Toro TC 1000 User manual

TC1000 GAS TRIMMER, MODEL 51641
Table of Contents – Page 1 of 3
ABOUT THIS MANUAL
SAFETY INSTRUCTIONS
FOR YOUR SAFETY
MAINTENANCE
MAINTENANCE - AIR CLEANER
MAINTENANCE - MUFFLER
MAINTENANCE - SPARK PLUG
MAINTENANCE - FUEL FILTER
MAINTENANCE - COOLING SYSTEM
MAINTENANCE - TRIMMER IMPLEMENT
MAINTENANCE - FLEX SHAFT
MAINTENANCE - PREPARATION FOR STORAGE
SPECIFICATIONS
ENGINE SPECIFICATIONS
SERVICE SPECIFICATIONS
SPECIFICATIONS
CARBURETOR SPECIFICATIONS
TOOL REQUIREMENTS:
TROUBLESHOOTING
ENGINE DOES NOT PRODUCE SPARK
ENGINE FLOODS DURING STARTING
ENGINE NOT GETTING FUEL
TROUBLESHOOTING
ENGINE LACKS POWER
ENGINE HAS LOW COMPRESSION
ENGINE BACKFIRES (INDICATED BY BURNT AIR CLEANER ELEMENT)
SECTION 1 CARBURETOR
CARBURETOR OPERATION
CARBURETOR OPERATION - THE DIAPHRAGM PUMP
CARBURETOR OPERATION - FUEL METERING & MIXING
CARBURETOR OPERATION - THE PRIMER SYSTEM
CARBURETOR - REMOVAL
CARBURETOR - DISASSEMBLY
CARBURETOR - REASSEMBLY
CARBURETOR - INSTALLATION
CARBURETOR ADJUSTMENT - IDLE SPEED
CARBURETOR ADJUSTMENT - MIXTURE
CARBURETOR ADJUSTMENT - THROTTLE VALVE

TC1000 GAS TRIMMER, MODEL 51641
Table of Contents – Page 2 of 3
SECTION 2 FUEL SYSTEM
FUEL TANK - FUEL TANK - REMOVAL
FUEL TANK - INSTALLATION
PRIMER PUMP - PRIMER PUMP - PROPER USE
PRIMER PUMP - OPERATION
PRIMER PUMP - DISASSEMBLY
PRIMER PUMP INSPECTION
PRIMER PUMP REASSEMBLY
FUEL PICKUP TUBE AND FILTER SERVICE
FUEL CAP - FUEL CAP - OPERATION
FUEL CAP - DISASSEMBLY
FUEL CAP - INSPECTION
FUEL CAP - REASSEMBLY
SECTION 3 IGNITION
IGNITION OPERATION
IGNITION OPERATION - FLYWHEEL
IGNITION OPERATION - IGNITION COIL
IGNITION OPERATION - TRIGGER MODULE
IGNITION OPERATION - SPARK PLUG
AIR GAP ADJUSTMENT
AIR GAP ADJUSTMENT - PREPARATION
AIR GAP ADJUSTMENT - REASSEMBLY
COIL - COIL - REMOVAL
COIL - INSTALLATION
SECTION 4 RECOIL STARTER
RECOIL STARTER - OPERATION
RECOIL STARTER - REMOVAL
RECOIL STARTER - INSTALLATION
RECOIL STARTER - REEL DISASSEMBLY
RECOIL STARTER - REEL REASSEMBLY
RECOIL STARTER - STARTER PULLEY DISASSEMBLY
RECOIL STARTER - STARTER PULLEY REASSEMBLY
SECTION 5 CLUTCH AND FLYWHEEL
CLUTCH SHOES AND FLYWHEEL - OPERATION
CLUTCH SHOES AND FLYWHEEL - INSPECTION
CLUTCH SHOES AND FLYWHEEL - REMOVAL
CLUTCH SHOES AND FLYWHEEL - REASSEMBLY
CLUTCH DRUM AND CLUTCH HOUSING - CLUTCH DRUM AND CLUTCH HOUSING -
CLUTCH DRUM AND CLUTCH HOUSING - REASSEMBLY
SECTION 6 ENGINE
ENGINE - OPERATION
ENGINE - REMOVAL FROM DRIVE TUBE
ENGINE - DISASSEMBLY
ENGINE - CLEANING AFTER DISASSEMBLY

TC1000 GAS TRIMMER, MODEL 51641
Table of Contents – Page 3 of 3
SECTION 6 ENGINE - Continued
ENGINE - INSPECTION
ENGINE - REASSEMBLY
ENGINE - INSTALLATION ON DRIVE TUBE
SECTION 7 CONTROLS
CONTROL AND GRIP - REMOVAL FROM DRIVE TUBE
CONTROL AND GRIP - INSTALLATION ON DRIVE TUBE
SECTION 8 HANDLE
HANDLE - REMOVAL FROM DRIVE TUBE
HANDLE - INSTALLATION ON DRIVE TUBE
HANDLE - ADJUSTMENT
SECTION 9 SHIELD
SHIELD - KNIFE REPLACEMENT
SHIELD - REMOVAL FROM DRIVE TUBE
SHIELD - INSTALLATION ON DRIVE TUBE
SECTION 10 CUTTER HEAD BEARINGS
CUTTER HEAD BEARINGS - REMOVAL
CUTTER HEAD BEARINGS - INSTALLATION
SECTION 11 FLEXIBLE DRIVE SHAFT
FLEXIBLE DRIVE SHAFT - REMOVAL
FLEXIBLE DRIVE SHAFT - SERVICE
FLEXIBLE DRIFT SHAFT - INSTALLATION
SECTION 12 DRIVE TUBE
DRIVE TUBE - REMOVAL
DRIVE TUBE - SERVICE
DRIVE TUBE - INSTALLATION
SECTION 13 TAP AND TRIM HEAD
TAP AND TRIM SPOOL - TAP AND TRIM SPOOL - REMOVAL
TAP AND TRIM SPOOL - LINE REPLACEMENT
TAP AND TRIM SPOOL - REMOVAL
TAP AND TRIM HEAD - TAP AND TRIM HEAD - DISASSEMBLY
TAP AND TRIM HEAD - INSPECTION
TAP AND TRIM HEAD - REASSEMBLY
SECTION 14 FLEX BLADE
FLEX BLADE - REMOVAL FROM DRIVE SHAFT
FLEX BLADE - INSTALLATION ON DRIVE TUBE
SECTION 15 ACCESSORIES
STANDARD AND DELUXE HARNESS - ASSEMBLY

ABOUT THIS MANUAL
This Service Manualwas written expresslyfor the TOR0 TClOOO Gas
PoweredTrimmer. TheTor0 Company hadmade everyeffort tomake the
information in thismanual complete andcorrect.
This manualwas written withthe service technician in mind. It
is organized
so that informationused most oftenis upfront. As a result, you will find
referenceinformation onsafety, maintenance, specifications, special tools
and troubleshootingall inthe front thirdof the manual.
Disassembly, inspection and reassembly proceduresare coveredin thelast
two-thirds of the manual andare grouped bycomponent.
We tried tocover
each common repair with its ownsection or sub-section. For example,you
will findthat air gap adjustment andignition coilreplacement arecalled out
separately.
And, becausecertain componentsare often difficult totroubleshoot without
a good understandingof how theywork, we have included some
component theory. This information can be foundat the beginningof most
service proceduresections.
We are hopeful that you will find thismanual avaluable addition to your
shop. If you shouldcome across anyerrors or
if you have any questions
regarding this manual,pleasecontact us atthe followingaddress:
The Tor0 Company
8111 LyndaleAvenue South
Minneapolis, MN,USA
55420
The Tor0 Company reservesthe right tochange productspecifications or
this manual withoutnotice.
The Tor0 Companygratefully acknowledgesthe assistance of Mitsubishi
Heavy Industries, Ltd. inthe productionof this manual.
COPYRIGHT RIGHTS RESERVED
Tor0 Company 1987
MINNEAPOLIS, MN 55420 U.S.A.

TABLE OF CONTENTS
Reference Information
Page
ForYourSafety 1
Maintenance
2
Specifications 5 I
Tool Requirements 7
Troubleshooting
8
Service Procedures
Page
Section 1
Carburetor
operation 10
disassembly13
reassembly15
installation 17
adjustment 17
removal13
Section
2 FuelSystem
FuelTank
removal19
installation 19
Primer Pump
properuse 19
operation 19
disassembly
20
inspection 20
reassembly 20
Fuel PickupTube and Filter
service
21
Fuel Cap
operation 21
disassembly
22
inspection 22
reassembly 22

Service Procedures (continued)
j
Section 3 Ignition Page
operation 23
air gap adjustment 25
coil removal26
coil installation 26
Section 4
RecoilStarter
Recoil Starter
operation 27
removal 27
installation 27
reeldisassembly27
reelreassembly 28
starter pulley disassembly 29
starter pulley reassembly 29
Section
5 Clutch
Clutch Shoesand Flywheel
operation 30
inspection 30
removal
30
reassembly31
Clutch Drum and Clutch Housing
disassembly31
reassembly31
Section 6
Engine
operation 32
removal from drive tube 34
disassembly35
cleaning after disassembly 36
inspection 37
reassembly38
installation ondrive tube 39
Section 7
Controls
Control andGrip
removal from drive tube 40
installation on drive tube 40
Section 8
Handle
removal from drive tube 41
installation on drive tube 41
adjustment 41
Section 9 Shield
knife replacement 42
removal from drive tube 42
installation ondrive tube 42

Service Procedures (continued)
I
Section 10 Cutter Head Bearings Page
removal
..................................................... 43
installation
.................................................. 43
Section 11
FlexibleDriveShaft
removal ........................................... 44
installation
.................................................. 44
Section 12
DriveTube
removal ..................................................... 45
service
...................................................... 45
installation .................................................. 45
Section 13
Tap and Trim@Head
Tap and Trim@ Spool
removal
................................................. 46
linereplacement
........................................ 46
installation
.............................................. 46
Tap and Trim@ Head
disassembly
............................................. 47
inspection
.............................................. 47
reassembly
............................................. 47
Section 14
FlexBlade
removal from drive shaft 48
installation on drive tube
...................................... 48
Section 15 Accessories
Standard and Deluxe Harness
assembly
.................................................... 49

SAFETY INSTRUCTIONS
PERSONALSAFETY
INSTRUCTION Read
the instructionbecauseit
hasto
do with thesafety.
Failure tocomplywith
the instruction may result
in personalinjury
or death.
This manual is intendedas a service and repair
manual only. Thesafety instructions provided in
this manual are for the troubleshootingand
service of theproductonly. The individual
Operator's Manualwillcontain safety informa-
tion
on the operation of the TC1000.
Operator's Manuals with complete operational
safety instructionsare availablethrough:
The Toro Company
Publications Department
8111 LyndaleAvenueSouth
Minneapolis, MN
55420 U.S.A.
FOR YOUR SAFETY
Avoid possible explosions
Store fuel in acontainer designed for gasoline
andneversmokewhileworking aroundgasoline.
Avoid fires
.. .
Never allow the trimmer enginecloser than one
meter (three feet) to any combustiblematerial.
Avoid accidental misuseof fuel
. ..
Always store fuel inacontainer designed for
gasoline that is properlylabeled.
Avoid falls
.. .
Always wipe upspilled fuel or oil.
Avoid asphyxiation
...
Never operate an engine inaconfined area
without properventilation.
Avoid unexpected starting of the engine
. ..
Always disconnect the spark plug wire before
attempting anycleaning, adjustment orrepair.
Avoid contact witha moving cutterhead.
. .
Always stay clear of the cutter head when the
engine is running. The clutch isamechanical
device whichcouldfail.
Do not rely on it tokeep
the cutter head from turning.
Avoid blindness
...
Always weareye protection when repairing or
running agas trimmer.
Avoid hearing
loss .. .
Wearearprotectionwhen running a gas trimmer.
1

MAINTENANCE
Maintenance Air Cleaner
Servicingoftheair cleaner is recommended
afterevery25 hoursof operation ormoreoftenin
very dusty conditions.
See Fig.
1.
FILTER GRID
AIR
Figure 1
1. Remove the two screws securingtheair
cleaner cover to the trimmer
2. Carefully remove thefiltergrid, foam filter
and filterscreen.
3. Wash thefoam filterin a soap and water
solutionanddrythoroughly.
If thefilter
shows any sign ofdamage, replace it.
4. Saturate the foam filterwith 5 ml(one
teaspoon) of
SAE 30 oil, then squeeze to
distribute theoilevenlyandtoremove excess
oil. Theelementshouldbedamp butnotwet.
5. Wash the filterscreen inacleansolvent and
air dry.
If the filterscreen showsany signs of
damage, replaceit.
6. Reinstall theair cleaner components as
shown inFig.
1. Note thatthe flat side of the
filter grid faces the foam filter.
7. Tighten the aircleaner screws to 0.1 to 0.15
kg m (9 to 13 in Ibs)
2
Maintenance Muffler
Decarbonizing the muffler is recommendedafter
every
50 hours of operation or if engine speed
decreasesdrastically.
1. Remove thethreescrewssecuringthe
muffler cover to the trimmer. See Fig.
2. Be
careful notto
lose the spacer and gasket
material beneath the spark plugprotector
screw.
SPACER
Figure 2
2. Remove the screw securingthemuffler lid
and gasket tothe muffler body.See Fig. 3.
MUFFLER BOD
MUFFLER LID

Maintenance Muffler (cont'd)
3. Rotatethe engine crankshaftuntilthe piston
totally covers the exhaust port.Clean the
exhaustportarea by using a cleanflat piece
of hardwood.Removeall loose particles.
IMPORTANT Use extreme care when clean-
ingthe exhaust port. Stay clearof the piston
so it will not be damaged.
P\
4. Clean any carbonbuildup insidethe muffler
body.
5. Makesurethe muffler gasket is still useable
(replace
if necessary) and install gasket,
muffler body andmuffler lid totrimmer.
6. Reinstallmuffler cover and tighten allfasten-
ers securely. Be sure to install the spacer
underneath the spark plugprotector as
shown in Figure2.
Maintenance Spark Plug
The TC1000 uses an NGK BM6A spark plug or
equivalent. Correctgapis 0.6-0.7 mm (0.024-
0.028"). The recommendedservicing intervalfor
the spark plug is 25 hours of operation.
1. Stop the engine and pull off the spark plug
wire.
2. Cleanaroundthe spark plugand removethe
spark plug from the engineusinga 19mm
(3/4 inch) socket.
IMPORTANT: Replace a cracked, fouled or
dirty spark plug. Do not sand blast, scrape or
cleanelectrodesbecauseenginedamage
could result from grit entering the cylinder.
3.Set the pluggap to 0.6-0.7mm (0.24-0.28").
4. Reinstall the plug and gasket inthe engine.
Tighten to1.2 kg m(104 in Ibs).
Maintenance Fuel Filter
Fuel filterreplacement is recommended after
every 25 hoursof operation.
1. Drain the fuel from the fuel tank intoa
containerdesignedfor gasoline. Start the
engineand letit runat idlespeed until it stops
and all fuel is expended.
r'l
2. Remove the fuel tank cap. Insertaclean wire
with a hooked end intothetank and hookthe
3
pickuptubeabovethefilter. Pullthefilter and
hose out the fuel tank opening.See Fig.4.
Figure 4
3. Remove thefilter by holding theblacktubing
and pullingthe filter straight off.
4. Replacethe filter assembly.
5. Pushthe pickupassembly backintothetank
and install the gas cap.
Maintenance Cooling System
Before eachuse, visually inspect the coolingair
inlet,the coolingfins, and the openings around
the muffler fordebris.Obstructionof these areas
could lead to overheating and possible engine
damage.
IMPORTANT: Becarefulnot to damage the
coolingfins during cleaning.
Maintenance Trimmer Implement
The trimmer implementsrequire no lubrication.
However,cleaning
of theimplementand the
drive shaft area is recommendedafter every 25
hoursof operation. More frequent cleaningmay
berequired
if trimming invery tall grass or if the
implementarea gets excessivelyhot.
Referto either
Tap andTrim Head@, page46, or
Flex Blade, page 48, for information on removal
and cleaning of your particular implement.

Maintenance Flex Shaft
After every 40 hours of operation, the flexible
drive shaft should be removed fromthe drive
shaft housing andall surfaces should beevenly
greasedwithanumber2generalpurposelithium
base grease.
1.Remove the machine screw and nylon lock-
nut that secures the bearing housing to the
drive tube. See Fig.
5.
Figure 5
2. Pullthe bearing housing, shield and trimmer
implement off the drive tube as an assembly.
3. Usinga needle nosed pliers, pullthe flexible
shaft out of the drive tube.
4. Grease the entire length of the shaft with a
lightcoat of #2 general purpose lithium base
grease.
5. Insertthe flexibleshaft intothe nylonsleeve.
Makesurethat theshaftseatsproperlyinthe
clutch drum.Properseatingisobtained
when the flexible shaft is 10 mm
(3/8 inch)
inside the drive tube. See Fig.
6
DRIVE TUBE FLEX SHAFT
Figure 6
4
6. Mountthebearinghousing, shieldand
trimmer implement assembly on the drive
tube. Itmaybenecessaryto turnthetrimmer
implement slightly inorder toget the flexible
shaft to mate properlywiththecutter head
drive shaft.
7. Installthemachine screw that fastens the
bearing housingto thedrive tube andsecure
with a new nylon locknut.
Maintenance Preparation for Storage
Thefollowingprocedure is recommended to
ensure proper operation of the trimmer before
storage of more thana month.
1. Drain the fuel fromthe tank intoa container
designed for gasoline. Start the engine and
letit runatidlespeeduntil itstopsand all fuel
isexpended.
2. Removedirtand grime from external partsof
the trimmer.Ensurethat thecooling finsare
clean.
3. Pullthe spark plug wireoffthe spark plug.
Cleanaround the plug
so that debriswill not
fall intothespark plug holewhen the plug is
removed. Removethe spark plug.
4. Pour 5 ml (oneteaspoon) oftwo-cycleoil into
the spark plughole.This will prevent cor-
rosionfromdamaginginternalengine
components.
5. Pull the recoilstarter handleseveraltimes to
distribute theoil throughoutthe engine.
6. Reinstallthespark plug. Tightenit to1.2kgm
(104 in Ibs). DONOTCONNECTPLUG
WIRE TO THESPARK PLUG.

SPECIFICATIONS
Engine Specifications
Type Air Cooled,2 cycle, gasoline
Bore x Stroke
Oil mixeddirectlywith gasoline
Lubrication Recoil
Starting System
Spark Plug Solid state, transistorized
Ignition System Diaphragm withpiston valve
Carburetor 0.4
I (13.5 02)
Fuel Tank Capacity 32 parts unleaded gasoline to 1 part B.I.A. certified 2 cycle
oil Fuel 3900300 rpm
Clutch EngagementSpeed 3000
300 rpm
Idle Speed Counterclockwise
(as viewed from PTO end)
Engine Rotation
MaximumTorque 0.8
PS @ 7000 rpm (0.55 BHP @ 7000 rpm)
Maximum Output
0.5 PS @ 7000 rpm (0.50 BHP @ 7000 rpm)
Continuous Rated Output 8.0 to 1
Compression Ratio 15.9 cc
(0.97 cu. in.)
Displacement
26
x 30 mm (1.02x1.18 in.)
.________--
0.07 kg m @ 7000 rpm (6.0 in Ibs @ 7000 rpm)
_______.___-
.__-
NGK BM-6A, Champion CY6, or AC CS45
Service Specifications
I Item
Spark Plug Gap
IgnitionCoilAirGap
Crankshaft Runout
Cylinder Diameter
Piston Diameter
Piston to Cylinder
Clearance
Piston Ring
Piston Ring
SideClearance
Standard Dimension
0.6 to 0.7 mm
(0.024 to 0.028")
0.4 to
0.5 mm
(0.016 to 0.020")
0 to 0.05 mm
26.00 to 26.02 mm
(1.0236 to 1.0244")
25.94 to 25.96 mm
0.04 to 0.08 mm
(.00016 to 0.0032")
0.1 to 0.3 mm
(0.004 to 0.012")
0.02 to 0.06 mm
(0.0008 to 0.0024)
(0 to .002")
__-
______-
(1.021 to 1.022")
__-
Allowable Limit
N/A
N/A
0.06 mm (.0025")
Untilplating
exfoliates
See piston to
cylinder clearance
0.05 mm
0.7 mm
0.15 mm
5

Carburetor Specifications
SPECIFICATIONS
Item
Throttle ValveNeedle Jet
High Speed Mixture Screw
Idle Speed Adjusting Screw
Inlet NeedleArm Height
(from bodysurface)
Valve Spring
Valve Opening Pressure
Valve Closing Pressure
Standard
Clip positioned inmiddle groove
3turns out 1/2 turn
Adjust
so idleis 2300 to 2700 rpm
1.4 to 1.6 mm (0.055 to 0.063")
__-
Fastener Torques

TOOL REQUIREMENTS
Flywheel Puller Toro P/N 41-7650 Dial Indicator
SparkTesterToroP/N41-7890 Magnetic
V Blocks &. DialIndicator Stand
Tachometer Toro P/N 42-2730Spark PlugGapping
Tool
FeelerGauge Torque Wrench (14/16)
Compression Gauge Threebond#1104ToroP/N
505-80
Metric Socket Set 3/8" Drive Loctite #242Toro P/N 505-76
Spark Plug Socket Micrometer
#2 Phillips Screwdriver Snap Ring Plier (inside
& outside type)
12
oz. Ball Peen Hammer Hex. KeySet
Needle Nose Pliers
7

TROUBLESHOOTING
Engine DoesNot Produce Spark
control and turn switch around
eplacetriggermodule
Engine Floods During Starting
Possible Causes
Explain proper starting procedureto operator
Operator notDepressing Tickler Valve
Remedy
During Priming
Stale Gasoline Mix fresh fuel
Choke Not Opening Replace damaged
or broken parts
IncorrectGas:Oil Ratio
Tank notVenting Properly
Debrisin Carburetor Repair
or replace gas cap
Usefuel with
32.1 gasoil ratio
Clean carburetor
Engine Not Getting Fuel
Possible Causes
Fuel Tank Empty
Fuel Filter Clogged
Gas Cap not VentingProperly
DiaphragmPump notFunctioning
CrankcaseLeak
Remedy
Fill fuel tank
Replacefuel filter
Replacedefective fuel line
Repair or replacegas cap
Rebuild carburetor
Repair leak
_____-

TROUBLESHOOTING
Engine Lacks Power
Possible Causes Remedy
Grass WoundaroundTrimmer Head Clean trimmer head I
Gas:Oil Ratio ;s,” ;3;h;;;pi I ratio
Stale Fuel
CarburetorImproperlyAdjustedAdjustcarburetor
I
FlywheelKey Shearedor Missing See
“Low Compression”
Low Compression Replaceflywheel key
Engine Has Low Compression
PossibleCausesRemedy
I
Insufficient OilinFuel
Air Leak in LowerCrankcaseReplace lowercrankcase seals
Rebuild engine
Piston RingsExcessivelyWorn Use fuel with gasoil ratio
Air Leak in Cylinder MountingArea
Air Leak at SparkPlug Replace gasketand tighten mounting bolts
Replacedefective plug or cylinder
Engine Backfires (indicatedby burntair cleaner element)
Possible Causes
Muffler and Exhaust Port Plugged
withCarbon
Sheared orMissingFlywheel Key
Operator ConstantlyRevving Engine
I
Decarbonizemufflerand exhaust ports
Replace flywheel key
Educate Operator
__.-
9

SECTION 1
Carburetor Operation
The carburetor forthe TC1000 is a diaphragm
style carburetor. It uses alternating pulses from
the crankcaseto pumpfuel from the fuel tankto
the carburetor.
To adequately describe thefunction of the car-
buretor, it isnecessary to break itsoperation
down intothree systems:
-The Diaphragm Pump
Fuel Metering andMixingSystem
The PrimerSystem
Carburetor Operation The Diaphragm Pump
The diaphragm pumprequires alternating posi-
tiveandnegativeair pressuresworking uponit in
order to fluctuateandperformapumping
function. The sourceof the positiveandnegative
pressures is the lowercrankcase wherethese
pressuresarealternatelybeingcreatedbythe up
and downmovementof the piston.
Transfer ofthesepressure pulses is accom-
plished by apassagewhich leads fromthe lower
crankcase,to a pointjust below the intake port.
See Fig.
7.
PULSE
PASSAGE
Figure 7
Fromthere,the passage leadsthroughtheintake
flange and intothe carburetor. It/terminates in
the diaphragmchamber at apoint called the
pulse hole.See Fig.
8
10
PULSEPASSAGEPULSE HOLE
Figure 8
The pulses vary withthe movementof the piston.
As the pistonmovesupward, vacuum is created
whichpulls the diaphragmtoward the pulse
hole. This movement results in three things
happening on the pumpcover side of the
diaphragm.See Fig.
9.
1. The outletflapper valve is drawn toward the
pumpcover.Thisseals the outlet passageto
ensure that fuel is drawn only through the
fuel inlet.
2. The inletflapper valve ispulled open to allow
fueltoflowfrom thefuel line
into thefuelinlet
cavity.
3. Fuel is drawn intothe fuel pumpcavity.
FUEL PUMP
FUEL INLET
COVER
CAVITY
._I
Figure 9

CarburetorOperation The DiaphragmPump
(cont'd)
As the piston moves downward,another se-
quence occurs which pumps the fuel from the
pumpcavity intothe the maindiaphragm cavity:
See Fig. 10.
OUTLET FLAPPER
INL'ET NEEDLE
Figure 10
1. The exhauststrokesendsapositive pressure
pulseto the pump diaphragm whichpushes
the diaphragm towardthe pumpcover.
2. Thepositivepressure inthe fuel pumpcavity
from being forcedback intothe fuel line.
3. The outletflapper valve is pushedopen.
4. Fuelis forced outof the pump cavity andpast
the inlet needle.
Note: The inletneedle isspring loadedinthe
closed position. The spring pressure isvery
slight andiseasily overcome by the forceof
the fuel coming throughthe passage.
5. The fuel enters the maindiaphragm cavity.
seals theinlet flapper valve to prevent fuel
See Fig. 11.
MAINDIAPHRAGM
CAVITY .ET
NEEDLE
Figure 11
11
Note: The main diaphragmserves only as a
reservoir
so thatfuelcanbeproperly metered
beforeenteringtheventuri. Itdoes not do any
pumpingof fuel during normal operation.
6. Oncethe positive pressureisgone, the
needle valve is re-seated.This allows fuel to
be drawn from the sealed main diaphragm
cavity and into the carburetor throat on the
intake stroke.
Carburetor Operation Fuel Metering & Mixing
Withthe maindiaphragmfilledwith fuel, the
carburetor meters the amount goinginto the
engine by using the high speed mixture screw
and the needlejet.Beforeentering the intake
port ofthe engine, the fuel is mixed with air to
further atomizeitandincreaseits combustibility.
The metering and mixing operation is described
below: See Fig. 12.
SECONDARY
NEEDLE JET
DIAPHRAGMCAVITY
Figure 12
1. Onthe intake stroke, vacuum in the car-
buretor throat drawsfuel from the main
diaphragm cavity. Notethat as the intake
stroke begins, the main diaphragmcavity is
filledwithfuelandthat the diaphragmis
bowed towardthe cover.
2. Thefuel is drawnthroughthe hole inthe top
of the main diaphragm chamber andpastthe
high speed mixture screw. The high speed
mixturescrewregulatesthe
maximum
amount of fuel that canenter the carburetor
throat.
3. Thefuel is thendrawn past thesecondary
needlewhichis attachedtothethrottlevalve.
Itmoveswith the throttlevalve and regulates
the amount of fuel allowed into the car-
buretor throat in proportion withthe throttle
setting.

Carburetor Operation Fuel Metering & Mixing
(cont’d)
4. The venturi is the portion of acarburetor
throat that is narrowed in order to increase
air velocity. On the TC1000 carburetor,the
venturi size is variable and is controlled by
the positionof the throttle valve. See Fig. 13.
THROTTLE VALVE
Figure 13
VENTURI
AIR CORRECTIONJET
properly used, thisprimersystemshouldnot
induce flooding.
The recommended procedurefor priming is as
follows: (See Fig. 15)
5. Thevacuum in the venturi area drawsthefuel
past the secondary needle jet and into the
carburetor throat.
6. To better atomizethe fuel, an aircorrection
jet was added. Theair correction jet allows
filtered air to enter the carburetorthroat
perpendicular to the normal air flow.This
actioncreatesturbulence in theventuri area
and helps mixthefuel with airas itentersthe
carburetor throat. See Fig. 14
Figure 14
7. The air/fuel mixtureenters the engine.
Carburetor Operation The Primer System
The TC100G usesa primersystem that ensures
fuel
is present throughoutthe fuel system. When
CHOKE LEVER
OVERFLOW TUBE
Figure 15
Pushthe tickler button fully inward.
Manually pump the primer pump until a
small amount of fuel is emitted fromthe
overflowtube.
Stop pumping the primer pump and re-
leasethe tickler valve. The engine is now
ready to start.
The operationof the primer systemis
as follows:
See Fig. 16.
DIAPHRAGM
CAVITY
OVERFLOWNEEDLETICKLER BUTTON
__.-
Figure 16