PRIMER START CARBURETOR - INSTALLATION

    

PRIMER START CARBURETOR - PRESETTING THE GOVERNOR

    

PRIMER START CARBURETOR - FINAL CHECK

    

PRIMER START CARBURETOR - SERVICING THE AIR FILTER

    PRIMER START CARBURETOR TROUBLESHOOTING

    

ENGINE STARTS HARD

    

ENGINE RUNS RICH

    

ENGINE RUNS LEAN

    

FUEL LEAKS FROM CARBURETOR

Содержание V-Engine

Страница 1: ...TOR ASSEMBLING AIR BOX TO CARBURETOR LMR 16 CARBURETOR INSTALLATION LMR 16 CARBURETOR FINAL CHECK LMR 16 CARBURETOR CHOKE ADJUSTMENT LMR 16 CARBURETOR SERVICING THE AIR FILTER LMR 16 CARBURETOR TROUBL...

Страница 2: ...ION SYSTEM CD PACK REMOVAL INSTALLATION IGNITION SYSTEM FLYWHEEL OPERATION IGNITION SYSTEM FLYWHEEL REMOVAL IGNITION SYSTEM FLYWHEEL INSTALLATION SECTION 5 REWIND STARTER REWIND STARTER OPERATION REWI...

Страница 3: ...V Engine...

Страница 4: ...nce Schedule 19 Air Filter 19 Spark Plug 20 Cleaning the Exhaust System 21 Service Section Section 1 LMR 16 Carburetor Identification 25 Theory of Operation 25 Governor Theory 25 Removal 26 Disassembl...

Страница 5: ...ly 34 Cleaning and Inspection 34 Assembly 34 Installation 35 Presetting the Governor 35 Final Check 35 Servicing the Air Filter 36 Troubleshooting 36 Section 3 Section 4 Fuel System Operation 37 Cap S...

Страница 6: ...oval Installation 41 Flywheel Operation 41 Removal 41 Installation 42 Section 5 Section 6 Rewind Starter Operation 43 Removal and Disassembly 43 Reassembly 44 Engine Description Theory of Operation Se...

Страница 7: ...TABLE OF CONTENTS Service Section cont d Section 7 PivotingZone Start Brake Introduction 53 Operation 53 Disassembly 53 Assembly 54 Appendix A Exploded View Diagrams A 1 Table of Contents 6 V Engine...

Страница 8: ...gineis running Treat all normally moving parts as if they were moving whenever the engineis running or has Avoid burns Do not touch the engine whileit is running or shortly after it has been running A...

Страница 9: ...capacity Ignition type CD Pack air gap Spark timing Dual circuit Walbro float type with fixed main jet Single circuit Lawn Boy with fixed main jet float type with primer 32 l premixunleadedregular 87...

Страница 10: ...60 70 in Ibs 6 7 7 8 N m 45 55 in Ibs 5 0 6 1 N m 90 110 in Ibs 10 12 N m 105 115 in Ibs 12 13 N m 300 350 in Ibs 34 39 N m 15 25in Ibs 1 7 2 8 N m 150 190 in Ibs 17 22 N m 140 200 in Ibs 16 22 N m 10...

Страница 11: ...SPECIFICATIONS Carburetor Specifications Walbro LMR 16 cont d Carburetor Specifications Primer Start 12 Reference Section...

Страница 12: ...ing flywheel or installing piston Sets correct gap on crankshaft support __ Compressesringsintopistongroovesduringinstallationofpiston Use to remove upper and lower crankshaft seals Use to properly po...

Страница 13: ...e Vibrates Excessively 16 Engine Crankshaft Will Not Turn 17 Engine Produces Mechanical Knocking Sound 17 Engine Pre Ignites 17 Engine Smokes Excessively 17 Engine Stalls I8 Spark Plug Fouled 18 Engin...

Страница 14: ...units only Take throttleoff choke position Throttle cable sadjusted st I Air cleaner plugged Replace spark plug Fouled spark plug Wash and re oil air cleaner element Carburetor needle stuck open Clean...

Страница 15: ...n ports Engine Overheats Possible Causes Remedies Cylinder head cooling fins clogged Remove foreign material and clean Cooling air intake plugged Ensure mixtureis 32 l Improper gasto oil mixture Clean...

Страница 16: ...rong spark plug too hot Install the correct type of spark plug Excessive alcohol in fuel Replace with fresh unleaded regular fuel Decarbon engine and muffler Replace with fresh unleaded fuel having no...

Страница 17: ...Engine Stalls Spark Plug Fouled Use of leaded fuel...

Страница 18: ...y season or every25 hours clean the air filter housing and element Do so more frequently under dusty conditions Notes Do not operate the engine without theair filter in place Doing so may damage the e...

Страница 19: ...ed allowing direct passage of air and dir to carburetor Spark Plug A spark plug thatis dirty pitted carbon covered or has worn electrodes may cause hard starting and poor operation Clean or replace sp...

Страница 20: ...over they must be open 4 Removethethreebolts to removethemuffler cover Drop the cover down to inspect the condition of the exhaust ports etc Figure 8 5 Pullthestarterropeuntilthepistoncoversthe exhaus...

Страница 21: ...owered Figure 10 By inserting a tube from the carburetor float bowl into the venturi Figure 11 lower air pressure at the venturi draws fuel through the tube The fuel oil mix is then picked up by and m...

Страница 22: ...l line Pull the carburetor assembly down and away from the engine such that the air vane clears the hole in the shroud base Figure 13 7 Removethethrottlecablescrewandnutand disconnect the cable from t...

Страница 23: ...Remove the float shaft float and inlet needle Remove the fuel inlet Viton seat using a short piece of wire or a shot of compressed air Using an awl pierce the Welch plug then carefully remove itso tha...

Страница 24: ...necessary to check float height However always make sure that no liquid is inside the float before reinstalling Figure 19 4 Positionthebowlgasketonthetopedgeofthe carburetor body Carburetor 5 Placebow...

Страница 25: ...torwiththemountingflange facing you and the throttle wide open 2 Presetthegovernorbyturningthecollar so that the window on the collar is 3 4 clicks to the right of the pulse hole LMR 16 Carburetor Ass...

Страница 26: ...orrect components Fuel tank and in line filters must not be plugged Fuel cap vent hole must not be plugged Air filter must be clean and oiled Crankcase seal Crankcase seals must be installed properly...

Страница 27: ...tor adjustment Adjust to 5 8 to 3 4 turnopen Dirt in idle mixture pocket Remove Welch plug and clean I Restricted filter s Seal all Welch plugs Welch plug leaking Clean filter s Engine Surges carburet...

Страница 28: ...ushes through this tube air pressure at the center of the passage is lowered Figure 29 Byinsertingatubefromthecarburetorfloatbowlinto the venturi Figure 30 lower air pressure at the venturi draws fuel...

Страница 29: ...r 5 Disconnectthefuellineandtheprimertubefrom the carburetor fittings Figure 32 Figure 32 6 Pullthecarburetorassemblydownandaway from the engine such that the air vane governor clears the holein the s...

Страница 30: ...hspeedjetfrom the nozzle Primer Start Carburetor Cleaning and 1 Withthecarburetorcompletelydisassembled thoroughly clean all partsin a parts cleaning solution and inspect for wear or deterioration Blo...

Страница 31: ...open position Install the fuel line and primer tube on the appropriate carburetor fittings Check that the choke air vane assembly moves freely Install the air filter element and cover plugs Primer Sta...

Страница 32: ...cedure in Maintenance pages19 and 20 CAUTION Do not operate the engine without a filter element or with a dry element engine life will be shortened Figure38 PRIMER START CARBURETOR TROUBLESHOOTING Eng...

Страница 33: ...lacementof the cap also prevents interference with the starting rope in Zone Start applications The fuel capis a four piece design Figure 40 with an inner sealing disc that is vented to a baffle assem...

Страница 34: ...ke while working around gasoline Release the clamping pliers and drain the fuel into a container designed to receive gasoline 2 If youremovedthefuellinefromthetankoutlet catch the fuel asit drains out...

Страница 35: ...ged or sheared Flywheel magnets demagnetized or weak Ignition System Spark Plug Operation The spark plug ignites the oil fuel mixture by producing a spark just before the piston reaches top dead cente...

Страница 36: ...rk advance assembly etc Figure 44 shows the location of the CD Pack used in the V Engine Figure 44 As the flywheel magnet passes the CD Pack an AC voltage is induced into the charge coil This AC volta...

Страница 37: ...ighten screws to a torque of 100 in Ibs 11 N m Figure 50 Figure51 Figure 50 Ignition System Flywheel Operation The flywheelis connected directlyto the Crankshaft secured by a flywheel key and nut and...

Страница 38: ...Removekeyandcheck its condition 6 Replacecrankshaftand orflywheel if keyway is 7 Checkflywheelforwearandflywheelmagnets Ignition System Flywheel Installation 1 Makesureflywheelkeyway is absolutelycle...

Страница 39: ...is a 3 8 hex while the other three are 5 16 hex Figure 55 Figure 56 5 Removethe two starterengagementdogsand springs Take noteof the positioning of the springs for correctinstallationlater Figure 56 6...

Страница 40: ...ipsshoulder screw Tighten the screwto a torqueof 33 in Ibs 3 7 N m Figure 59 Figure 59 CAUTION Wear gloves for protection while performing proceduresof the next step plate counterclockwise5 turns Inse...

Страница 41: ...6 6 7 9 N m Figure 61 8 Turnthefueltankoverandnoticethe two extruded tabs These tabs match the holes in the rear portionof the shroud and will automatically align the mounting holes of the fuel tank a...

Страница 42: ...aust port When both ports are sealed the remaining travel compresses theair fuel mixture to prepare it for ignition The travel of pistontowards the spark plug is calledthe compression stroke Figure 62...

Страница 43: ...t from the in Ibs 12 13 N m mower as follows 2 Oil Seals 3 page A 2 Visually inspect for 1 Disconnect the spark plug wire 2 Disassemblethe T starterhandle to untiethe 3 Core Plugs 1 page A 2 Visually...

Страница 44: ...igures 67 68 Remove the drivebelt from the pulley belt will stay with the engine as cover is removed Figure 66 7 RemovetheCDPack page41 Note Step 8 covers 93carburetors 94 carburetors have an addition...

Страница 45: ...ngement p n 677389 in the spark plug hole 12 Under the mower deck remove the three 1 2 Engine Disassembly Note In addition to the figures supplementing the engine disassembly in the following paragrap...

Страница 46: ...n 609904 for installation CAUTION Do not attempt to clean any hole with a drill bit An enlarged hole will reduce compression and engine efficiency and 016with 030as the wear limit Engine Reed Valve S...

Страница 47: ...rod 4 Lubricateandassemblebearings letteredside out to Crankshaft and install crankshaft 5 Installrodcap ensurethatmatingmarksare aligned Clean old screws thoroughly and apply Loctite 271 Figure 76 To...

Страница 48: ...install 14 Installcarburetor andgovernorassembly see 15 Install starter and shroud assembly and starter 16 Reconnectfuellinesandelectricalsystemleads 17 Testrunengine flywheel see page 42 page 30 for...

Страница 49: ...ontrolled by a switch The switch is closed when the blade control bail is in the at rest vertical position Figure 81 Lowering the bail to the main mower handle opens the switch Switch leads are connec...

Страница 50: ...uires replacement remove the second screw 9 to remove the brake mounting plate from the engine Pivoting Zone Start Brake Assembly 1 If thebrakemountingplatewasnotremoved from the engine simply reconne...

Страница 51: ...sted below as they appear on the following pages of this section Power Head Exploded View A 2 Ignition and Exhaust Exploded View A 3 Starter and Walbro LMR 16 Carburetor Exploded View A 4 Walbro LMR 1...

Страница 52: ...tor reed 8 Washer head hex screw 4 9 HSH cap screw 2 10 Split liner 2 11 Needle Bearings 12 Upper main bearing 13 Crankshaft Appendix 14 Bearing 15 Connecting rod assembly 16 Retaining ring 17 Wrist p...

Страница 53: ...lf tapping screw 6 Brake switch leadwire 7 Ground strap 8 Insulationstrap 9 Self expanding plastic rivet 2 10 Shoulder screw 11 Brake plate assembly 12 Screw 13 Brake mountingplate 14 Hex washer head...

Страница 54: ...e 5 not used 6 Screw 2 7 Air filter 8 Air filter cover 9 Retainer 10 Lever 11 Screw 12 Washer 13 Throttle spring Appendix 14 Air vane collar 15 Air vane 16 Screw 3 17 Shroud assembly 18 Hex flange nut...

Страница 55: ...Bowl gasket Fuel bowl Bowl retainer gasket Bowl screw Quantity 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 I 12 13 14 15 16 17 Ref No Part No 684286 684285 683783 682782 683778 683777 683781 Description Quanti...

Страница 56: ...Air vane collar 16 Float 5 Throttle spring 17 Float pin 6 Throttle plate 18 Carburetor bowl 7 Cable bracket 19 Screw 4 8 Screw 2 20 Washer 9 Air filter base 21 Main jet 10 Inlet seat 22 Air filter 11...

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