Lawn-Boy V-Engine User manual

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

LAWN-BOY V-ENGINE SERVICE MANUAL

Table of Contents – Page 2 of 2

SECTION 3 FUEL SYSTEM

FUEL SYSTEM - OPERATION

FUEL SYSTEM - CAP SERVICE

FUEL SYSTEM - TANK REMOVAL

FUEL SYSTEM - CLEANING

FUEL SYSTEM - TANK INSTALLATION

SECTION 4 IGNITION SYSTEM

IGNITION SYSTEM - TROUBLESHOOTING

IGNITION SYSTEM - SPARK PLUG OPERATION

IGNITION SYSTEM - SPARK PLUG SERVICE

IGNITION SYSTEM - CD PACK OPERATION

IGNITION SYSTEM - CD PACK AIR GAP ADJUSTMENT

IGNITION SYSTEM - CD PACK REMOVAL/INSTALLATION

IGNITION SYSTEM - FLYWHEEL OPERATION

IGNITION SYSTEM FLYWHEEL REMOVAL

IGNITION SYSTEM - FLYWHEEL INSTALLATION

SECTION 5 REWIND STARTER

REWIND STARTER - OPERATION

REWIND STARTER - REMOVAL AND DISASSEMBLY

REWIND STARTER - REASSEMBLY

SECTION 6 ENGINE

ENGINE - DESCRIPTION

ENGINE - THEORY OF OPERATION

ENGINE - SERVICE TIPS

ENGINE - REMOVAL

ENGINE - DISASSEMBLY

ENGINE - INSPECTION AND REPAIR

ENGINE - REED VALVE SERVICE

ENGINE - REASSEMBLY

SECTION 7 PIVOTING ZONE START BRAKE

INTRODUCTION

PIVOTING ZONE START BRAKE - OPERATION

PIVOTING ZONE START BRAKE - DISASSEMBLY

PIVOTING ZONE START BRAKE - ASSEMBLY

APPENDIX A

V-Engine

TABLE

CONTENTS

Reference Section

Safety Information

Engine Specifications 10

Engine Fastener Torque Requirements 11

Carburetor Specifications 12

Special Tool Requirements 13

Troubleshooting 14

Maintenance 19

Recommended Maintenance Schedule 19

Air Filter 19

Spark Plug 20

Cleaning the Exhaust System 21

Service Section

Section1 LMR-16

Carburetor

Identification 25

Theory of Operation 25

Governor Theory 25

Removal 26

Disassembly 27

Cleaning and Inspection 27

Assembly 28

Presetting the Governor 29

Assembling Air Box to Carburetor 29

Installation 30

FinalCheck 30

Choke Adjustment 30

Servicing the Air Filter

Troubleshooting 31

V-Engine

Table

Contents

TABLE

CONTENTS

Service Section (cont'd)

Section

PrimerStartCarburetor

Identification 32

Theory

Operation 32

Governor The0

Removal 33

Disassembly 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 Service 37

Tank Removal 38

Cleaning 38

Tank

installation

Ignition System

Troubleshooting 39

Spark Plug

Operation 39

Service 39

V-Engine Table

Contents

TABLE

CONTENTS

ServiceSection(cont’d)

Section 4 (cont’d)

CD Pack

Operation 40

Air Gap Adjustment 41

Removal Installation 41

Flywheel

Operation 41

Removal 41

Installation 42

Section

Section 6

Rewind Starter

Operation 43

Removal and Disassembly 43

Reassembly 44

Engine

Description

.........................................................

Theory

Operation ............................................................................................

Service Tips

........................................................................................................

Removal..............................................................................................................

Disassembly........................................................................................................

Inspection and Repair

..............................................................................

Reed Valve Service

..................................................................................

Reassembly.........................................................................................................

V-EngineTable

Contents

TABLE

CONTENTS

Service Section (cont’d)

Section

PivotingZoneStartBrake

Introduction

Operation

Disassembly 53

Assembly

Appendix A

Exploded View Diagrams A-1

Table

Contents

V-Engine

SAFETY INFORMATION

ThissafetysymbolmeansWARNINGorPERSONALSAFETYINSTRUCTIONreadtheinstruction

because it has to do with your safety. Failure to comply with the instruction may result in personal injury

This manualis intended as a service and repair manual only. The safety instructions provided herein are for trou-

bleshooting, service and repair of the engine only. The individual Operator’s manual will contain safety information

on the complete product powered by the

engine. Operator’s manuals with complete instructions are available

through:

or even death.

Lawn-Boy Corporation

Publications Department

8111

Lyndale Avenue South

Bloomington,

55430

U.S.A.

SAFETY TIPS

Avoid unexpected startingof engine

Always turn

off

the powered product and disconnect

spark plug wire before attempting cleaning, adjust-

ment or repair.

Avoid lacerations and amputations

Stay clear of all moving parts whenever the engineis

running. Treat all normally moving parts as

they

were moving whenever the engine

runningor has

Avoid burns

not touch the engine whileit is running or shortly

after it has been running.

Avoid Falls

thepotential to start.

Avoid asphyxiation

Never operate an enginein a confined area without

proper ventilation.

Avoid fires and explosions

Use a container designed for gasoline. Avoid spilling

fuel and never smoke while working with any typeof

fuel.

Avoid accidental misuseof fuel

Always stolefuel in a properly labeled container

designed for gasoline.

Avoid injury dueto inferior parts

Use only Lawn-Boy@ original partsto ensure that

important safety criteria are met.

Do not operate the powered product on slippery sur-

faces or

footing isquestionable.

Avoid

injuryto bystanders

Always clear the area of bystanders before starting or

Avoid fires

Wipe up any spilled fuel oroil immediately. testing powered equipment.

Avoid injury due

projectiles

Always clear the areaof sticks, rocks or any other

debris that could be picked up and thrown by the

powered equipment.

ReferenceSection

SafetyInformation

Engine Specifications

Bore2.3810 2.3800 (60.47785.852mm)

Stroke1.75201.7497”(44.50144.442mm)

Connectingrodlength 3.00 (76.2mm)

Wrist pin diameter

.5000”

(12.7 mm)

Wrist pin offset

.070

(1.78 mm) toward major thrust side

Crankpin diameter .742”(18.85 mm)

Top and bottom main bearings Dia:Top:.875”(22.23mm)Bottom:1.125”(28.58mm)

Displacement 7.78 cu in (127.51 cc)

Horsepower 4.5

Compressionratio 5.91:l (Rangeof5.151 6.668:l)

Carburetor ‘93 models

Carburetor ‘94 models up)

Fuel required

Recommendedoil

Fuel tank 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(87octane2-cycleoil

Lawn-Boy Ashless 2-cycle oil

1.5 quarts

Solid state CD Pack, magneto type

.010(.25 mm)

2’8’ BTDC (Cranking);22’ 28’ (Running)

__-

--_-

SparkplugairgapChampionRJ12C .035 (.889mm)

Starting system

GovernorAirvane Rope rewind

Governedenginespeed

Idlespeed 3050+/- 100 RPM

2200 2800 RPM

Aircleaner

Choke

Fuel filter

Oiled, foam type

Manual, butterfly type (Walbro only)

ln-tank and in-carburetor

PistonPermanentmold,highsiliconaluminum

PistonringsCastiron,semi-keystonetopring

Reference Section

SPECIFICATIONS

(cont'd)

Engine Fastener Torque Requirements

* Use thread-locking compound

Reference Section

Torque

45 50

Ibs

(60 67 N-m)

375 425

lbs

(42 47 N-m)

Ibs

(.5 .8 N-m)

60 70

Ibs

(6.7 7.8 N-m)

55 in

Ibs

(5.0 6.1 N-m)

90 110

Ibs

(10 12 N-m)

105 115

Ibs

(12 13 N-m)

300 350

Ibs

(34 39 N-m)

15 25

Ibs

(1.7 2.8 N-m)

150 190

Ibs

(17 22 N-m)

140 200

Ibs

(16 22 N-m)

10 13

Ibs

(1.1 1.5 N-m)

65 75

Ibs

(7.3 8.4 N-m)

58 70

Ibs

(6.5 7.8 N-m)

60 70

Ibs

(6.7 7.8 N-m)

150 200

Ibs

(17 23 N-m)

65.15

Ibs

(7.3 8.4 N-m)

-__I_-----~-

Specifications

Table of contents

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