Toro 38180, 38180C, 38181, 38185, 38185C Service Manual

...

2-CYCLE GTS 120 ENGINE SERVICE MANUAL

Table of Contents – Page 1 of 1

PREFACE

I. GENERAL INFORMATION

SAFETY INSTRUCTIONS MAINTENANCE MODEL AND SERIAL NUMBERS TWO-CYCLE ENGINE THEORY AND OPERATION CARBURETOR THEORY AND OPERATION SPECIAL TOOLS LIST

II. MAINTENANCE

AIR CLEANER SPARK PLUG EXHAUST SYSTEM DECARBONING CYLINDER HEAD IGNITION TIMING (MODEL 47PZ2 ONLY) IGNITION TIMING (DIAL INDICATOR) CONTACT POINTS AND CONDENSER MODEL47PZ2 ONLY IGNITION COIL GOVERNOR GOVERNOR OPERATION FUEL TANK CARBURETOR STORAGE

III. TROUBLESHOOTING AND TEST PROCEDURES

PRELIMINARY TROUBLESHOOTING ENGINE BRAKE AND IGNITION SWITCH BBC APPLICATIONS FUEL TANK TESTING COMPRESSION CRANKCASE ENGINE TROUBLESHOOTING CHART

IV. ENGINE REMOVAL, DISASSEMBLY, ASSEMBLY AND REPAIR INSTRUCTIONS

ENGINE REMOVAL ENGINE DISASSEMBLY AND REPAIR RECOIL STARTER REPAIR CARBURETOR REPAIR ENGINE ASSEMBLY AND REPAIR SERVICE DATA SPECIFICATIONS

PREFACE

This service manual was written expressly for TORO Two-Cycle Rotary Mowers.

All

units with the model number

have been taken into consideration.

The Toro Company has made every tool for the service and maintenance of your

assure proper and effective performance, you are urged to read this manual carefully.

The purpose

this manual is to provide the Service Dealer with working

guidelines of maintenance, troubleshooting, test, and overhaul procedures.

The Toro Company reserves the right to change product specifications or this

manual without notice.

47P22,47PD3,47PE4,

effort

to make this service manual a useful

TORO

Rotary Mower Engine. To

and

47PF5

engines

The Toro Company

Service

Department

The

Toro

MINNEAPOLIS,

Company

55420

1986

U.S.A.

TABLE

TOPIC PAGE E

GENERAL INFORMATION

Safety Instructions Maintenance

Model and Serial Numbers Two-cycle Engine Theory and Operation

Carburetor Theory and Operation Engine Specifications

Fastener Torque Specifications Special Tools

II.>

MAINTENANCE

Air Cleaner Spark Plug

Exhaust System Decarboning Cylinder Head Ignition Timing (Model 47PZ2 Only)

Ignition Timing (Dial Indicator)

Contact Points and Condenser (Model 47PZ2 Only)

Ignition Coil (Model 47P22 Only) Ignition Coil (Models 47PD3.47PE4. 47PF5)

Governor Governor Operation

Fuel Tank Carburetor Storage

111

TROUBLESHOOTING AND TEST PROCEDURES

Preliminary Troubleshooting Spark Intensity

Engine Brake and Ignition Switch BBC Applications

Fuel Tank Testing Compression Crankcase

Engine Troubleshooting Chart

ENGINE REMOVAL, DISASSEMBLY, ASSEMBLY AND REPAIR INSTRUCTIONS

Engine Removal Engine Disassembly and Repair

Recoil Starter Repair Carburetor Repair

Service Data Specifications Maintenance Record Maintenance Record

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CONTENTS

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1-1 1-1

1-2 1-2

1-2 1-4

1-5

1-6

11-1

11-2 11-2

11-3

11-4 11-4

11-5

11-6

111-1

111-2 111-2

111-2 111-3 111-4

1v-1

1v-2 1v-4

1v-6

1v-7

SAFETY INSTRUCTIONS

Your rotary mower at the time of its manufacture, meets the blade safety requirements of the Consumer Product Safety Commissions Safety Standard for Walk Behind Power Lawn Mowers.

representative sample was tested and verified by an independent laboratory for compliance with the B71.1-1980 Specifications of the American

National Standards Institute. However, improper

use or maintenance by the operator or owner can still result in injury. To reduce the potential for injury follow these safety instructions.

This machine is equipped with a blade brake which is designed to stop the blade within seconds when the control lever is released. Check to be sure the control and brake function correctly before each use of the mower. Repair

any defective or damaged safety components before operation is commenced. To further reduce the possibility of injury, always stop the E. Wipe up any spilled gasoline. engine before leaving the operator’s position.

This safety symbol means

WARNING PERSONAL SAFETY INSTRUCTION Read the instruction because

with safety. Failure to comply with

the instruction may result in personal injury.

Before Operating

Operate your mower only after reading the engine is running. Stay behind the handle Operators Manual. available by sending the complete model 12. During operation the grass defector and serial number to: The Toro Company, plete bagging assembly must be installed on 81 11 Lyndale Avenue South, Minneapolis, the mower. Minnesota

Never allow children to operate the mower

or adults to operate mower without proper instructions.

3. Become familiar with the controls and know how to stop the engine quickly.

Keep everyone, especially children and pets, away from the area of operation. Remove

sticks, stones, wire and any other debris that might be picked up and thrown by the blade.

TAMPERING WITH SAFETY DEVICE RESULTS IN NONCONFORMANCE WITH

SAFETY STANDARD, MAY RESULT IN PER-

SONAL INJURY. Each time before operating the mower, check for damage or abnormal wear. defective or damaged, repair or replace it before operation is commenced.

55420.

a safety device, shield, or decal

Attn: Publications. 13. Stop the engine and wait for all moving parts

CAUTION

has to

replacement manual is

DEFEATING

COMPONENT WHICH

A A

1-1

6. Wear long pants and substantial shoes. not operate the mower while wearing sandals, tennis shoes, sneakers or shorts. Do not wear loose fitting clothing that could

get caught in moving parts.

long grass will be cut, set the height-of-cut

in the highest position. After mowing, reinspect the area and remove all debris. Then lower the height-of-cut and mow the grass again.

8. Since gasoline is highly flammable, handle it

carefully A. Use an approved gasoline container.

Do not hot or running.

C. Do not smoke while handling gasoline.

Fill the fuel tank outdoors and up to about one-half inch from the top of the tank, not the filler neck.

While Operating

9. Cutting the grass with a rotary mower demands attention. Always maintain secure

footing, balance and control.

10. Cut the grass during the daytime or when there

from side to side, but avoid slopes when the grass is wet. is dry for best results.

11. Keep face, hands and feet away from the mower housing and cutter blade while the

until the engine and all moving parts stop.

to stop before removing the bag, bagging assembly, or unclogging the discharge chute. the high tension wire from the spark plug to prevent the possibility

Use a stick to remove the obstruction.

a solid object is hit by the blade or

14. mower vibrates abnormally, stop the engine

immediately. Disconnect the high tension wire from the spark plug to prevent the possibility of accidental starting. Then check the mower for possible damage, bent blade, an obstruction or loose parts. Repair the mower before using it again.

15. Stop the engine before adjusting the

height-of-cut.

16.

a gravel driveway, road or path must be

crossed, stop the engine

fill

the fuel tank when the engine is

adequate artificial light. Cut slopes

possible, mow when the grass

the chute must be unclogged, pull

accidental starting.

loose sand and

com-

the

rocks are not thrown.

17.

Before leaving the operator’s position behind

the handle, stop the engine and wait for all

moving parts to stop. Do not walk in front of the mower while the engine is running. Disconnect the high tension wire from the spark plug

the mower will be unattended.

18.

not touch any part of the engine while it is running or shortly after it is stopped because the engine will be hot enough to cause a burn.

Muffler

children and pets away.

MAINTENANCE

Before the mower is serviced or adjusted,

19.

stop the engine and remove the key from the switch. Disconnect the high tension wire from the spark plug to prevent the possibility of accidental starting.

20.

To assure the mower is in safe operating condition, keep all nuts, bolts and screws tight. Assure the blade capscrew is tightened to the proper torque.

21.

major repairs are ever needed or tance is desired, contact an Authorized TORO Service Dealer.

22.

the mower must be tipped when it is serviced or adjusted, drain the gasoline from the fuel tank.

23.

a guard, safety device or safety decal is

damaged, replace the defective part(s) be-

fore operating the mower.

24.

To reduce potential fire hazards, assure the mower is free leaves and accumulations of dirt.

25.

The grass bag must always be in good condition; therefore, check it before each use to assure the bag is not torn Always replace a defective grass bag.

26.

Allow the engine to cool before storing the

mower in any enclosure such as a garage or storage shed. any open flame or where gasoline fumes may be ignited by a spark.

27.

Do not overspeed the engine by changing the governor settings. Recommended speed of the engine is and accuracy, have an Authorized TORO Service Dealer check the engine speed with

a tachometer.

28.

At the time of manufacture the mower conformed to the safety standards in effect for

extremely hot. Keep

excessive grease, grass,

deteriorated.

not store the mower near

3000

rpm. To assure safety

assis-

rotary mowers. To assure optimum performance and continued safety certification of the mower, use genuine TORO replacement parts and accessories. Replacement parts

and accessories made by other manufacturers may result in nonconformance with the safety standards.

MODEL AND SERIAL NUMBERS

The TORO Two-cycle Rotary Mower has two sets of identification numbers. There is a model and serial number to identify the engine and a model and serial number to identify the chassis. The engine identification numbers are stamped into the blower housing behind the air cleaner. Model

47PF5 engines built for identification numbers stamped in the blower housing above the spark plug. Engine models 47PE4 and 47PF5 have serial numbers that start with the number zone start application. The number 2 indicates BBC application and the number commercial application.

The chassis identification numbers are located on a decal on the back the rear wheels.

In any correspondence concerning the mower, supply the model and serial numbers to assure that thecorrect information and replacement parts are obtained. Genuine TORO replacement parts may be ordered through your rized Service Dealer.

TWO-CYCLE ENGINE THEORY AND OPERATION

Theory

Two-cycle engines have special advantages which make their use more practical in certain applications. Two-cycle engines are lightweight with an excellent power to weight ratio and can be operated in any position. They are also notably easy to maintain and service because of their uncomplicated design.

The TORO Two-cycle Engine used on the TORO Rotary Mowers is a third-port, loop scavenged design. This design name describes the path of

the fuel bustion chamber, and the exhausting of spent gases.

In a loop-scavenge engine, a high pressure area is created in the crankcase by the downward movement of the piston. Pressurized fuel-air mixture rushes into the combustion chamber through the intake ports and is directed toward

the cylinder head. This fresh mixture then strikes the cylinder head and loops down forcing burnt gases in the combustion chamber out through

air mixture into the crankcase and com-

1, 2 or

1986

3. The

the mower housing, between

have the engine

number 1 indicates

local

indicates

TORO Autho-

1-2

the exhaust ports. The third port design engine has the carburetor mounted on the side of the cylinder. The passage from the carburetor into

the crankcase is called the third port.

All

ports within the engine are opened and closed by the piston skirt as the piston moves up and down within the cylinder.

Operation

The piston closes all engine ports as it moves toward the combustion chamber (Figure 1-1). The moving piston creates a high pressure in the combustion chamber and a partial vacuum in the

crankcase.

Intake Ports Closed

gases begin to be expelled from the combustion chamber (Figure 1-3).

__-

Intake Ports Closed

Exhaust Port

Figure

--l_____m_

Third

Port Closed

1-3

At a point of piston travel slightly before bottom dead center (BBDC)

the

fuel transfer ports, on the

sides of the cylinder walls, are uncovered and

the compressed fuel/air mixture in the crankcase

-is allowed to enter the combustion chamber where they help expel the burnt gases and charge the chamber for the following piston stroke (Figure 1-4).

Figure 1-1

a point slightly before top dead center (BTDC) of the piston travel, from the plug ignitesthe fuel air mixture (Figure 1-2). Also, at this time, the third port opens allowing the fresh fuel/air mixture to rush into the crankcase to equalize the partial vacuum.

Intake Ports Closed

Figure 1-2

When the fuel is ignited by the spark plug, the expanding gases from the burning fuel in the combustion chamber force the piston down thecylinder,

closing the third-port and increasing the pressure

in the

crankcase. At

of the stroke, the exhaust port opens and the burnt

a point approaching the bottom

Intake Ports

Exhaust

Change

Open

__-__

Figure 1-4

CARBURETOR THEORY AND OPERATION Theory

The carburetor receives fuel from the tank and

mixes

with air in the right proportions to

provide a highly combustible mixture to the

engine. As the piston moves up on the compression

stroke a partial vacuum is created within the engine crankcase, causing the greater atmospheric pressure to force air to flow through the

carburetor into the cylinder. The velocity of the air increases as it flows through the carburetor venturi and the air pressure is reduced at this point to less than atmospheric pressure. The differences of pressure in the venturi of the

1-3

carburetor causes atmospheric pressure to push

rawfuel from the

bowl into theair

stream, where

float

it breaks up into a fine spray, or becomes atomized,

and mixes with the air stream (Figure

1-5).

Air passing through the pilot jet from the pilot air fitting draws fuel out of the pilot jet orifice from

the float bowl. This fuel pre-mixes with the

incoming air, then is discharged into the carburetor bore where the fuel becomes atomized

Float

Bowl

(Figure

To Engine

1-7).

Figure

1-5

Operation

When starting the engine, an extra rich mixture is required. The choke plate is closed by the opera-

tor to provide an approximate

8:1

ratio of fuel to air for this rich mixture. Closing the choke plate further reduces the air pressure area in the venturi to increase the fuel drawn into the car-

buretor bore. In this condition fuel is drawn from the float bowl through the pilot system ports as well as the main discharge tube to achieve the proper starting mixture (Figure

Pilot System

1-6).

Pilot

Jet

Pilot Air Fitting

LOAD

Figure

the throttle plate is opened to compensate for

1-7

loads the engine is being placed under, the main

discharge tube becomes the main source of fuel.

Opening the throttle plate increases the flow of

air through the venturi and strengthens the low

pressure area at the main discharge tube. Fuel discharge increases at the main discharge tube as

decreases from the pilot system. Air

drawn from the air correction jet through holes along the length of the main discharge tube. This pre-mixes air with the fuel before it enters the carburetor bore for more efficient atomizing of

:he fuel (Figure

1-8).

COLD START

Figure

1-6

Fuel atomization becomes more efficient, due to heat, once the engine has reached normal operating temperature.

a result, the engine

does not require the rich mixture it did for starting and the choke plate must be moved

the open position. The engine speed is now regulated by the throttle plate. In no load condi-

tions a small portion of the fuel may be drawn from the main discharge tube, however the pri-

mary fuel supply is drawn from the pilot circuit.

1-4

Float

Bowl

/pilot

System

Figure

UNDER LOAD

1-8

ENGINE SPECIFICATIONS

Model

~---

47P22

Type 2 cycle, single cylinder piston

ported, air cooled Rotation (viewed from output end) Counter-clockwise Displacement 121 cc (7.38 cu. in) Bore 58 mm (2.28 in)

Stroke 46 mm (1.81 in) Crankshaft 24.9 mm (.98in) forged steel

Rated Output

Torque .73 kg-m (5.28 ft-lb)

3.5

Hp @ 3600 RPM

3000

Compression Ratio 6: 1 Compression

Gas-Oil Ratio

8.4kps/cm2 20 psi) to

10.5 kps/cm (1

50:

psi)

Gasoline Unleaded Regular

TTO

Oil 2 cycle oil

Fuel Tank Capacity Air Cleaner Carburetor Mikuni

High Altitude Jet Governor Mechanical Flyweight

1.89

(2 qt)

Two stage foam element

BV-15std.

main jet #80

#77.5

RPM

47PD3

#76.3 #72.5

Spark Arrester Muffler Optional (PN 81-0200) Starter Recoil only

Spark Plug NGK-BPMR6A

NGKBPMR4A

Ignition Timing 22" 2" BTDC Ignition Timing, Piston Position 1.76-2.51mm (.069-.099in) BTDC Contact Point Gap .35 mm (.014in)

N/A

Ignition Coil Air Gap .38-.50 mm (.015-.020in) Float Height Setting (Black Float)

*The black float may be used on these engines as a replacement. Part number

N/A

11/16"

81-0970.

N/A

FASTENER TORQUE SPECIFICATIONS

Adapter Plate Housing Capscrews (3/8-16UNC) 2.9-4.6 Kg-m (21

-33

ft-lb) Blade Capscrew 6.2-8.3 Kg-m (45-60 ft-lb) Flywheel Nut (M 10) 4.0-5.0 Kg-m (29-36 ft-lb) Muffler Nuts (M 8)

Air Cleaner Lock Nuts (M 6)

Adapter Plate Engine Capscrews (M 8)

90-120Kg-Cm (100-140 in-lb) 60-90 Kg-Cm (70-1

in-lb)

90-120Kg-Cm (100-140in-lb)

Crankcase Capscrews (M 6) 80-95 Kg-Cm (70-1 10 in-lb)

Shroud Ignition Switch Mounting Capscrew (M 6) 80-1 15 Kg-Cm (90-1

Air Cleaner Mounting Capscrew (M

Muffler Capscrews (M 6)

-..-

40-70 Kg-Cm (45-80 in-lb)

in-lb)

17-26 Kg-Cm (20-30 in-lb) Recoil Starter Cup Capscrews (M 6) 80-95 Kg-Cm (70-1 10 in-lb) Recoil Mounting Capscrews (M 6) 35-65 Kg-Cm (40-75 in-lb)

Recoil Center Capscrew (use thread lock compound) 80-95 Kg-Cm (70-1 10 in-lb)

Spark Plug (M 14) 70-1

__-

Kg-Cm (80-1 20 in-lb)

Throttle Plate Capscrews (M 6) 80-95 Kg-Cm (70-1 10 in-lb)

1-5

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