Toro 51603 Operating instructions

GAS TRIMMER GUIDE, MODELS 51630, 51603, 51604
Table of Contents – Page 1 of 1
FOREWORD
GENERAL INFORMATION
MAINTENANCE PROCEDURES
AIR CLEANER MAINTENANCE
EXHAUST SYSTEM MAINTENANCE
FLEXIBLE DRIVE SHAFT MAINTENANCE
CARBURETOR ADJUSTMENTS -- MODEL TC-1 500 WITH TILLOTSON
CARBURETOR ADJUSTMENT -- MODELS TC-300, TC-400 WITH WALBRO
TROUBLESHOOTING AND TEST PROCEDURES
DISASSEMBLY, REPAIR, REASSEMBLY INSTRUCTIONS
WALBRO CARBURETOR OPERATION
CUTTER HEAD TROUBLESHOOTING
CLUTCH REPAIR

GASOLINE POWERED TRIMMER
MAINTENANCE
& REPAIRGUIDE
MODEL NO. 51630 1000001 & UP
2000001 & UP
2000001 & UP
COPYRIGHT(C) ALL RIGHTS RESERVED
The Tor0 Company - 1982
MINNEAPOLIS, MN 55420 U.S.A.
Form 492-0266

FOREWORD'
This Maintenance and Repair Guide will provide you with complete information necessaryto
accomplish the maintenanceand repair of gasoline-powered flexible line trimmers powered by
the new line of the lightweight two-cycle engines manufacturedby The Tor0Company
The number of repair procedures for this lineof engine;s has been limited for simplicity and
economyTherepairsare easy to accomplish.evenforoperators or mechanicswho have
limitedexperience in the repairof small two-cycle engines
Should you require additional information concerning these trimmers. we urge you to write to
us Addressinquiriesto:
The Tor0 Company
8111 Lyndale Avenue South
Minneapolis MN 55420
Attn..Service Department
TABLE OF CONTENTS
PAGE
Two-cycle Engine -Theory of Operation 1
Engine operation
1
EngineSpecifications 3
Engine Torque Specifications 3
Air CleanerMaintenance 4
GeneralInformation 1-3
Maintenance Procedures ...................................... 4-7
ExhaustsystemMaintenance 4
FlexibleDriveShaftMaintenance 5
Carburetor Adjustments; Model TC-1500 (Tillotson Carburetor) 5-6
Carburetor Adjustments; Models TC-300 & TC-400 (Walbro carburetor) 6-7
TestingCylinderCompression 7
CheckingFuel Tank venting 8
EngineTroubleshootingChart 9
Troubleshooting andTest Procedures 7-9
Preliminary Checks: 7
CompressionTest Procedure 7
CheckingFor Spark 8
CheckingFuelTank 8
CheckingtheStopSwitch 8
Disassembly.Repair. Reassembly Instructions 10-18
Trimmer EngineRemoval. Disassembly. Replacement 10
Starter Rope Replacement 12
Starter Assembly Replacement ......................................
Walbro Carburetor Servicing 14
Cutter HeadTroubleshooting Chart 16
WalbroCarburetorOperation 13
Clutch Repair 17
Automatic Line FeedRepair 18

GENERAL INFORMATION
Two-cycle Engine Theory of Operation
Two-cycleenginesareusedon TORO Trimmers
becauseof their:
1. Light weight.
2. Excellent power-to-weight ratio
3. Ability tooperate in any position
4.Easy maintenance
5. Simpleconstruction
The TORO Two-cycle Engineused onthe TC-1500,
TC-300 and TC-400 Trimmers is a third-port, loop-
scavenged design. This design name describes the
path of the fuel/air mixture into the crankcase and
combustion chamber, andtheexhausting of spent
gases (Fig. 1
st Port
\
transfer
(Both
Cylinder)
Figure 1
In aloop-scavengedengine with a third-port, the
flow of thefuel/airmixturecanbedescribed as
follows: (SeeFig. 1).
1. The fresh fuel/air mixture enters the crankcase
through the third-port on the side of the cylinder.
The oil in thefuel/airmixturelubricatesthe
moving parts within the crankcase.
2. The fuel/airmixtureistransportedthroughthe
fueltransferportstothecombustion chamber
where it iscompressed, ignited, andthen expelled
from the engine through the exhaustport.
Engine Operation ,
The piston closes all engine portsas it movestoward
the combustion chamber(Fig. 2). The moving piston
creates high pressure in the combustion chamber
and partial vacuum in the crankcase.
Figure 2
Compression Stroke
At a point slightly before topdead center(BTDC) of
the pistontravel, the spark from the plug ignites the
fuel air mixture(Fig. 3). Also, at this time, the third-
port opens allowingthefreshfuel/airmixtureto
rushintothecrankcasetoequalizethepartial
vacuum.
Spark Ignites
Fuel/Air Mixture
I
Piston at or
Near
T.D C.
Exhaust Port
Closed
Open
FreshFuel/AirMixture
Lubricates
Moving Parts
Figure 3
Ignition
1

GENERAL INFORMATION
Thee expandingbanding gases fromtheburningfuel in the
combustionchamberforcethepiston downthe
cylinder,closing thethird-port andincreasingthe
pressure in thecrankcase.Atapointapproaching
the bottomof the stroke, the exhaust portopens and
the burntgases begin to be expelled from thecom-
bustion chamber(Fig. 4).
Mixture Compressed
Closed
Figure 4
Power/Exhaust
At a point of piston travel slightly before bottomdead
center (BBDC) the fuel transferports, on thesides c
the cylinderwalls,areuncoveredandthe com-
pressedfuel/air mixture in thecrankcase is allowed
to enter the combustion chamber where they help
expel the burnt gases and charge the chamber fa
the following pistonstroke (Fig. 5).
Figure 5
Exhaust/Fuel transfer

ENGINE SPECIFICATIONS
TC TC300
TC400
(Model51630)(Model51603) (model51604)
32:1
or unleadedregularleaded
Genuine TOR0 Two-CycleOilor otherhighquality two-cycle oil,BIA
approved
.40 (13.5 oz.)
Fillotson ModelSP-1A WalbroWa-120serieswith
with selfcontained fuel self containedfuel
pump,acceleratorpumpand filter screen
pumpand filter screen
Factoryadjustedand Factory adjusted and testrun.
Procedures-pp. testrun. Adjusting Procedures
Solid state,-capacitive discharge ignition(CD1)
1.29-1.67mm(-051-066in.)BTDC
22degreesBTDC
.20-.30mm (.008-.012 in.)
ENGINE TORQUE SPECIFICATIONS
t
CooIing~Shroud Screws
Carburetor Mounting Screws
NOTE: MetricTorque Conversions:
inch-pounds X1.152= kilogram-centimeters
foot-pounds X .1383 = kilogram-meters
TORQUE-Kg-cm/Kg-m
~.TORQUE-in.-lbs/ft-lbs
.35-41Kg-cm 30-45in.-lbs.
23-35Kg-cm 20-30in-lbs
29-40Kg-cm-15-35 in.-lbs.
12-23Kg-cm10-20in-lbs
29-40Kg-cm
23-35kg-cm 25-35in.-lbs.
3

MAINTENANCE PROCEDURES
AIR CLEANER MAINTENANCE
Check and clean the foamair cleaner element every
eight operating hours, and the felt air cleaner once a
season.
1. Remove the air cleaner cover by pressing up on
thebottom of the cover to releasethelower
mounting tab and pressing in on front of thecover
to release the upper tab. DO NOT FORCE.
2. Carefully remove the filter clip or filter retainer.
Remove the foam filter and felt filter (Figures 6
and 7).
Air Cleaner Housing
Press Here to Remove
Figure 6
Air CleanerHousing
Felt Filter
3. Wash the foam filter in asoap and water solution
and dry thoroughly. If the filter shows any signof
damage or deterioration, replace it.
4. Saturate the foam filter with one teaspoon(5ml)
SAE 30 oil. Squeeze the filter to distribute the oil
evenly andtoremoveexcess oil. A damp element
is necessary to ensure proper functioning of the
air cleaner.
5. Inspect the felt filter.If it isdirty, wash it in clean
solvent and air dry it. If the filter showsany sign
of ,damage it must be replaced.
6. Reinstall the felt filter, foam filter, and filter clipor
retainer in the air cleaner housing (Figures 6 and
IMPORTANT:Make sure thepeg in theair cleaner
housingfitsthroughthesmallhole in the felt
filter. Both filters must cover the opening in the
air, cleaner housing.
7. Reinstallthe aircleaner cover bypressingthe
cover in, and up, behind the choke lever and then
pressthe lower mounting tab into the hole in the
engine housing. DO NOT FORCE.
7).'
EXHAUST SYSTEM MAINTENANCE
NOTE: Some states require that aspark arrester be
attached to the muffler if the trimmer is tobe used in
forested areas, or on other public lands. Be sure to
check your local state laws before using your gaso-
line powered trimmer.
An important part of the maintenance procedure for
all two-cycle engines is the cleaningor decarboning
of the exhaustsystem.This is done to assure the
unobstructedflow of exhaust gases andparticles
from the combustion chamber. A severely carboned
muffler, spark arrester screen. and/or exhaust port
will cause poorstarting and low power outputof the
trimm'er engine.
1. Remove the muffler shield, screen, mufflerand
2. Soak the screen in solvent and remove the carbon
build-up with a wire brush,or replace thescreen.
3. Clean the muffler baffle holes inside the muffler
exhaust gasket.
with a screwdriver.
4. Check thecylinderexhaust port.If necessary,
remove the carbon deposits from the port using a
wiiden stick (Fig. 8).
Figure 8
4

IMPORTANT:WHENREMOVINGCARBONDE-
POSITS,CLOSETHEPORT WITH THEPISTON
TOPREVENT LOOSE CARBON DEPOSITS FROM
FALLING INTO THE CYLINDER. TAKE CARE NOT
TOSCRATCHTHEPISTON. DONOTUSE A
METALTOOL SUCHAS A SCREWDRIVER.
5. Reassemble the mufflercomponents. Useafresh
exhaust gasket.
FLEXIBLE DRIVE SHAFT MAINTENANCE
The flexibledriveshafthasbeenlubricatedatthe
factory. After approximately every 40 hours of opera-
tion, the shaft should be removed from its housing
and its entire surface coated with a No.2 general
,purpose, lithium-base grease. To remove the shaft,
loosenthelowerhandleand slide it towardthe
engine assembly to expose the clamp. Loosen the
clampand separate the upper andlowertube as-
semblies. The shaft will then be able to be pulled
from the lower tube(Fig. 9).
Figure9
CARBURETOR ADJUSTMENTS MODEL
TC-1500WITH TILLOTSON CARBURETOR
The carburetor has been adjusted at thefactory, but
an adjustment may be required to compensate for
differences in fuel,temperatureandaltitude. The
TillotsoncarburetorusedontheTC-1500isnot
serviceable. Ifcarburetiondifficultiescannot be
corrected by adjustment, thecarburetormustbe
replaced.
IMPORTANT:The correct amountof line must be fed
fromthetrimmer spoolbeforeadjustingthecar-
buretor to ensure thattheengineisadjustedfor
operationwhile under load..
1.Remove aircleaner coverby pressingup on
bottom ofcover to release lowermountingtab
and pressing in on frontof covertorelease upper
tab. DO NOT FORCE (Fig. 10).
Figure 10
CAUTION: THEENGINEMUST BE
RUNNING SO FINAL ADJUSTMENTS OFTHE
CARBURETORCANBEPERFORMED.
AL INJURY,KEEPHANDS, FEET AND
FACEAWAY FROM MOVING PARTS.
TOGUARD AGAINST POSSIBLEPERSON-
2.Start the engine and let it warm up for approxi-
mately 3-5 minutes. Do not adjust the carburetor
when theengine is cold. Be sure to perform the
carburetor adjustments while in an area that is
wh
AN I
NO
poi
Hig
tothe average outdoortemperatureat
the trimmer will be used.
CAUTION; DONOTRUN THE TRIMMER
ORS WITHOUT ADEQUATEVENTILA-
EXHAUST FUMES ARE POISONOUS
COULDBE DEADLY IF INHALED.
If the engine will not start or if the refer-
setting islost, set both screws so the arrows
to "5%". Lownumbersettingsare lean.
number settings are rich.(Fig. 11).
Figure 11
5

MAINTENANCE PROCEDURES
3. AdjustIdleFirst: With engineidling,rotatethe
Low Speed Screw (L)for the leanest fuel mixture
that allows stable idle, and acceleration without
hesitation.
4. If necessary, idle speed canbeincreasedby
turning the idlestop screw clockwise(Fig. 12).
2. Low Speed Screw (L) (Fig. 13) Close the screw
by gently rotating it clockwise untilalight seating
resistance is felt. Next, rotate the screw 11/4-11/2
turns counterclockwise.
3. Idle Screw(Fig. 13) Close the screw by rotating
it clockwise until the screw contacts the throttle
leverAftercontactis made, continueturning
screw 11/2-21/2 additional turns.
Figure 12
5. Holdthethrottletriggeratthemaximum speed
position and adjust the HighSpeed Screw (H) for
maximum enginespeed.
6. Recheck the idle adjustment.
CARBURETORADJUSTMENTMODELS TC-
300, TC-400 WITH WALBRO CARBURETOR
IMPORTANT: Do not close the carburetor adjusting
screws too tightlyas damageto thescrews andseats
may result. Also, the correct amountof line mustbe
fedfromthetrimmer spoolbeforeadjustingthe
carburetor to ensure that the engine is adjusted for
operation while under load.
1. HighSpeed Screw(H) (Fig. 13) Closethe screw
by gently rotating it clockwise untila light seating
resistance is felt.Next, rotate the screwone turn
counterclockwise.
Figure 13
NOTE: Although these settingsare approximate,
the should be able to be started. Further
adjustments of the carburetor may be necessary
toobtainthe bestperformanceforyour area.
Steps 4-6 shouldbefollowed tofinetunethe
carburetor. Whenmakingtheseadjustments,
turn the screws 1/8 of aturn atatime and wait for
the 'engine to respondto thechange.
6

MAINTENANCE PROCEDURES
4. Start the engine and let it warm up for approxi-
mately 3-5 minutes. Do not adjust the carburetor
when the engineis cold. The adjustments should
be made at thetemperatures that thetrimmer
will beused. Allow the engine toidle. If neces-
sary, re-adjust the idlespeed to keep the engine
fromstalling (3000-3500 RPM onthe TC400,
3000-4500on theTC300)
CAUTION: DONOTRUNTHE TRIMMER
INDOORS WITHOUT ADEQUATE VENTILA-
TION.EXHAUST FUMES ARE POISONOUS
AND COULD BE DEADLY IF INHALED.
5. With' theengine idling, slowly turn the lowspeed
screw clockwise and note the position at which
theenginebeginstoslowdown.Nowturn the
screw counterclockwise and again note the posi-
tion when the engine speed is reduced. Set the
screw at a pointmidwaybetweenthese two
positions.
6. Hold the throttle wideopen and follow the same
procedure toset the highspeed screw.
7. Re-checkthe idle adjustment.
8. Install the air cleanercover.
TROUBLESHOOTING AND
TESTPROCEDURES
Generally, allgasoline-poweredproductsrequire
some form of service or repair during their lifetime.
The amount of time andexpense involved in repair-
ing a product canbe greatly impactedby the amount
of timerequiredtoinitiallydeterminethe cause of
the difficulty. Therefore, it is recommended tomake
these preliminary checks before proceeding to sec-
ondary troubleshootingprocedures.
Preliminary Checks
1. Check for ignition:
a. Check the start/stop switch position
2. Check the spark plug:(refertospecifications.
Page 3)
a. To ensure the correcttype
b. For damage to the insulator
c. For excessive carbon or burnt electrodes
d. For the correctgap
e. Check for spark (refer to page 8)
3. Check the fuel supply:
a. Check the choke position
b. Check the conditionof the fuel, for freshness,
cleanliness, and proper mixture
4. Check the air cleaner: (refer topage 4)
a.For loose or damaged mounting screws
b.For dirtyfilterelements
c. For excessiveoil in the foam element
5. Check cylindercompression(referto page 7)
Testing Cylinder Compression
A compression test of the engine can provide vital
information on the general conditionof the working
parts within the engine. Thistest will indicate a worn
cylinder,piston, or ringandgenerallydetermine
whether theengineissound or if it should be
replaced,.
Compression Test Procedure
1. Install the compressiongauge into the sparkplug
hole.:IMPORTANT: Becertain that nomorethan a
1/2” of the gauge is threaded into the cylinderas
damage to the pistonmay result (Fig. 14).
Figure 14
Compressiontesting
2. Pull the starterropeseveral times to obtain the
highest possible compression reading.
3. If the compression reading is below 100 psi (689
kPa), cylinder, piston, or ring damage should be
suspected If so damaged, a new engine short-
block /shouldbe installed.
7