Lawn-Boy M21BMR User Manual

LAWN-BOY M-SERIES WPM SERVICE MANUAL
Table of Contents – Page 1 of 3
INDEX
GENERAL INFORMATION
INTRODUCTION
SAFETY SYMBOLS AND NOTES
2 CYCLE PRINCIPLES OF OPERATION
1ST CYCLE - DOWN STROKE
2ND CYCLE - UP STROKE
MOWER SPECIFICATIONS
ENGINE SPECIFICATIONS
MODEL NUMBER INDENTIFICATION
"M"-SERIES FEATURES
LUBRICATION (OIL)
GASOLINE
TORQUE REFERENCE
STORAGE PROCEDURE
REMOVING FROM STORAGE
CARBURETION
OPERATION
AIR FILTERS
CARBURETOR REMOVAL
CARBURETOR DISASSEMBLY
CARBURETOR ASSEMBLY
CARBURETOR INSTALLATION
FRESHLUBE OIL INJECTION
OPERATION
INSTALLATION
ADJUSTMENT
TESTING
CHECK VALVE TEST
GOVERNOR CONTROL AND LINKAGES
OPERATION
ADJUSTMENT
ELECTRICAL SYSTEM
IGNITION SYSTEM
SPARK PLUG
IGNITION TROUBLESHOOTING
INTERLOCK SYSTEM
INTERLOCK SYSTEM TROUBLESHOOTING
ELECTRIC START SYSTEM

Lawn-Boy M21BMR Specifications

General

Engine	Briggs & Stratton
Engine Type	4-Cycle
Starter Type	Recoil
Cutting Width	21 inches
Drive System	Rear Wheel Drive
Wheel Size	8 inches

Summary

GENERAL INFORMATION

SAFETY SYMBOLS AND NOTES

Explanation of safety symbols and warnings used in the manual.

LUBRICATION (OIL)

Proper lubrication procedures and oil types for the engine.

GASOLINE

Recommended fuel types and precautions for gasoline.

TORQUE REFERENCE

Specifications for fastener torque values.

STORAGE PROCEDURE

CARBURETION

FRESHLUBE OIL INJECTION

TESTING

GOVERNOR CONTROL AND LINKAGES

OPERATION

ELECTRICAL SYSTEM

IGNITION SYSTEM

Details on the mower's ignition system.

SPARK PLUG

IGNITION TROUBLESHOOTING

Diagnosing and fixing ignition system issues.

INTERLOCK SYSTEM

How safety interlock switches function.

INTERLOCK SYSTEM TROUBLESHOOTING

Diagnosing and fixing interlock system problems.

ELECTRIC START SYSTEM

Information about the electric start system.

WIRING DIAGRAM

Diagrams showing electrical connections for different models.

STARTER

MANUAL STARTER - TOP MOUNT

ELECTRIC STARTER

BLADE and BLADE HOUSING

BLADE REMOVAL

BLADE SHARPENING

BLADE BALANCING

BLADE INSTALLATION

BLADE RELATED TROUBLESHOOTING

Diagnosing and fixing blade-related issues.

HANDLE and CONTROL REPLACEMENT AND ADJUSTMENTS

THROTTLE CONTROL CABLE

SELF-PROPELLED CABLE

FLYWHEEL BRAKE CABLE (ZONE START MODELS)

GEAR SELECT CABLE

BLADE BRAKE CLUTCH (BBC) CABLE

HANDLE REPLACEMENT

DRIVE SYSTEM

DRIVE BELT REPLACEMENT

FLYWHEEL BRAKE SYSTEM

BLADE BRAKE CLUTCH (BBC)

OPERATION

How the BBC system operates.

REMOVAL

INSTALLATION

ADJUSTMENT

ENGINE TROUBLE SHOOTING

Engine Fails to Start or Starts with Difficulty

Diagnosing and fixing starting issues.

Difficulty Starting Engine when Hot

Troubleshooting hot-start problems.

Engine Knocks

Diagnosing and resolving engine knocking.

Engine Misses Under Load

Troubleshooting engine misfiring under load.

Engine Lacks Power

Diagnosing and fixing engine power loss.

Engine Overheats

Troubleshooting engine overheating issues.

Engine Surges or Runs Unevenly

Diagnosing and fixing engine surging or rough running.

Engine Vibrates Excessively

Troubleshooting excessive engine vibration.