How it Works
Toro
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51643
Service Manual
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Parts Catalogue
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Toro 51643, 51644, 51645 Service Manual

TC3, 4, 5000 GAS TRIMMER, MODELS 51643, 51644, 51645
Table of Contents – Page 1 of 4
ABOUT THIS MANUAL
SAFETY INFORMATION
FOR YOUR SAFETY...
SPECIFICATION
TOOL REQUIREMENTS:
TROUBLESHOOTING
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
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
TC3, 4, 5000 GAS TRIMMER, MODELS 51643, 51644, 51645
Table of Contents – Page 2 of 4
SECTION 2 FUEL SYSTEM - Continued 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 TC3000/TC4000 AIR GAP ADJUSTMENT - PREPARATION TC3000/TC4000 AIR GAP ADJUSTMENT TC3000/TC4000 AIR GAP ADJUSTMENT - REASSEMBLY TC5000 AIR GAP ADJUSTMENT - PREPARATION TC5000 AIR GAP ADJUSTM ENT TC5000 AIR GAP ADJUSTMENT - REASSEMBLY COIL - COIL - REMOVAL COIL - INSTALLATION
SECTION 4 RECOIL STARTER RECOIL STARTER - OPERATION RECOIL MECHANISM - REMOVAL RECOIL MECHANISM - DISASSEMBLY RECOIL MECHANISM - REASSEMBLY RECOIL MECHANISM - INSTALLATION STARTER PULLEY - REMOVAL STARTER PULLEY - INSTALLATION
SECTION 5 CLUTCH SHOES AND FLYWHEEL CLUTCH SHOES AND FLYWHEEL - OPERATION CLUTCH SHOES AND FLYWHEEL - DISASSEMBLY 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 ISOLATION MOUNT (TC4000 AND TC5000 ONLY) - ISOLATION MOUNT - ISOLATION MOUNT - DISASSEMBLY ISOLATION MOUNT - REASSEMBLY
SECTION 6 ENGINE ENGINE - OPERATION ENGINE - REMOVAL FROM DRIVE TUBE
TC3, 4, 5000 GAS TRIMMER, MODELS 51643, 51644, 51645
Table of Contents – Page 3 of 4
SECTION 6 ENGINE - Continued ENGINE - DISASSEMBLY ENGINE - CLEANING AFTER DISASSEMBLY ENGINE - INSPECTION ENGINE - REASSEMBLY ENGINE - INSTALLATION ON DRIVE TUBE
SECTION 7 CONTROLS
CONTROL - DISASSEMBLY CONTROL - REASSEMBLY GRIP - REMOVAL GRIP - INSTALLATION
SECTION 8 HANDLE TC3000 HANDLE - REMOVAL FROM DRIVE TUBE TC3000 HANDLE - INSTALLATION ON DRIVE TUBE TC3000 HANDLE - ADJUSTMENT TC4000 HANDLE - REMOVAL FROM TUBE TC4000 HANDLE - INSTALLATION ON DRIVE TUBE TC4000 HANDLE - ADJUSTMENT TC5000 HANDLE - REMOVAL FROM DRIVE TUBE. TC5000 HANDLE - INSTALLATION ON DRIVE TUBE TC5000 HANDLE - ADJUSTMENT
SECTION 9 SHIELD
SHIELD - REMOVAL FROM DRIVE TUBE SHIELD - INSTALLATION ON DRIVE TUBE SHIELD - MOUNTING CUTTER KNIFE ON SHIELD
SECTION 10 GEARBOX
GEARBOX - REMOVAL GEARBOX - INSTALLATION ON DRIVE TUBE GEARBOX - SEAL REMOVAL GEARBOX - SEAL INSTALLATION
SECTION 11 DRIVE SHAFT AND TUBE
DRIVE SHAFT - DRIVE SHAFT - REMOVAL DRIVE SHAFT - INSTALLATION DRIVE TUBE - DRIVE TUBE - REMOVAL DRIVE TUBE - INSTALLATION
SECTION 12 LEECO MANUAL FEED HEAD
LEECO MANUAL FEED HEAD - SPOOL REMOVAL LEECO MANUAL FEED HEAD - LINE REPLACEMENT LEECO MANUAL FEED HEAD - SPOOL INSTALLATION
TC3, 4, 5000 GAS TRIMMER, MODELS 51643, 51644, 51645
Table of Contents – Page 4 of 4
SECTION 12 LEECO MANUAL FEED HEAD - Continued LEECO MANUAL FEED HEAD - DISASSEMBLY LEECO MANUAL FEED HEAD - INSPECTION LEECO MANUAL FEED HEAD - REASSEMBLY
SECTION 13 KAAZ MANUAL FEED HEAD
KAAZ MANUAL FEED HEAD - DISASSEMBLY KAAZ MANUAL FEED HEAD - LINE REPLACEMENT KAAZ MANUAL FEED HEAD - REASSEMBLY
SECTION 14 PLASTIC FIXED LINE HEAD
PLASTIC FIXED LINE HEAD - LINE REPLACEMENT PLASTIC FIXED LINE HEAD - REMOVAL
SECTION 15 METAL FIXED LINE HEAD
METAL FIXED LINE HEAD - LINE REPLACEMENT METAL FIXED LINE HEAD - REMOVAL METAL FIXED LINE HEAD - INSTALLATION
SECTION 16 TAP AND TRIM HEAD
TAP AND TRIM LINE REPLACEMENT - TAP AND TRIM SPOOL - TAP AND TRIM SPOOL - LINE REPLACEMENT TAP AND TRIM SPOOL - INSTALLATION TAP AND TRIM HEAD - DISASSEMBLY TAP AND TRIM HEAD - INSPECTION TAP AND TRIM HEAD - REASSEMBLY
SECTION 17 METAL BLADES
METAL BLADE - REMOVAL METAL BLADE - INSTALLATION
SECTION 18 HARNESSES STANDARD AND DELUXE HARNESS - ASSEMBLY
SECTION 19 SPARK ARREST O R MUFFL ER
SPARK ARRESTOR MUFFLER - REMOVAL SPARK ARRESTOR MUFFLER - INSTALLATION SPARK ARRESTOR MUFFLER - MAINTENANCE
ABOUT
This Service Manual was written expressly for the Tor0 TC3000, TC4000 and TC5000 Gas Powered Trimmers. The Tor0 Company had made every effort to
make the information
in
this manual complete and correct.
THIS
MANUAL
This manual was written with the service technician that information used most often is
information on safety, maintenance, specifications, special tools and
troubleshooting all
Disassembly, inspection and reassembly procedures are covered two-thirds of the manual and are grouped by component. We tried to cover each common repair with its own section or sub-section. For example, you will find that air gap adjustment and ignition coil replacement are called out separately.
And, because certain components are often difficult to troubleshoot without a
good
understanding of how they work, we have included some component theory. This information can be found of the beginning of most service procedure sections.
We are hopeful that you will find this manual a valuable addition to your shop. If you should come across any errors or if you have any questions regarding this manual, please contact us at the following address:
in
the front third of
81
11
Bloomington, MN, USA 55420
up
front. As a result, you will find reference
the
manual.
The Tor0 Company
Lyndale Avenue South
in
mind.
It
is organized
in
so
the last
The Tor0 Company reserves the right to change product specifications or this manual without notice.
The Tor0 Company gratefully acknowledges the assistance of Mitsubishi Heavy Industries, Ltd.
in
the production of this manual.
COPYRIGHT@ ALL RIGHTS RESERVED
(C)
The Toro Company
MINNEAPOLIS,
MN
1987
55420 -USA
Reference Information
Safety Information Specifications 2
Tool Requirements
TABLE OF CONTENTS
Page
1
5
Service Procedures
Section
Section 2 Fuel System
1
Troubleshooting Maintenance
Carburetor Page
operation 11 removal
disassembly 14
reassembly 16 installation 18 adjustment 18
Fuel Tank
removal 20 installation 20
6
8
14
Primer Pump
properuse 21 operation
disassembly 22 inspection 22
reassembly 22
Fuel Pickup Tube and Filter
service 23
Fuel Cap
operation 23 disassembly 24 inspection 24 reassembly 24
21
Service Procedures (cont'd)
TABLE
OF
CONTENTS
Page
Section
5
operation airgapadjustment coilremoval coil installation
Recoil Starter Recoil Mechanism
operation removal disassembly reassembly
installation
Starter Pulley
removal installation
Clutch and lsomount Clutch Shoes and Flywheel
operation disassembly
inspection
25 27 28 29
30 30 30 31
32
33 33
34 34
34
Section
6
removal reassembly
Clutch Drum and Housing
disassembly reassembly
lsomount
Engine
(TC4000
operation
disassembly reassembly
operation removal
disassembly cleaning after disassembly inspection
and TC5000 only)
from
drive tube
35 35
35 35
36 37
37
38
40
41 42
43
Service Procedures (cont’d)
Section 6 Engine (cont’d)) Page
TABLE
OF
CONTENTS
Section
Section
8
7
reassembly installation on drive tube.
Control and Grip Control
disassembly 46
reassembly
Grip
removal installation
Handle
TC3000
removal from drive tube 48 Installation on drive tube. 48
adjustment
TC4000
removal from drive tube installation on drive tube. adjustment.
44
45
48 48 49
Section
Section
9
10
TC5000
removal from drive tube installation on drive tube.
adjustment.
Shield
removal from drive tube installation on drive tube. mounting cutter knife on shield
Gearbox
removal from drive tube
installation on drive tube. sealremoval sealinstallation
49
50
50
52
52
53
54 54
Service Procedures (cont’d)
Drive Shaft
Drive
TABLE
removal 56 installation 56
Tube
removal 56 installation 57
OF
CONTENTS
Section
Section
Section 14 Plastic Fixed Line Head
12
13
Leeco@ Manual Line Feed Head
sped
removal 58 linereplacement 58
installation 58
Head
disassembly 59 inspection 59 reassembly 59
Kaaz@ Manual Line Feed Head
head disassembly 61 linereplacement 61 headreassembly 62
linereplacement headremoval 63 headinstallation 64
63
Section 15 Metal Fixed Line Head
linereplacement headremoval headinstallation
Section 16 Tap and Trim@ Head
Spool
removal 67 linereplacement 67 installation 67
65
65
66
Service Procedures (cont’d)
TABLE
OF
CONTENTS
Section
Section 17
Section 18
Section 19
Tap and Trim@ Head (cont’d)
Head
disassembly 68 inspection 68
reassembly 68
Metal Blades
removal 69 installation 69
Harnesses
assembly
Spark Arrestor Muffler
removal 71 installation 71 maintenance 71
Page 16
70
SAFETY INFORMATION
This manual is intended
this safety symbol manual only. The safety instructions provided
means WARNING CAUTION product only. The individual Operator’s Manual will
A
INSTRUCTION Read the instruction TC3000. because Failure to comply with the instruction may result
PERSONAL SAFETY contain safety information on the operation of the
it
has to do
in
personal injury
with
or
FOR
or
safety.
death.
YOUR SAFE
manual are for the troubleshooting and service of the
Operator’s Manuals with complete operational safety instructions are available through:
as
TC4000.
Minneapolis,
or TC5000.
The Tor0 Company
Publications Department
81
11
Lyndale Avenue South
MN
TY...
a service and repair
55430
U.S.A.
in
this
I----
Avoid possible explosions Avoid unexpected starting of the engine Store fuel in a container designed for gasoline and Always disconnect the spark plug wire before never smoke while working around gasoline. attempting any cleaning, adjustment or repair.
Avoid fires Avoid contact with a moving cutter head Never allow the trimmer engine closer than one meter Always stay clear of the cutter head when the engine (three feet) to any combustible material. is running. The clutch is a mechanical device which
Avoid accidental misuse of fuel Always store fuel in an approved container that is properly labeled.
Avoid falls Always wipe up spilled fuel or oil.
Avoid asphyxiation Never operate an engine proper ventilation.
in
a confined area without
could fail. Do not rely on
from turning. Avoid blindness
Always wear eye protection when repairing or running a gas trimmer.
Avoid hearing
Wear ear protection when running a gas trimmer.
loss
it
to keep the cutter head
1
Engine Specifications
SPECIFICATIONS
TC3000
and
TC4000
Service Specifications
2
SPECIFICATIONS
(cont'd)
TC3000 and TC4000 Service Specifications (Cont'd)
Piston Ring
Side
Clearance
0.020
(0.0008
TC5000 Service Specifications
to
to
0.060
0.0024")
mm
0.150
mm
.
(0.0059")
3
SPECIFICATIONS
Carburetor Specifications
Item Standard
Throttle Valve Needle Jet
1.4
to 1.6mm
(0.055
(cont'd)
to
0.W')
Idle Speed Adjusting Screw Adjust
Fastener Torques
Fastener
Crankcase Screws
(2500
kgm
0.4
to
so
0.5
idle
200
is
rpm
(3000
on
200
TCSOOO)
rpm on TC3000 and
in
Ibs
35 to 43
TC4000
TOOL
REQUIREMENTS:
Flywheel Puller Tor0 part number 41-7650 Dial Indicator
V
Spark Tester Tor0 part number41-7890
Tachometer
Feeler Gauge
Compression Gauge Metric Socket Set Spark Plug Socket #2 Phillips Screwdriver
12
oz.
Ball Peen Hammer
3/8”
Tor0
Drive
part number 42-2730
Magnetic Spark Plug Gapping Torque Wrench Threebond #1104 Tor0 part number
Loctite #242 Tor0 part number Micrometer Snap Ring Plier (inside Hex. Key Set
Blocks & Dial Indicator Stand
Tool
&
outside type)
505-80
505-76
5
TROUBLESHOOTING
Engine Does Not Produce Spark
Engine
Floods
During Starting
Engine Not Getting Fuel
crankcase
leak
TROUBLESHOOTING
Engine Lacks Power
Engine Has Low Compression
(cont’d)
Remedy
Engine Backfires (indicated by burnt air cleaner element)
Trimmer Vibrates Excessively
I
7
Maintenance
Air
Cleaner
Servicing of the air cleaner is recommended after every
25
hours of operation or more often in very dusty
conditions.
See
Figure
1.
Maintenance Muffler Decarbonizing the muffler is recommended after every
50
hours of operation or
drastically. See Figure
if
engine speed decreases
2.
AIR
1.
Remove the
FILTER
FILTER SCREEN
Figure
two
screws securing the air cleaner
1
GRID
FOAM FILTER
cover to the trimmer
Carefully remove the filter grid, foam filter and filter
2.
screen.
Figure
1.
Remove the three screws securing the muffler
2
cover to the trimmer.
2.
Remove the
two
nuts securing the muffler to the
engine.
3.
Rotate the engine crankshaft until the piston totally covers the exhaust port. Clean the exhaust port
area by using a clean flat piece of hard wood.
Remove all loose particles.
Wash the foam filter in a soap and water solution
3.
and dry thoroughly. damage replace
4.
Saturate the foam filter with 5ml (one teaspoon) of
SAE
30
oil, then squeeze to distribute the oil evenly
If
the filter shows any sign of
it.
and to remove excess oil. The element should be damp but not wet.
Wash the filter screen in a clean solvent and air dry.
5.
If
the filter screen shows any signs of damage,
replace Reinstall the air cleaner components as shown in
6.
Figure
it.
1.
Note that the flat side of the filter grid
faces the foam filter. Tighten the air cleaner screws to
7.
(13
to
17.5
in Ibs)
0.15
to
0.20
kg m
8
IMPORTANT
the exhaust port. Stay clear
will
not be damaged.
4.
Inspect the inside of the muffler for excessive carbon buildup.
Use extreme care
If
carbon buildup appears to be
when
of
the piston
cleaning
restricting the exhaust flow, replace the muffler. Otherwise, clean the muffler by holding
it
vice grips and heating with a propane torch. Once
hot, break the carbon loose by hitting the muffler on
a
hard surface. Ensure that the muffler is
completely free
of
all carbon particles before
reinstalling.
5.
Reinstall muffler using a new muffler gasket and tighten all fasteners securely.
6.
Reinstall
the
muffler cover as shown in Figure
so
with a
1.
it
Maintenance Spark Plug
The TC3000, BMGA spark plug or the equivalent. Correct gap is mm
(0.024-0.028”).
for the spark plug is
1.
Stop the engine and pull
2.
Clean around the spark plug and remove the spark plug from
IMPORTANT: Replace spark plug.
TC4000
and the TC5000 each use an
The recommended servicing interval
25
hours of operation.
off
the spark plug wire.
the
engine using a 19mm
a
cracked, fouled or dirty
Do
not sand blast, scrape or clean
(3/4")
NGK
0.6-0.7
socket.
electrodes because engine damage could result
from
grit entering the cylinder.
3.
Set the plug gap to 0.6-0.7mm Figure
3.
I3
(.024-.028”)
.024
(0.6
0.7
See
.028"
mm)
5.
Push the pickup assembly back into the tank and install the gas cap.
Figure
4
Maintenance Cooling System Before each use, visually inspect the cooling air inlet, the
cooling fins, and the openings around the muffler for
debris. Obstruction of these areas could lead
to
overheating and possible engine damage.
Figure
Reinstall the plug and gasket in the engine. Tighten
4.
to
1.2
kg m
(1
04
in Ibs)
3
Maintenance Fuel Filter Fuel filter replacement is recommended after every
hours of operation.
1. Drain the fuel from the fuel tank into a container designed for gasoline. Start the engine and run at idle speed until
it
stops and all fuel is
expended.
2.
Remove the fuel tank cap. Insert a clean wire with
a
hooked end into the tank and hook the pickup tube above the filter. Pull the filter and hose fuel tank opening. See Figure
3.
Remove the filter by holding the black tubing and
pulling the filter straight
4.
Replace the filter assembly.
4.
off.
out
let
the
25
to
Be careful not
damage the cooling fins during
cleaning.
Maintenance Trimmer Implement
The trimmer implements require no lubrication. However, cleaning of the implement and the drive shaft area is recommended after every More frequent cleaning may be required very tall grass or
if
the implement area gets excessively
25
hours of operation.
if
trimming in
hot.
to
the
Refer
Table
of
Contents for the location of information on removal and cleaning of your particular implement.
Maintenance Preparation
for
Storage
The following procedure is recommended to ensure proper operation of the trimmer before storage of more than a month.
it
1.
Drain
the
fuel from the tank into a container designed for gasoline. Start the engine and run at idle speed until
it
stops and all fuel
let
it
is
expended.
2.
Remove dirt and grime from external parts of the
trimmer. Ensure that the cooling fins are clean.
3.
Pull
the spark plug wire off the spark plug. Clean
so
around the plug
that debris will not fall into the sparkplug hole when the plug is removed. Remove the spark plug.
9
Maintenance Preparation for Storage (cont’d)
4.
Pour 5ml (one teaspoon) of two-cycle oil into the spark plug hole This will prevent corrosion from
damaging internal engine components.
5. Pull the recoil starter handle several times to distribute the oil throughout the engine.
6.
Reinstall in Ibs).
the
spark plug. Tighten
DO
NOT CONNECT
it
PLUG
to
WIRE
1.2
kg m
TO
(104
THE
SPARK PLUG.
Maintenance Gearbox Lubrication Lubrication of
after every
1.
Remove the cutter implement from the trimmer. Refer to the Table
the
cutter head gearbox is recommended
40
hours of operation.
of
Contents for the location of information on removal of your particular implement.
2.
Remove the gear case cap and the spacer sleeve
from the drive shaft. See Figure
5.
3.
Clean any debris from under the gear case cap.
4.
Clean the grease fitting, then fill a general purpose number
the
2
lithium base grease until grease is forced out from around the drive Shaft.
5. Reinstall the spacer sleeve and
the
on the drive shaft.
6.
Reinstall the trimmer implement See the Table Contents for the location of information on installation of your particular implement.
gear case with
gear case cap
of
Figure
5
10
SECTION
Carburetor Operation
The carburetor used on the TC3000, TC4000 and the TC5000 is a diaphragm style carburetor. alternating pulses from the crankcase to pump fuel from the fuel tank to the carburetor.
It
1
uses
CARBURETOR
n
To adequately describe the function
is necessary to break its operation down into three
systems:
The Diaphragm Pump
Fuel Metering and Mixing System
The Primer System
Carburetor Operation The Diaphragm Pump
The diaphragm pump requires alternating positive and
negative air pressures working upon
fluctuate and perform a pumping function. The source of
the positive and negative pressures is the lower
crankcase where these pressures are alternately being created by the up and down movement of the piston.
Transfer of these pressure pulses is accomplished by a
passage which leads from the lower crankcase to a point
just below the intake port. See Figure
of
the carburetor,
it
in order to
6.
it
PULSE PASSAGE
The pulses vary with the movement of the piston.
piston moves upward, vacuum is created which pulls the diaphragm toward the pulse hole. This movement results
in
three things happening on the pump cover side of the
diaphragm. See Figure
Figure
8.
PULSE
7
HOLE
As
the
PULSE
PASSAGE
Figure
From there, the passage leads through the intake flange and into the carburetor. It terminates in the diaphragm chamber at a point called the pulse hole. See Figure
6
7.
FUEL
PUMP
COVER
FUEL
INLET
CAVITY
Figure
8
1.
The oulet flapper valve cover. This seals the outlet passage to ensure that fuel is drawn only through the fuel inlet.
is
drawn toward the pump
11
Carburetor Operation
The
Diaphragm Pump
(cont’d)
2.
The inlet flapper valve is pulled open to allow fuel
to flow from the fuel line and into the fuel inlet cavity.
3.
Fuel is drawn into the fuel pump cavity.
As
the piston moves downward, another sequence
occurs which pumps the fuel from the pump cavity
into
the
the main diaphragm cavity. See Figure
9.
FUEL PUMP CAVITY
INLET
NEEDLE
Figure
1.
The exhaust stroke sends a positive pressure pulse
9
to the pump diaphragm which pushes the
diaphragm toward the pump cover.
2.
The positive pressure in the fuel pump cavity seals the inlet flapper valve to prevent fuel from being forced back into the fuel line.
3.
The outlet flapper valve is pushed open.
4.
Fuel is forced out of
the
pump cavity and past the
inlet needle.
I
MAIN
DIAPHRAGM
CAVITY INLET
Figure
10
NEEDLE
Carburetor Operation Fuel Metering Mixing
With the main diaphragm filled with fuel, the carburetor
meters the amount going into the engine by using the high speed mixture screw and the needle entering the intake port
with air to further atomize
of
the engine, the fuel is mixed
it
and increase its
jet.
Before
combustibility. The metering and mixing operation is described below:
See Figure
11.
n
THROTTLE VALVE
SECONDARY NEEDLE JET
NOTE:
The inlet needle is spring loaded in the
closed position. The spring pressure is very slight and is easily overcome by the force of the fuel coming through the passage.
5.
The fuel enters the main diaphragm cavity. Figure
NOTE:
reservoir
10.
The main diaphragm serves only as a
so
that fuel can be properly metered before entering the venturi. It does not do any pumping of fuel during normal operation.
6.
Once the positive pressure is gone, the needle
valve is reseated. This allows fuel to
be
drawn from the sealed main diaphragm cavity and into the carburetor throat on the intake stroke.
See
12
HIGH SPEED MIXTURE screw
CAVITY
Figure
1.
On the intake stroke, vacuum in the carburetor
11
throat draws fuel from the main diaphragm cavity. Note that as the intake stroke begins, the main diaphragm cavity is filled with fuel and that the diaphragm is bowed toward the cover.
Carburetor Operation Fuel Metering & Mixing (cont’d)
2.
The fuel is drawn through the hole in the top of the
main diaphragm chamber and past the high speed mixture screw. The high speed mixture screw
regulates the maximum amount of fuel
that
enter the carburetor throat.
3. The fuel is then drawn past the secondary needle which is attached to the throttlevalve.
It
moves with the throttle valve and regulates the amount of fuel allowed into the carburetor throat in proportion with the throttle setting.
4. The
venturi
is the portion of a carburetor throat that
is narrowed in order to increase air velocity. On the
TC1000 carburetor, the venturi size is variable and
is controlled by the postion See Figure
12.
of
the throttle valve.
can
6.
To better atomize the fuel, an air correction
jet
was added. The air correction jet allows filtered air to enter the carburetor throat perpendicular to the
normal air flow. This action creates turbulence in
the
venturi area and helps mix the fuel with air as
it
enters the carburetor throat.
7.
The air/fuel mixture enters the engine.
See
Figure 13.
Carburetor Operation The Primer System The TC3000, TC4000 and TC5000 trimmers use a primer
system that ensures fuel is present throughout the fuel system. When properly used, this primer system should not induce flooding.
The recommended procedure for priming is as follows: See Figure
14
THROTTLE
VALVE
Figure 12
5.
The vacuum in the venturi area draws the fuel past the secondary needle jet and into the carburetor throat.
VENTURI
CHOKE
OVERFLOW
LEVER
TUBE
\
Figure 14
Push the tickler button fully inward.
Manually pump the primer pump until a small amount of fuel is emitted from the overflow tube. Stop pumping the primer pump and release the tickler valve. The engine is now ready to start.
AIR
CORRECTION
Figure 13
JET
The operation
Figure 15.
1.
2.
13
of
the primer system is as follows:
When the tickler valve is depressed slightly, the inlet needle is unseated.
Depressing the tickler valve fully keeps the inlet needle unseated and also opens the overflow needle.
See
Carburetor Operation The Primer System (cont’d)
2.
Pull from the carburetor the overflow line and the fuel feed line. Remove the carburetor with attached throttle wire. Next, remove
the
two
screws with lock washers, that secure the carburetor onto the intake flange. See Figure
17.
MAIN
DIAPHRAGM
CAVITY
OVERFLOW
3.
Pumping the primer pump forces fuel into the
NEEDLE
Figure
TICKLER
15
BUTTON
entire fuel system. This action ensures that the fuel line, diaphragm pump, and main diaphragm cavity are all filled with fuel.
NOTE: If the tickler valve is not fully depressed during priming, the overflow valve will not open and fuel will be forced into the carburetor throat thereby flooding the engine.
4.
Releasing the tickler valve seats the overflow valve and the inlet needle. At this point the engine is ready for starting.
Carburetor Removal
1.
Remove the
two
screws with flat washers and lock washers, securing the air cleaner assembly and remove the assembly. See Figure
16.
Figure
3.
Remove the intake flange, gasket and insulators.
4.
Remove the
assembly
two
to
the cylinder and carefully remove the
17
screws securing the intake
intake flange, insulator gasket, insulator and plate. IMPORTANT: Before removing the intake
flange, note the position of the pulse orifice through the flange: this orifice should be positioned toward the fuel tank as corresponding orifice
in
the carburetor. The
it
matches a
intake flange can be incorrectly positioned. This will result
NOTE:
The screws securing the intake flange may
in
fuel starvation.
have become heat seized and difficult to remove.
They can be loosened by firmly tapping the
screwdriver into the screws. During reassembly, a sparse application of anti-seize compound to
these threads can prevent future heat seizure.
Carburetor Disassembly
1.
Separate the carburetor from the throttle by unscrewing the mixing chamber cap and removing the throttle cable and the attached throttle valve, needle jet, throttle spring and spring retainer. See Figure
18.
Figure
16
14
Figure
18
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