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

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 engines are of the same family, they will both be covered here. Where there are differences between the two versions, a heading will state which engine is being 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 regarding this manual, please contact us at the following address:

The Toro Company

Consumer Service Department

8111 Lyndale Ave. So.

Minneapolis, MN 55420-1196

The Toro Company reserves the right to change product specifications or this manual without notice.

TABLE OF CONTENTS

TABLE OF CONTENTS

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

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

Engine Specifications (All dimensions are for a new engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	2
Engine Fastener Torque Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
Standard Torques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
Carburetor Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4

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

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

Engine Will Not Start When “Cold” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . 6
Engine Will Start When “Cold”, But Not When “Hot” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . .6
Engine Will Not Produce Spark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .7
Engine Flooded With Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .7
Engine Has Low Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .7
Engine Lacks Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .8
Engine Surges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .8
Engine Backfires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .8
Engine Overheats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .9
Engine Vibrates Excessively . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .9
Engine Crankshaft Will Not Turn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .9
Engine Produces Mechanical Knocking Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . .9
Engine Pre-Ignites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . .10
Engine Smokes Excessively (Smoke is light colored, engine runs well) . . . . . . . . . . . . . . . . . . . . . . . . . .	. . .10
Engine Smokes Excessively (Smoke is dark, engine runs poorly) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . .10
Engine Stalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . .11
Spark Plug Fouled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . .11

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

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

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

Spark Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

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

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

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

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TABLE OF CONTENTS

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

Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Preliminary Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Removal of DuraForce Carburetor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 Removal of R tek Carburetor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 Cleaning and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 Governor Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Reed Valve Engine (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Piston Ported Engine (R tek Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Presetting the Governor (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Servicing the Air Filter (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

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

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

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

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

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

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Spark Plug Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Spark Plug Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

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

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

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

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

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

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

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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 Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Piston Ported Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

Both Piston Ported and Reed Valve Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

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

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

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

Reed Valve Service (DuraForce Engines Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

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

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

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

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

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

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

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

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

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

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

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

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

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

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

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

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

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

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

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

Starter Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

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

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

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

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

Alternator Output Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

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

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

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

iv

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 troubleshooting, service, and repair of the engine only. The individual Operator’s manual will contain safety information on the complete product powered by the E series engine. Operator’s manuals with complete instructions are available through:

Lawn-Boy Corporation / The Toro Company

Parts Department

8111 Lyndale Avenue South

Bloomington, MN 55420 U.S.A.

Safety Tips

Avoid unexpected starting of engine...

Always turn off the powered product and disconnect the spark plug wire before attempting cleaning, adjustment, or repair.

Avoid accidental misuse of fuel...

Always store fuel in a properly labeled container designed for gasoline.

Avoid injury due to inferior parts...

Avoid lacerations and amputations...

Stay clear of all moving parts whenever the engine is running. Treat all normally moving parts as if they were moving whenever the engine is running or has the potential to start.

Avoid burns...

Use only Toro/Lawn-Boy original parts to ensure that important safety criteria are met.

Avoid injury to bystanders...

Always clear the area of bystanders before starting or testing powered equipment.

.Do not touch the engine while it is running or shortly after it has been running.

Avoid Falls...

Do not operate the powered product on slippery surfaces or if footing is questionable.

Avoid fires...

Wipe up any spilled fuel or oil immediately.

Avoid asphyxiation...

Never operate an engine in 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 type of fuel.

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 making adjustments or repairs on the machine.

1

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	2.5000" + .0005 (63.5mm + .0127)
Stroke	1.75" (44.45mm)
Wrist pin diameter	.5000" + .0000 - .0002 (12.70mm + .000 - .005)
Crankpin diameter	.7427" + .0003 - .0002 (18.85mm + .008 - .005)
End play (crankshaft)	0 - .017" (0 - .431mm) Walk mower	0 - .017" (0 - .431mm) 1998 Snow
		0 - .0215" (0 - .533mm) 1999 and
		later Snow
Side play (crankshaft) near lower main	.0006" + .0003 - .0006 (.015mm + .008 - .015)
Piston cyl. Clearance (tightest loc.)	.0035" to .0059" (.089 to .150mm)
Wrist pin hole diameter	.500"/.5005" (12.705mm / 12.712mm)
Bottom ring thickness, new	.0600 + .0005 (1.52mm + .013)
End gap, new (both rings)	.016/.008 in. (.40/.20mm)
Displacement	8.6 cu in. (141cc)
Horsepower	6.5HP	4 or 5HP
Compression ratio	5.8:1
Compression	Approximately 115 psi. Service limit 80 psi.
Carburetor	Dual-circuit Lawn-Boy with fixed jets, float type with primer and choke
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	Varies with product
Ignition type	Solid-state CD Pack, magneto type
CD Pack air gap	.010" (.25mm)
Spark plug / air gap	NGK projected nose / NGK BPMR4A .030" (.76mm)
Start system	Rope rewind or 12 VDC	Rope rewind or 120 VAC
Governor	Air vane
		4HP runs at 3700 + 300
Governed Engine Speed	2900 + 300 rpm	CCR 2400 - 3700
		5HP runs at 3800 + 300 rpm
		CCR 2450 & 2500 - 3800 rpm
		CCR 3600 - 3900 rpm
		CCR 3650 - 4000 rpm
		Snow Commander - 4000 rpm
		All snow engines are + 300 rpm
Idle Speed	2200 - 2800 rpm	N/A
Air Cleaner	Oiled foam type with Centrifugal
	pre-cleaner	N/A

2

					SPECIFICATIONS
	Item		DuraForce		R tek
	Choke		Manual, butterfly type
	Fuel filter		In-tank and in-carburetor
	Piston rings		Cast iron, semi-keystone top ring. Second ring is rectangular.
			Anti-rotation pin in piston.
	Piston		Permanent mold, high 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 Mounting	20	- 30 in. lbs. (2.2 - 3.4 Nm)	20 - 30 in. lbs. (2.2 - 3.4 Nm)
	Screw, CD Ignition Pack	90	- 110 in. lbs. (10 - 12 Nm)	90 - 110 in. lbs. (10 - 12 Nm)
	Screw, Cylinder to Crankcase	55	- 90 in. lbs. (6.2 - 10.0 Nm)	55 - 90 in. lbs. (6.2 - 10.0 Nm)
	Screws, Engine Mounting	170 - 220 in. lbs. (19 - 25 Nm)		170 - 220 in. lbs. (19 - 25 Nm)
	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 Plug	150 - 200 in. lbs. (17 - 23 Nm)		150 - 200 in. lbs. (17 - 23 Nm)
	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.
	* Overtorquing will crack the carb body and cause the engine to run rich				page rev 8/06

3

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 g/cm2) (Wet)
	Main Jet	77.5		73.8
	Main Nozzle		Brass
	Pilot Jet	37.5		42.5
	High Altitude		NA
	Float Adjustment	Float height .500 ± .030" bowl flange (no gasket) to top of float

4

						SPECIAL TOOLS
SPECIAL TOOL REQUIREMENTS
Listing
	Description			Order From	Part Number	Comments/Use
	Air Gap Gauge			Toro	604659	Sets .010” (.25 mm) gap between flywheel
						and coil
	Piston Ring Compressor			OTC	TOR 4089	Compresses piston rings to allow installation
						into the cylinder
	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: [phone]
	Fax:	507-455-7011

5

TROUBLESHOOTING

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 plugged	Replace fuel tank
	Air cleaner plugged	Wash and re-oil air cleaner element (DuraForce only)
	Fouled spark plug	Remove and replace the spark plug
	No spark at spark plug	See “Engine Will Not Produce Spark” table
	Insufficient momentum	Check for loose blade, mower only
	Incorrect ignition timing	Check for sheared flywheel key
	Low compression	See “Engine Has Low Compression” table
	Engine flooded with fuel	See “Engine Flooded With Fuel” table
	Reed valves not closed	Replace reed valves (DuraForce only)
	Reed valves stuck closed	Free up and run engine to clean (DuraForce only)
	Primer or choke not operating	Fix or replace

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

	Possible Causes	Remedies
	Engine is flooded	See “Engine Flooded With Fuel” table
	Excessive alcohol in fuel	Use no more than 10% ethanol blend. Avoid methanol
	Engine is overheated	See “Engine Overheats” table
	Clogged bowl vent	Clean bowl vent
	Fuel percolation (vapor lock)	Use current season gas for fuel mixture

6

		TROUBLESHOOTING
Engine Will Not Produce Spark
	Possible Causes	Remedies
	Spark plug wire disconnected	Reconnect spark plug wire
	Spark plug fouled or damaged	Replace spark plug
	Spark plug wire damaged	Replace CD pack
	Coil kill wire grounded	Locate and eliminate the unwanted ground
	Ignition coil failed	Replace CD pack
	Flywheel magnets 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 plugged	Wash and re-oil air cleaner element (DuraForce only)
	Fouled spark plug	Replace spark plug
	Carburetor inlet needle stuck open or leaking	Clean carburetor, replace failed parts, and pressure test
	Carburetor Air Vent	Clean Air Vent
Engine Has Low Compression
	Possible Causes	Remedies
	Worn piston rings	Replace piston rings or short block
	Piston ring(s) stuck in groove	Replace piston and rings
	Cylinder worn	Remove and replace short block

7

TROUBLESHOOTING

Engine Lacks Power

	Possible Causes	Remedies
	Dull blade	Sharpen or replace blade, mower only
	Housing choked with grass and debris	Clean housing thoroughly, mower only
	Plugged exhaust system	Clean exhaust ports
	Muffler plugged	Clean or replace muffler
	Flywheel key sheared	Replace flywheel key
	Carburetor dirty	Clean carburetor
	Intake air leak	Repair or replace failed components(s)
	Low compression	See “Engine Has Low Compression” table

Engine Surges

	Possible Causes	Remedies
	Fouled idle circuit	Clean idle circuit
	Air leak	Check sealing surfaces, oil seals, gaskets, and port plugs
	Restricted fuel flow	Check filters and fuel line
	Engine RPM low	Adjust to proper specification. Note: A slight surge at no
		load is normal.
	Governor link misadjusted (R tek)	Adjust
	Air vane sticking	Clean or replace

Engine Backfires

	Possible Causes	Remedies
	Flywheel key sheared	Replace key
	Muffler filled with carbon	Clean muffler
	Exhaust ports plugged	Clean ports
	Air leak to crankcase	Replace seals or re-seal crankcase to cylinder
	Spark plug partly fouled	Clean or replace

8

		TROUBLESHOOTING
Engine Overheats
	Possible Causes	Remedies
	Cylinder head cooling fins clogged	Clean fins thoroughly
	Restricted carburetor jets	Clean carburetor and jet
	Improper gas to oil mix ratio	Ensure mixture is correct
	Cooling air intake plugged	Remove foreign material and clean
Engine Vibrates Excessively
	Possible Causes	Remedies
	Blade out of balance	Balance blade or replace if damaged
	Bent blade	Replace blade
	Loose engine mounting screws	Tighten engine mounting screws (engine to plate, plate
		to mower housing)
	Bent crankshaft	Replace crankshaft
	Flywheel out of balance (damaged)	Replace flywheel
Engine Crankshaft Will Not Turn
	Possible Causes	Remedies
	Engine brake incorrectly engaged	Disengage brake and inspect and repair as necessary,
		mower only
	Blade jammed in housing	Inspect and repair or replace, mower only
	Piston seized in its cylinder	Inspect and repair or replace
	Starter jammed	Repair starter
Engine Produces Mechanical Knocking Sound
	Possible Causes	Remedies
	Loose blade	Inspect and tighten blade nut to correct torque, mower
		only
	Loose flywheel	Inspect and tighten flywheel nut to correct torque
	Pre-ignition is occurring	See “Engine Pre-Ignites” table
	Loose rod cap	Replace rod and bearings
	Loose engine mounting bolts	Tighten bolts

9

TROUBLESHOOTING

Engine Pre-Ignites

	Possible Causes	Remedies
	Wrong spark plug - too hot	Install the correct type of spark plug
	Low quality fuel (old or stale)	Replace with fresh, unleaded regular fuel
	Carbon buildup in engine	Decarbon engine and muffler
	Excessive alcohol in fuel	Replace with fresh unleaded fuel having no more than
		10% ethanol
	Sheared flywheel key	Inspect and repair

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

	Possible Causes	Remedies
	Slight oil accumulation in crankcase	None; normal on start-up
	Air cleaner element clogged	Clean and re-oil or replace air cleaner element, mower
		only
	Fuel/oil mixture too rich	Drain fuel tank and fill with fuel of correct mixture
	Choke is in “On” position	Move to hi gh speed or “Off” position

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

	Possible Causes	Remedies
	Carburetor running too rich	Clean and check carburetor
	Choke is in “On” position	Move to hi gh speed or “Off” position

10

		TROUBLESHOOTING
Engine Stalls
	Possible Causes	Remedies
	Engine out of fuel	Refill with fresh fuel of the correct mixture
	Engine overloaded	Unload engine and restart
	Fuel filter plugged	Clean fuel filter/tank
	Spark plug fouled	See “Spark Plug Fouled” table
	Fuel cap vent plugged	Replace fuel cap
	Ignition inadvertently grounded	Inspect and repair to remove unwanted ground
	Carburetor vent plugged	Clear vent of obstruction
	Engine overheated	Clear debris from fins or cause of overheating
	Improper lubrication	Tear down and inspect for damage
Spark Plug Fouled
	Possible Causes	Remedies
	Incorrect spark plug	Use correct spark plug
	Carburetor running too rich	Clean/rebuild carburetor
	Clogged air cleaner element	Clean and re-oil element or replace, mower only
	Overuse of “choke” position	Move control off “choke” position and check throttle
		cable adjustment
	Weak ignition system	Replace CD ignition pack
	Worn rings and/or cylinder	Rebuild engine or short block
	Use of poor fuel	Drain fuel tank and replace with fresh, unleaded regular
		fuel having the correct oil mixture
	Fuel/oil mixture too rich	Drain fuel tank and fill with fuel of correct mixture
	Wrong Oil	Use Toro 2-cycle oil, Lawn-Boy DuraForce oil, or
		NMMA TCW3 approved oil

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12

MAINTENANCE

Recommended Maintenance Schedule

	Frequency	Item	Comments
	5 Hours	Fasteners	Check blade and engine mounting fasteners
			frequently. Keep all nuts, bolts, and screws
			tight to ensure safe operation.
	25 Hours	Housing	(Mower only.) Remove the buildup of grass
			clippings and dirt.
			(Self-propelled mower only.) Clean grass
			clippings and debris under drive belt
			mechanism cover and drive belt.
		Spark Plug	Clean, inspect, and regap; replace if
			necessary.
	50 Hours	Air Filter	(Mower only.) Remove and clean each
			mowing season or every 50 hours; more
			frequently if operating conditions are dusty.
		Blade	(Mower only.) Sharpen or replace; maintain
			more frequently if edge is dulled quickly in
			rough or sandy conditions.
		Blade Brake
			Check stopping time every 50 hours or at start
			of each mowing season. Blade must stop
			within 3 seconds of releasing bail. If not,
			repair or replace.
		Lubrication	(Self-propelled mowers only.) Grease rear
			height adjuster brackets.
		Exhaust Ports	Clean every 50 hours or at least once each
			season.
		Fuel System	Check for leakage and/or deterioration of fuel
			hose. Replace if necessary.
	100 Hours	Cooling System	Clean grass clippings, debris, or dirt that clog
			engine air cooling fins; clean more frequently
			under dirty or high chaff conditions.

13