Toro GTS 150 User manual

OHV GTS 150 ENGINE SERVICE MANUAL
Table Of Contents – Page 1 of 4
PREFACE
SAFETY INFORMATION
SAFETY TIPS
SPECIFICATIONS
GTS 150 ENGINE SPECIFICATION
GTS 150 CARBURETOR SPECIFICATIONS
GTS 150 FASTENER TORQUES
TOOL REQUIREMENTS
TROUBLESHOOTING
ENGINE DOES NOT START WHEN "COLD"
ENGINE WILL START "COLD", BUT WILL NOT START "HOT"
ENGINE DOES NOT PRODUCE SPARK
ENGINE HAS LOW COMPRESSION
ENGINE FLOODED WITH FUEL
ENGINE LACKS POWER
BENT PUSH ROD
ENGINE SURGING
ENGINE BACK FIRES
ENGINE AFTER FIRES
ENGINE OVERHEATS
ENGINE VIBRATES EXCESSIVELY
ENGINE CRANKSHAFT WILL NOT TURN
ENGINE PRODUCES MECHANICAL KNOCKING SOUND
PRE-IGNITION
ENGINE SMOKES EXCESSIVELY
ENGINE STALLS
SPARK PLUG FOULED
GTS 150 MAINTENANCE
SERVICING AIR CLEANER
REPLACING THE SPARK PLUG
REMOVING GASOLINE FROM THE FUEL TANK
CHANGING CRANKCASE OIL
CARBURETOR - ADJUSTMENT
COMPRESSION - MEASUREMENT
THROTTLE - ADJUSTMENT
CLEAN THE ENGINE AND RECOIL STARTER
CLEAN THE COOLING SYSTEM
PREPARING THE ENGINE FOR STORAGE

OHV GTS 150 ENGINE SERVICE MANUAL
Table Of Contents – Page 2 of 4
SECTION I CARBURETOR
CARBURETOR DESCRIPTION
CARBURETOR THEORY AND OPERATION
CARBURETOR - REMOVAL
CARBURETOR - PRESSURE TESTING
CARBURETOR - DISASSEMBLY
CARBURETOR - CLEANING AND SERVICE
CARBURETOR - ASSEMBLY
CARBURETOR - ADJUSTMENT
SECTION 2 FUEL SYSTEM
FUEL TANK - OPERATION
FUEL TANK - REMOVAL
FUEL TANK AND FILTER - CLEANING
FUEL CAP - OPERATION
FUEL CAP - SERVICE
FUEL HOSE - REMOVAL
FUEL HOSE - INSTALLATION
SECTION 3 IGNITION
OPERATION
IGNITION OPERATION - FLYWHEEL
IGNITION OPERATION - IGNITION ARMATURE COIL
IGNITION OPERATION - SPARK PLUG
ARMATURE COIL WIRING - OPERATION
AIR GAP - ADJUSTMENT
IGNITION ARMATURE COIL - REMOVAL
IGNITION ARMATURE COIL - TESTING
IGNITION ARMATURE COIL - INSTALLATION
SECTION 4 REWIND STARTER
REWIND STARTER - OPERATION
REWIND STARTER- DISASSEMBLY
REWIND STARTER - ASSEMBLY
REWIND STARTER - INSTALLATION

OHV GTS 150 ENGINE SERVICE MANUAL
Table Of Contents – Page 3 of 4
SECTION 5 ENGINE
ENGINE - OPERATION
INTAKE STROKE
COMPRESSION STROKE
POWER STROKE
EXHAUST STROKE
ENGINE DISASSEMBLY
AIR CLEANER - OPERATION
AIR CLEANER - REMOVAL
REWIND STARTER. OPERATION
REWIND STARTER - REMOVAL
BLOWER SHROUD - REMOVAL
MUFFLER SHROUD - REMOVAL
FLYWHEEL BRAKE - OPERATION (IF INSTALLED)
FLYWHEEL BRAKE - REMOVAL (IF INSTALLED)
FUEL TANK - OPERATION
FUEL TANK - REMOVAL
MUFFLER - OPERATION
MUFFLER - REMOVAL
DIPSTICK AND OIL FILL TUBE - REMOVAL
CARBURETOR - OPERATION
CARBURETOR - REMOVAL
IGNITION COIL - OPERATION
IGNITION COIL - REMOVAL
THROTTLE BRACKET - REMOVAL
ALTERNATOR - OPERATION
ALTERNATOR - REMOVAL (IF INSTALLED)
FLYWHEEL - REMOVAL
ELECTRIC STARTER - OPERATION
ELECTRIC STARTER. REMOVAL (IF INSTALLED)
THROTTLE CONTROL LEVER AND LINK ROD - REMOVAL
VALVE COVER- REMOVAL
HEAD ASSEMBLY - REMOVAL
HEAD - DISASSEMBLY
VALVES AND SEATS - RECONDITIONING
BREATHER - OPERATION
BREATHER - REMOVAL
OIL PUMP - OPERATION
OIL PUMP - REMOVAL
SUMP - REMOVAL
GOVERNOR AND SPLASHER - OPERATION
GOVERNOR AND SPLASHER - REMOVAL
CAMSHAFT - OPERATION
CAMSHAFT- REMOVAL
COMPRESSION RELEASE - OPERATION
COMPRESSION RELEASE - REMOVAL
CRANKSHAFT- REMOVAL
PISTON AND CONNECTING ROD - OPERATION

OHV GTS 150 ENGINE SERVICE MANUAL
Table Of Contents – Page 4 of 4
SECTION 5 ENGINE - continued
PISTON AND CONNECTING ROD - REMOVAL
PISTON RINGS - REMOVAL
PISTON PIN - REMOVAL
GOVERNOR ARM - REMOVAL
ENGINE ASSEMBLY
PISTON PIN - INSTALLATION
PISTON RING - INSTALLATION
PISTON - INSTALLATION
CRANKSHAFT - INSTALLATION
GOVERNOR SHAFT - INSTALLATION
CAM FOLLOWERS - INSTALLATION
CAMSHAFT - INSTALLATION
GOVERNOR/SPLASHER- INSTALLATION
SUMP - INSTALLATION
0IL PUMP - INSTALLATION
BREATHER - INSTALLATION
HEAD - ASSEMBLY
PUSH RODS - INSTALLATION
HEAD - INSTALLATION
VALVE CLEARANCE - ADJUSTMENT
VALVE COVER - INSTALLATION
THROTTLE BRACKET - INSTALLATION
GOVERNOR CONTROL LEVER AND LINK ROD - INSTALLATION
CARBURETOR - INSTALLATION
GOVERNOR - ADJUSTMENT
ELECTRIC STARTER - INSTALLATION
FLYWHEEL - INSTALLATION
ALTERNATOR - INSTALLATION
IGNITION ARMATURE COIL - INSTALLATION
FLYWHEEL BRAKE - INSTALLATION (IF REQUIRED)
MUFFLER - INSTALLATION
MUFFLER SHROUD - INSTALLATION
DIPSTICK TUBE - INSTALLATION
FUEL TANK - INSTALLATION
BLOWER SHROUD - INSTALLATION
REWIND STARTER- INSTALLATION
AIR CLEANER - INSTALLATION
SPARK PLUG - INSTALLATION
ACKNOWLEDGEMENT

PREFACE
This Service and Overhaul Manual was written expressly for the following GTS 150 Overhead Valve Engines:
Model 97777 Type
01 11 -01
Model 97772 Type 01 10-01
Model 97777 Type 31 10-01
MODEL & SERIAL NUMBER
TheToroCompany has made every effort to make this service manual a useful and lasting addition to every service facility.
To assure proper and effective service, and to provide optimum performance for the life of the engine, you are urged to
read this manual carefully.
Itisnot the purposeofthis manualtoteachcomponent theory, but rathertoprovide the mechanic with a working guideline
of maintenance, troubleshooting, test, repair and overhaul procedures.
TheToroCompany reserves the rightto change product specifications or this manual without notice.
The Toro Company gratefully acknowledges the assistance of the Briggs
& Stratton Corporation and Ferris State
Universityinthe productionof this manual.
I COPYRIGHT - ALLRIGHTSRESERVED TheToroCompany
- 1991
Minneapolis, MN 55420 - U.S.A.

TABLE OF CONTENTS
ReferenceInformation
SafetyInformation
.............................................................................................. Page 6
Specifications ............................................................................................................. 7
Troubleshooting., ........................................................................................................ 10
Maintenance
............................................................................................................... 15
ToolRequirements
..................................................................................................... 9
Service Procedures
Section
1 Carburetor
description
..................................................................................................................
operation ....................................................................................................................
removal ......................................................................................................................
pressure testing ..........................................................................................................
disassembly ................................................................................................................
cleaning and service ...................................................................................................
assembly ...................................................................................................................
adjustment ..................................................................................................................
Section2 FuelSystem
fuel tank
operation
...........................................................................................................
removal ............................................................................................................
cleaning ............................................................................................................
fuel cap
operation
...........................................................................................................
service ..............................................................................................................
fuel hose
removal
............................................................................................................
installation ........................................................................................................
Section3 IgnitionSystem
Ignition operation
........................................................................................................
flywheel .............................................................................................................
armature coil .....................................................................................................
19
19
20
21
21
21
22
22
23
23
23
23
23
23
23
25
25
25
Table of Contents
-.
.- ....
...
2
GTS 150

TABLE OF CONTENTS
ServiceProcedures(cont’d)
Section 3 IgnitionSystem(cont’d)
spark plug .......................................................................................................... Page
armature coil wiring
....................................................................................................
air gap adjustment .....................................................................................................
removal ......................................................................................................................
testing ........................................................................................................................
installation ..................................................................................................................
Section 4 RewindStarter
operation ....................................................................................................................
disassembly ...............................................................................................................
assembly ....................................................................................................................
installation ..................................................................................................................
Section 5 Engine
operation ....................................................................................................................
disassembly ...............................................................................................................
air cleaner ........................................................................................................
rewind starter ....................................................................................................
blower shroud ...................................................................................................
muffler shroud ..................................................................................................
flywheel brake ..................................................................................................
fuel tank ...........................................................................................................
muffler ..............................................................................................................
oilfilltube ..........................................................................................................
carburetor .........................................................................................................
ignition coil ........................................................................................................
throttle bracket ..................................................................................................
alternator ..........................................................................................................
flywheel .............................................................................................................
electric starter ...................................................................................................
throttle control lever ...........................................................................................
head components ..............................................................................................
valves and seats reconditioning .......................................................................
breather ............................................................................................................
25
26
26
26
26
26
27
27
28
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29
30
30
30
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31
31
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31
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36
..
GTS 150 3 Table of Contents

TABLE OF CONTENTS
ServiceProcedures(cont’d)
Section 5 Engine(cont’d)
oilpump .................................................................................................... Page 36
sump .................................................................................................................
governor and splasher .......................................................................................
cam shaft and cam followers .............................................................................
compression release .........................................................................................
crankshaft .........................................................................................................
piston and connecting rod .................................................................................
piston rings and pin ...........................................................................................
governor arm .....................................................................................................
assembly
piston pin and rings
...........................................................................................
piston ...............................................................................................................
crankshaft .........................................................................................................
governor shaft ..................................................................................................
cam followers ...................................................................................................
cam shaft ..........................................................................................................
governor and splasher .......................................................................................
sump .................................................................................................................
oil pump ............................................................................................................
breather ............................................................................................................
head ..................................................................................................................
push rods .........................................................................................................
valves ...............................................................................................................
valve clearance adjustment ...............................................................................
throttle bracket ..................................................................................................
governor control lever ........................................................................................
carburetor .........................................................................................................
governor adjustment ..........................................................................................
electric starter ...................................................................................................
flywheel .............................................................................................................
alternator ...........................................................................................................
ignition armature coil .........................................................................................
36
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Table of Contents
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4
GTS 150

TABLE OF CONTENTS
ServiceProcedures (cont'd)
flywheelbrake .......................................................................................... Page45
muffler
.............................................................................................................. 45
dipsticktube ...................................................................................................... 46
fueltank ........................................................................................................... 46
blowershroud ................................................................................................... 46
rewindstarter .................................................................................................... 46
aircleaner ........................................................................................................ 47
sparkplug
......................................................................................................... 47
GTS
150
5 Table of Contents

SAFETY INFORMATION
Thissafetysymbolmeans
WARNING orCAUTION,
TION Read the instruction
because
it has to do wlth safety.
Failuretocomplywiththe
instructionmayresultinpersonalinjury or
death.
PERSONAL
SAFETY INSTRUC-
This manual is intended as a service and repair
manual only. The safety instructions provided in
this manual are for the troubleshooting and service
of the engine only. The individual Operator's
Manual
willcontain safety information on the operation of
the complete product powered by the
GTS 150
engine. Operator's manuals with complete opera-
tional safety instructions are available through:
The ToroCompany
Publications Department
8111 Lyndale Avenue South
Minneapolis,
MN 55430 U.S.A.
SAFETY TIPS
Avoid lacerations and amputations...
Stay clear ofall moving parts whenever the engineis
running. Treat
all normally moving parts as if they
were moving whenever the engineisrunning or has
the potential to start.
Avoid burns...
Do not touch the engine while running or shortly after
running.
Avoid fails....
Do not operate the mower on slippery surfaces or if
footing isquestionable.
Avoid fires and falls...
Wipe up any spilled fuel or oil.
Avoid asphyxiation ....
Never operate an engine ina confined area without
proper ventilation.
Avoid eye injuries ....
Wear eye protection when working with springs or
cables and when running engine.
Avoid unexpected starting of engine ...
Always turn off key and disconnect spark plug wire
before attempting any cleaning, adjustment or repair.
Avoid fires and explosions ...
Use a container designed for gasoline. Avoid spill-
ing gasoline and never smoke while working around
gasoline.
Avoid accidental misuse of fuel. ..
Always store fuel in a properly labeled container
that isdesigned for gasoline.
Avoid injury dueto inferior parts ...
Use onlyTorooriginal partstoinsure that important
safety criteria are met.
Avoid injuryto bystanders ...
Always clear the area of bystanders before starting
or testing
a lawn mower.
Avoid injury dueto projectiles ...
Always clearthearea tobemowedof sticks, rocks
and other debris that could be picked up and thrown
by the mower.
Safety information
6
GTS 150

SPECIFICATIONS
GTS 150 Engine Specification
led, llstrokeoverhead valve
Measurementon page37
I EngineRotation counterclockwise as viewed from PTO
Carburetorfloattypewithfixedmainjet
Fuel unleaded regular
44 ounces (1.3 liters)
solid state magneto type
22 degrees BTDC
primary.2
.4 Ohms, secondary 2400 - 5000 Ohms
Champion RC12YC, gap .030" (.76 mm)
rewind (1 2
volt on some models)
_-
I RecommendedOil detergent SAE1OW-30 or 30, SF,
SG
two stage foam type with optional paper element
manual, snap over design
in tank, washable, 75 micron
Pistonaluminumalloy,permanentmold
I
Piston Rings
two compression,one, 3 piece oil control
GTS 150 7 Specifications

SPECIFICATIONS (cont'd)
GTS 150 Carburetor Specifications
GTS 150 Fastener Torques
Specifications
-
a
GTS 150

TOOL REQUIREMENTS
GTS 150
9
-- _-
Comments
connecting rod, flywheel puller
valve adjusting
nut
valve adjusting jam screw
(Nut driver acceptable)
----_.I
.-
_--__
- I_--^
-.
____~rmY___ -~ .I -
I-p
deep well for spark plug
~._-
_-_s_ ----
B & S part number 19372
B & S part number19069
6 & S part number19334
6 & S part number19070
B & S part number19340
_.____I_____..^_______I- -p_-
I -~
I -___ti-- --
11_1--____---
Specifications

TROUBLESHOOTING
Engine Does Not Start When “Cold”
Engine Will Start “Cold”, but will Not Start “Hot”
inadequatevalve clearance readjustvalves to .005 - .007”(.12 - 17 mm), measured
Engine Does Not Produce Spark
GTS 150

TROUBLESHOOTING (cont'd)
EnginehasLowCompression
incorrect valve clearance readjust valves to .005 - .007"(.15-.17 mm) measured
with engine cold
Engine Flooded with Fuel
carburetor replacefailed parts
--
Engine Lacks Power
GTS 150 11 Troubleshooting

TROUBLESHOOTING (cont’d)
Bent Push Rod
Engine Surging
Engine Back Fires
Engine After Fires
EngineOverheats
Engine Vibrates Excessively
out of balance-blade
.
Trouble shooting
12 GTS 150

TROUBLESHOOTING (cont'd)
Engine Crankshaft Will Not Turn
Engine Produces Mechanical Knocking Sound
Pre-Ignition
. . --_-
with fresh unleaded regular fuel with no more
Engine Smokes Excessively
GTS 150 13 Troubleshooting

TROUBLESHOOTING (cont’d)
Engine Stalls
Spark Plug Fouled

GTS 150 MAINTENANCE
Servicing Air Cleaner
Normally, clean the air cleaner after every
25 operating
hours. More frequent cleaningisrequired when the mower
isoperated industy or dirty conditions.
1. Stop the engine, allow
it to cool and disconnect the
spark plug wire. Remove the key from the key switch
onelectric start models.
2. Rotate the knob securing the air cleaner cover to the
engineuntilthecovercanberemoved.Cleanthe
cover thoroughly. See Figure 1.
Figure 1
3. Ifthe outsideof the foam element is dirty, removeit
from the air cleaner body and cleanitthoroughly. See
Figure
1.
A. Wash the foam elementina solutionof liquid soap
and warm water. Squeeze the element to remove
dirt, but do not twist as the foam may tear. Rinse
thoroughly inclear water.
6. Drytheelementbywrapping it in acleanrag.
Squeeze the rag and
foam element to dry.
C. Saturate the element with
5 teaspoons (25 ml) of
SAE 1 OW 30 engine oil. Squeeze the elementto
remove excessoil and to distribute theoilthor-
oughly.
A damp elementisdesirable.
4. Reinstall the foam element and air cleaner cover. Do
not operate the engine without the air cleaner element
as extreme engine wear and damagewill likely result.
A. Paper elements are available for useinextremely
dirty conditions.Toropart number 77-901
0.
Replacingthe Spark Plug
Use a Champion RC12YC spark plug or equivalent. The
correct air gapis
.030" (.76mm). Remove the plug after
every
25 operating hours and checkitscondition.
1. Stop the engine, allow it to cool and disconnect the
spark plug wire. See Figure
2. Remove the key from
the switch on electric start models.
1. Static Gard
5. Model, Type and
2. Air Cleaner Code Numbers
3. Carburetor
6. Muffler
4. Spark Plug
7. Muffler Guard
2. Clean around the spark plug and use a 518" socket to
remove the plug from the cylinder head. Replace a
cracked, fouled, or dirty spark plug. Do not sand blast,
scrape, or clean electrodes as engine damage could
result from grit entering the cylinder.
3. Set the air gap at .030" (0.76 mm) , See Figure 3. Install
thecorrectlygappedsparkplugandgasketseal.
Tighten the plugto
14 ft Ibs (1 9 N-m)
(.76MM)
1
Figure 3
GTS 150 15
Maintenance