Toro 38409, 38412, 38413, 38414, 38417 Service Manual

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R-TEK/DURAFORCE (E) ENGINE SERVICE MANUAL

Table of Contents – Page 1 of 1

PREFACE SAFETY SPECIFICATIONS SPECIAL TOOLS TROUBLESHOOTING MAINTENANCE CARBURETOR FUEL SYSTEM IGNITION SYSTEM REWIND STARTER ENGINE PIVOTING ZONE START BRAKE ELECTRIC START SYSTEM (120 VOLT) ELECTRIC START SYSTEM (12 VOLT)

PREFACE

ABOUT THIS MANUAL

This manual was written expressly for the E series engines. There are two engines in this series. One is piston ported (R tek) and the other is a reed valve (DuraForce). As these en covered here. Where there are differences between the two versions, a headin discussed. We have made every effort to make this information complete and correct.

We hope that you find this manual a valuable addition to your service shop. If you have questions or comments re

arding this manual, please contact us at the following address:

The Toro Company Consumer Service Department 8111 Lyndale Ave. So. Minneapolis, MN 55420-1196

ines are of the same family, they will both be

will state which engine is being

The Toro Company reserves the ri

ht to change product specifications or this manual without notice.

TABLE OF CONTENTS

SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

ine Specifications (All dimensions are for a new engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

En En

ine Fastener Torque Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Standard Torques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Carburetor Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

SPECIAL TOOL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

ine Will Not Start When “Cold” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

ine Will Start When “Cold”, But Not When “Hot” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

ine Will Not Produce Spark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

ine Flooded With Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

ine Has Low Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

ine Lacks Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

ine Surges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

ine Backfires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

ine Overheats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

ine Vibrates Excessively . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

ine Crankshaft Will Not Turn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

ine Produces Mechanical Knocking Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

ine Pre-Ignites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

ine Smokes Excessively (Smoke is light colored, engine runs well) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

ine Smokes Excessively (Smoke is dark, engine runs poorly) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

ine Stalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Spark Plu

MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Fouled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Recommended Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Air Filter (Mower Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Spark Plu Cleanin Cleanin Reassemblin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

the Exhaust System (Lawn Mower) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

the Exhaust System (Snowthrower) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Exhaust System (Mower Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

TABLE OF CONTENTS

CARBURETOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Troubleshootin

Preliminary Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Removal of DuraForce Carburetor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Removal of R tek Carburetor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Cleanin

Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Governor Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Fuel Cap Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Reed Valve En Piston Ported En Presettin Servicin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

ine (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

ine (R tek Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

the Governor (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

the Air Filter (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Cleanin

IGNITION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Troubleshootin Testin Spark Plu Spark Plu

CD Pack Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

CD Pack Air Gap Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

CD Pack Removal/Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Flywheel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Flywheel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Flywheel Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

TABLE OF CONTENTS

REWIND STARTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Removal and Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Reed Valve En Piston Ported En

Both Piston Ported and Reed Valve En

Service Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Inspection and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Reed Valve Service (DuraForce En

Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Reinstalling External Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Crankshaft Seal Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

PIVOTING ZONE START BRAKE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

ine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

ine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

ines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

ines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

ELECTRIC START SYSTEM (120 VOLT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Troubleshootin

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Starter Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Starter Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Starter Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Starter Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

iii

TABLE OF CONTENTS

ELECTRIC START SYSTEM (12 VOLT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Troubleshootin

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Starter Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Starter Testin

Starter Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

Starter Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Starter Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Alternator Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Alternator Output Testin

Alternator Air Gap Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Alternator Resistance Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Cup Assembly Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

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SAFETY

SAFETY INFORMATION

General

This safety symbol means WARNING or PERSONAL SAFETY INSTRUCTION - read the instruction because it has to do with your safety. Failure to comply with the instruction may result in personal injury or even death.

This manual is intended as a service and repair manual only. The safety instructions provided herein are for troubleshootin information on the complete product powered by the E series en instructions are available throu

Lawn-Boy Corporation / The Toro Company Parts Department 8111 Lyndale Avenue South Bloomin

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

ine. Operator’s manuals with complete

ton, MN 55420 U.S.A.

Safety Tips

Avoid unexpected starting of engine...

Always turn off the powered product and disconnect the spark plu or repair.

Avoid lacerations and amputations...

Stay clear of all movin runnin movin potential to start.

Avoid burns...

.Do not touch the en after it has been runnin

Avoid Falls...

Do not operate the powered product on slippery surfaces or if footin

Avoid fires...

Wipe up any spilled fuel or oil immediately.

Avoid asphyxiation...

Never operate an en proper ventilation.

wire before attempting cleaning, adjustment,

parts whenever the engine is

. Treat all normally moving parts as if they were

whenever the engine is running or has the

ine while it is running or shortly

is questionable.

ine in a confined area without

Avoid accidental misuse of fuel...

Always store fuel in a properly labeled container desi

ned for gasoline.

Avoid injury due to inferior parts...

Use only Toro/Lawn-Boy ori important safety criteria are met.

Avoid injury to bystanders...

Always clear the area of bystanders before startin testin

powered equipment.

Avoid injury due to projectiles...

Always clear the area of sticks, rocks, or any other debris that could be picked up and thrown by the powered equipment. Keep all safety shields in place.

Avoid modifications...

Never alter or modify any part unless it is a factory approved procedure.

Avoid unsafe operation...

Always test the safety systems after makin adjustments or repairs on the machine.

inal parts to ensure that

Avoid fires and explosions...

Use a container desi fuel and never smoke while workin fuel.

ned for gasoline. Avoid spilling

with any type of

SPECIFICATIONS

Specifications

Engine Specifications (All dimensions are for a new engine)

Item DuraForce R tek

Type Reed valve 2-cycle Piston ported 2-cycle

Bore

Stroke

Wrist pin diameter

Crankpin diameter

End play (crankshaft)

Side play (crankshaft) near lower main

Piston cyl. Clearance (tightest loc.)

Wrist pin hole diameter

Bottom ring thickness, new

End gap, new (both rings)

Displacement

2.5000" +

.5000" + .0000 - .0002 (12.70mm + .000 - .005)

.7427" + .0003 - .0002 (18.85mm + .008 - .005)

0 - .017" (0 - .431mm) Walk mower

.0006" + .0003 - .0006 (.015mm + .008 - .015)

.0035" to .0059" (.089 to .150mm)

.500"/.5005" (12.705mm / 12.712mm)

.0600 +

.0005 (63.5mm + .0127)

1.75" (44.45mm)

0 - .017" (0 - .431mm) 1998 Snow 0 - .0215" (0 - .533mm) 1999 and later Snow

.0005 (1.52mm + .013)

.016/.008 in. (.40/.20mm)

8.6 cu in. (141cc)

Horsepower 6.5HP 4 or 5HP

Compression ratio

Compression

Carburetor

Approximately 115 psi. Service limit 80 psi.

Dual-circuit Lawn-Boy with fixed jets, float type with primer and choke

5.8:1

Fuel required

Unleaded regular (87 octane R+M/2):2-cycle oil

Mix ratio 32:1 50:1 Recommended Oil .Lawn-Boy Generation II 2-cycle

oil or NMMA TCW3 Toro 2-cycle oil or NMMA TCW3

Fuel tank capacity

Ignition type

CD Pack air gap

Spark plug / air gap

Solid-state CD Pack, magneto type

NGK projected nose / NGK BPMR4A .030" (.76mm)

Varies with product

.010" (.25mm)

Start system Rope rewind or 12 VDC Rope rewind or 120 VAC

Governor

Governed Engine Speed

2900 +

300 rpm

Air vane

4HP runs at 3700 + CCR 2400 - 3700 5HP runs at 3800 + CCR 2450 & 2500 - 3800 rpm

CCR 3600 - 3900 rpm CCR 3650 - 4000 rpm Snow Commander - 4000 rpm All snow engines are +

300

300 rpm

Idle Speed 2200 - 2800 rpm N/A

ir Cleaner .Oiled foam type with Centrifugal

pre-cleaner N/A

SPECIFICATIONS

Item DuraForce R tek

Choke Manual, butterfly type Fuel filter In-tank and in-carburetor Piston rin

Piston Permanent mold, hi

s Cast iron, semi-keystone top ring. Second ring is rectangular.

Anti-rotation pin in piston.

h silicon aluminum

Engine Fastener Torque Requirements

Item DuraForce R tek

Bolt, Head 140 - 200 in. lbs. (16 - 22 Nm) 140 - 200 in. lbs. (16 - 22 Nm) Jet, Main 4 - 6 in. lbs. (.44 - .66 Nm) 4 - 6 in. lbs. (.44 - .66 Nm) Jet, Pilot* 10 - 12 in. lbs. (1.1 - 1.3 Nm) 6 - 8 in. lbs. (.66 - .88 Nm)* Nozzle, Carburetor* 16 - 28 in. lbs. (1.7- 4.0 Nm) 20 - 30 in. lbs. (2.2 - 3.4 Nm) Nut, Blade 45 - 50 ft. in. (60 - 67 Nm) NA Nut, Flywheel 375 - 425 in. lbs. (42 - 47 Nm) 375 - 425 in. lbs. (42 - 47 Nm) Seat, Float Valve* 16 - 28 in. lbs. (1.7 - 4.0 Nm) 22-32 in. lbs. (2.4 - 3.5 Nm) Screw, Brake Plate Assembly 60 - 70 in. lbs. (6.7 - 7.8 Nm) NA Screw, Carburetor Mountin

g 20 - 30 in. lbs. (2.2 - 3.4 Nm) 20 - 30 in. lbs. (2.2 - 3.4 Nm) Screw, CD I Screw, Cylinder to Crankcase 55 - 90 in. lbs. (6.2 - 10.0 Nm) 55 - 90 in. lbs. (6.2 - 10.0 Nm) Screws, En Screw, Float Bowl 10 - 13 in. lbs. (1.1 - 1.5 Nm) 10 - 13 in. lbs. (1.1 - 1.5 Nm) Screw, Muffler (611228) 55 - 90 in. lbs. (6.2 - 10.0 Nm) 55 - 90 in. lbs. (6.2 - 10.0 Nm) Screw, Muffler Cover 55 - 90 in. lbs. (6.2 - 10.0 Nm) NA Screw, Muffler Plate 140 - 200 in. lbs. (16 - 22 Nm) NA Screw, Reed 10 - 13 in. lbs. (1.1 - 1.5 Nm) NA Screw, Rod Cap to Rod 65 - 75 in. lbs. (7.3 - 8.4 Nm) 65 - 75 in. lbs. (7.3 - 8.4 Nm) Screw, Shroud 58 - 70 in. lbs. (6.5 - 7.8 Nm) 58 - 70 in. lbs. (6.5 - 7.8 Nm) Screw, Shroud Base 58 - 70 in. lbs. (6.5 - 7.8 Nm) 58 - 70 in. lbs. (6.5 - 7.8 Nm) Spark Plu Rewind Starter to blower housing NA 20-30 in. lbs. (2.2 - 3.4 Nm) Screw, Manifold NA 55 - 70 in. lbs. (6.2 - 7.8 Nm) Screw, Muffler NA 100 - 130 in. lbs.

gnition Pack 90 - 110 in. lbs. (10 - 12 Nm) 90 - 110 in. lbs. (10 - 12 Nm)

gine Mounting 170 - 220 in. lbs. (19 - 25 Nm) 170 - 220 in. lbs. (19 - 25 Nm)

g 150 - 200 in. lbs. (17 - 23 Nm) 150 - 200 in. lbs. (17 - 23 Nm)

* Overtorquin

g will crack the carb body and cause the engine to run rich page rev 8/06

SPECIFICATIONS

Item DuraForce R tek

Nut, Shroud 100 - 130 in. lbs. (10 - 14 Nm) 140 - 170 in. lbs. (16 - 19 Nm) Screw, Starter Bracket to Recoil NA 30 - 35 in. lbs. (3.4 - 3.8 Nm) Screw, Gov Pivot Block to Cyl. NA 30 - 35 in. lbs. (3.4 - 3.8 Nm) Screw, Elect Start to Crankcase 140 - 200 in. lbs. (16 - 22 Nm) 75 - 100 in. lbs. (8.2 - 11 Nm)

Standard Torques

Size US (Metric)

#10 - 24 20 - 30 in. lbs. (5.1 - 6.21 Nm) 1/4 - 20 55 - 90 in. lbs. (6.2 - 10.0 Nm) 5/16 - 18 140 - 200 in. lbs. (16 - 22 Nm)

Carburetor Specifications

Item DuraForce R tek

Type Lawn-Boy, float type, dual-circuit, with primer and choke Body Material Minlon Seat material Brass with Viton tipped needle. Both are replaceable. Inlet Needle “Pop-Off” Pressure 5 psi (.7 k Main Jet 77.5 73.8 Main Nozzle Brass Pilot Jet 37.5 42.5

h Altitude NA

Hi Float Adjustment Float hei

ht .500 ± .030" bowl flange (no gasket) to top of float

/cm2) (Wet)

SPECIAL TOOL REQUIREMENTS

Listing

Description Order From Part Number Comments/Use

SPECIAL TOOLS

Air Gap Gau

Piston Ring CompressorOTCTOR 4089Compresses piston rings to allow installation

Wrist Pin Knockout Tool Toro 602884 Used to drive wrist pin out of piston

OTC Tool & Equipment Division SPX Corporation Industrial Park 2013 4th Street NW Owatonna, MN 55060 Telephone: 800-533-0492 Fax: 507-455-7011

e Toro 604659 Sets .010” (.25 mm) gap between flywheel

and coil

into the cylinder

TROUBLESHOOTING

Engine Will Not Start When “Cold”

Possible Causes Remedies

Fuel tank is empty Fill with clean, fresh, properly-mixed, unleaded fuel Bad fuel Drain tank and float bowl. Fill the tank with clean, fresh,

unleaded, properly-mixed fuel. Fuel filter plu Air cleaner plu Fouled spark plu No spark at spark plu Insufficient momentum Check for loose blade, mower only Incorrect i Low compression See “En

ine flooded with fuel See “Engine Flooded With Fuel” table

En Reed valves not closed Replace reed valves (DuraForce only) Reed valves stuck closed Free up and run en Primer or choke not operatin

ed Replace fuel tank

ed Wash and re-oil air cleaner element (DuraForce only)

Remove and replace the spark plu

See “Engine Will Not Produce Spark” table

nition timin

Check for sheared flywheel key

ine Has Low Compression” table

ine to clean (DuraForce only)

Fix or replace

Engine Will Start When “Cold”, But Not When “Hot”

Possible Causes Remedies

ine is flooded See “Engine Flooded With Fuel” table

Excessive alcohol in fuel Use no more than 10% ethanol blend. Avoid methanol

ine is overheated See “Engine Overheats” table

ed bowl vent Clean bowl vent

Clo Fuel percolation (vapor lock) Use current season

as for fuel mixture

Engine Will Not Produce Spark

Possible Causes Remedies

TROUBLESHOOTING

Spark plu Spark plu Spark plug wire damaged Replace CD pack Coil kill wire

nition coil failed Replace CD pack

I Flywheel ma

wire disconnected Reconnect spark plug wire fouled or damaged Replace spark plu

rounded Locate and eliminate the unwanted ground

nets weak Replace flywheel

Engine Flooded With Fuel

Possible Causes Remedies

Overuse of choke position Take throttle off choke Throttle cable misadjusted Adjust throttle cable, if present Air cleaner plu Fouled spark plu Carburetor inlet needle stuck open or leakin

ed Wash and re-oil air cleaner element (DuraForce only)

Replace spark plu Clean carburetor, replace failed parts, and pressure test

Carburetor Air Vent Clean Air Vent

Engine Has Low Compression

Possible Causes Remedies

Worn piston rin Piston rin Cylinder worn Remove and replace short block

s Replace piston rings or short block

(s) stuck in groove Replace piston and rings

TROUBLESHOOTING

Engine Lacks Power

Possible Causes Remedies

Dull blade Sharpen or replace blade, mower only Housin Plu Muffler plu Flywheel key sheared Replace flywheel key Carburetor dirty Clean carburetor Intake air leak Repair or replace failed components(s) Low compression See “En

choked with grass and debris Clean housing thoroughly, mower only

ed exhaust system Clean exhaust ports

ed Clean or replace muffler

ine Has Low Compression” table

Engine Surges

Possible Causes Remedies

Fouled idle circuit Clean idle circuit Air leak Check sealin Restricted fuel flow Check filters and fuel line

ine RPM low Adjust to proper specification. Note: A slight surge at no

load is normal.

surfaces, oil seals, gaskets, and port plugs

Governor link misadjusted (R tek) Adjust Air vane stickin

Clean or replace

Engine Backfires

Possible Causes Remedies

Flywheel key sheared Replace key Muffler filled with carbon Clean muffler Exhaust ports plu Air leak to crankcase Replace seals or re-seal crankcase to cylinder Spark plu

partly fouled Clean or replace

ed Clean ports

Engine Overheats

Possible Causes Remedies

TROUBLESHOOTING

Cylinder head coolin Restricted carburetor jets Clean carburetor and jet Improper Coolin

as to oil mix ratio Ensure mixture is correct

air intake plugged Remove foreign material and clean

fins clogged Clean fins thoroughly

Engine Vibrates Excessively

Possible Causes Remedies

Blade out of balance Balance blade or replace if dama Bent blade Replace blade Loose en

Bent crankshaft Replace crankshaft Flywheel out of balance (dama

ine mounting screws Tighten engine mounting screws (engine to plate, plate

to mower housin

ed) Replace flywheel

)

Engine Crankshaft Will Not Turn

Possible Causes Remedies

ine brake incorrectly engaged Disengage brake and inspect and repair as necessary,

mower only Blade jammed in housin Piston seized in its cylinder Inspect and repair or replace Starter jammed Repair starter

Inspect and repair or replace, mower only

Engine Produces Mechanical Knocking Sound

Possible Causes Remedies

Loose blade Inspect and ti

only Loose flywheel Inspect and ti

nition is occurrin

Pre-i Loose rod cap Replace rod and bearin

See “Engine Pre-Ignites” table

hten blade nut to correct torque, mower

hten flywheel nut to correct torque

Loose en

ine mounting bolts Tighten bolts

TROUBLESHOOTING

Engine Pre-Ignites

Possible Causes Remedies

Wron

spark plug - too hot Install the correct type of spark plu Low quality fuel (old or stale) Replace with fresh, unleaded regular fuel Carbon buildup in en Excessive alcohol in fuel Replace with fresh unleaded fuel havin

Sheared flywheel key Inspect and repair

ine Decarbon engine and muffler

no more than

10% ethanol

Engine Smokes Excessively (Smoke is light colored, engine runs well)

Possible Causes Remedies

Sli

ht oil accumulation in crankcase None; normal on start-up

Air cleaner element clo

Fuel/oil mixture too rich Drain fuel tank and fill with fuel of correct mixture Choke is in “On” position Move to hi

ed Clean and re-oil or replace air cleaner element, mower

only

h speed or “Off” position

Engine Smokes Excessively (Smoke is dark, engine runs poorly)

Possible Causes Remedies

Carburetor runnin Choke is in “On” position Move to hi

too rich Clean and check carburetor

h speed or “Off” position

TROUBLESHOOTING

Engine Stalls

Possible Causes Remedies

ine out of fuel Refill with fresh fuel of the correct mixture ine overloaded Unload engine and restart

En Fuel filter plu Spark plu Fuel cap vent plu

nition inadvertently grounded Inspect and repair to remove unwanted ground

I Carburetor vent plu

ine overheated Clear debris from fins or cause of overheatin

En Improper lubrication Tear down and inspect for damage

ed Clean fuel filter/tank

fouled See “Spark Plug Fouled” table

ed Replace fuel cap

ed Clear vent of obstruction

Spark Plug Fouled

Possible Causes Remedies

Incorrect spark plu Carburetor running too rich Clean/rebuild carburetor

ed air cleaner element Clean and re-oil element or replace, mower only

Clo Overuse of “choke” position Move control off “choke” position and check throttle

Use correct spark plu

cable adjustment Weak i Worn rin Use of poor fuel Drain fuel tank and replace with fresh, unleaded re

Fuel/oil mixture too rich Drain fuel tank and fill with fuel of correct mixture Wron

nition system Replace CD ignition pack

s and/or cylinder Rebuild engine or short block

fuel havin

Oil Use Toro 2-cycle oil, Lawn-Boy DuraForce oil, or

NMMA TCW3 approved oil

the correct oil mixture

ular

THIS PAGE INTENTIONALLY LEFT BLANK

Recommended Maintenance Schedule

Frequency Item Comments

MAINTENANCE

5 Hours Fasteners Check blade and en

frequently. Keep all nuts, bolts, and screws ti

ht to ensure safe operation.

25 Hours Housin

Spark Plu

50 Hours Air Filter (Mower only.) Remove and clean each

Blade

Blade Brake

(Mower only.) Remove the buildup of grass clippin

(Self-propelled mower only.) Clean clippin mechanism cover and drive belt.

Clean, inspect, and regap; replace if necessary.

mowin frequently if operatin

(Mower only.) Sharpen or replace; maintain more frequently if ed rou

Check stoppin of each mowin within 3 seconds of releasin repair or replace.

s and dirt.

s and debris under drive belt

season or every 50 hours; more

h or sandy conditions.

ine mounting fasteners

rass

conditions are dusty.

e is dulled quickly in

time every 50 hours or at start

season. Blade must stop

bail. If not,

Lubrication (Self-propelled mowers only.) Grease rear

Exhaust Ports Clean every 50 hours or at least once each

Fuel System Check for leaka

100 Hours Coolin

hei

ht adjuster brackets.

season.

e and/or deterioration of fuel

hose. Replace if necessary.

System Clean grass clippings, debris, or dirt that clog

ine air cooling fins; clean more frequently

under dirty or hi

h chaff conditions.

+ 45 hidden pages