Lawn-Boy 6230 User manual

LAWN-BOY SUBURBAN WPM SERVICE MANUAL
Table of Contents – Page 1 of 1
1. GENERAL INFORMATION
THIS MANUAL
SUBURBAN MOWER MODELS
GENERAL FEATURES AND SPECIFICATIONS
SAFETY SYMBOLS
MOWER, INTENDED USE
FIRE HAZARD
EXHAUST HAZARD
BEFORE USE
STARTING AND OPERATION
ADJUSTMENTS
REPLACEMENT PARTS
2. TROUBLESHOOTING
3. FUEL SYSTEM
THEORY OF OPERATION
SERVICE
4. ELECTRICAL SYSTEM
IGNITION SYSTEM
FLYWHEEL BRAKE SYSTEM
5. STARTING SYSTEM (MANUAL STARTER)
SERVICE
6. ENGINE (POWERHEAD)
TROUBLESHOOTING
SERVICE
7. DRIVE SYSTEM
CAPSTAN DRIVE
SERVICE
DISC DRIVE
8. MOWING SYSTEM
TROUBLESHOOTING
SERVICE
9. SAFETY FEATURES
CHUTE DEFLECTOR
TRAILING SHIELD
10. TOOLS AND MATERIAL

1 GENERAL INFORMATION
TABLE OF CONTENTS
Page Page
1 . General Information .....................
1 CD Pack ............................ 24
ThisManual
...........................
1 Flywheel ............................ 25
Suburban Mower Models
...............
2 FlywheelBrakeSystem ................ 26
Safety
................................. 3Adjustments ......................... 26
GeneralFeaturesandSpecifications
.... 2 Theory of OperationandTesting ...... 26
Service 27
5 StartingSystem(ManualStarter)29
Service 29
..............................
2 Troubleshooting 7
3 FuelSystem 9
Theory of Operation 10
. ........................
. ........
. ............................
...............................
...................
Service ............................... 11 6 . Powerhead ............................. 31
Fueland Oil
......................... 11 Troubleshooting ...................... 31
ShutOff Valve
....................... 12Service ............................... 31
FuelHose
............................ 12
Primer System12 FuelTank Vent13Air Filter 13
Carburetor 14
Troubleshooting 14
Adjustments 15
Service
............................. 16
Governor 17
Theory of Operation 17
. ...........................
7 DriveSystem37 CapstanDrive 37
Adjustments 37
Service 38
Lubrication 42
DiscDrive 43
Service 44
Lubrication 51
.......................
.........................
.......................
.........................
.............................
..............................
...........................
..........................
....................
............................
........................
Adjustments ......................... 43
..............................
............................
..........................
.................
Adjustments ........................
17 8 . MowingSystem ........................ 53
Service
.............................
17 Troubleshooting ....................... 53
...............................
4 ElectricalSystem 19 Service 53
Ignition System 19 Blades 53
Theory of Operation 19 BladeCollar
55
Troubleshooting ..................... 21 9 . SafetyFeatures ........................ 57
Testing
.............................. 23 10
. ToolsandMaterial ..................... 59
Service
.............................. 24
SparkPlug
.......................... 24
. .......................
...............................
.......................
.........................
..................
THIS MANUAL
This manual wasdeveloped especiallyfor Suburban
model mowers
.
I
Itreliesheavily yetselectivelyonthecomprehensive
Lawn Boy Service Manual
.
Service technicians. especially whenrelatively new
to Lawn Boy’s systemand products. shouldreferto
the LawnBoyService Manualfor further details and
illustrations
.
.
1
....... .......
.
1
. .

SUBURBAN MOWER MODELS
I
Model 6230
I
Model 8430
'- I
Model 6430
Model 8480
GENERAL FEATURESAND SPECIFICATIONS
MOWER
CUTTING WHEEL
MODEL
Staggered
21 "
8430 Staggered
21"
6430 Four Square
20"
6230 POSITION
WIDTH
8480 20" Four Square
DISCHARGE PROPULSION
Rear
I Push
Side Self-Propelled
Side Push
Rear Self-Propelled;
Auto-variable Speed
--
ALL Starter-Manual, TopMounted,Zone Restart
Primer
- Shroud Mounted
Lower Transmission Case
- Die Cast Aluminum
2

~
SAFETY
SYMBOLS
A WARNING This symbolwarnsyou ofstepsthat mustbefollowed toavoidpersonalinjury ordeath.
A CAUTION This alerts you to steps that must befollowed toavoid possible damage to property.
r] NOTE Thishighlightsimportantinformation.
A WARNING Read, understandandfollow all rules inthis sectionbeforeoperating or servicing
Suburban Mowers.
MOWER, INTENDED USE
This mower isdesigned onlyto mow (cut)grass,
or when properly equipped, to bag cutgrass.
Any other use may be dangerous.
FIRE HAZARD
General
Gasoline is extremely flammable and highly
explosive undercertainconditions.Followall
rules listedbelow to avoid fire, explosionand
serious or fatal injury.
Refueling or Mixing Fuel
1. Stop engine.
2. Wait for engine to cool.
3. Do not smoke or allowflame, sparks orany
heat source near gasoline or fuel.
4. Fill outdoors only.
5. Wipe up spilled gasoline and fuel.
6. Replacefuel tank cap securely.
7. Move moweraway from fuelingarea before
starting.
Operation
8. Keepengine free from debrissuch as grass
and excess grease which are fire hazards.
9. Store and handlegasoline only in approved
Storage and Handling
containers.
10. Keep fuel shut-off valve closed.
11. Do not store mower with fuel in carburetor
or tank in an enclosed area with source of
ignition such as afurnace pilotlightor
electric motor.
EXHAUST HAZARD
-1. Never start orrun engineindoors: itwill
produce carbon monoxide which isodorless
and deadly. Keep Heat
and Ignition Sources
Away From Fuel.

BEFORE USE
Mowing Area
1. Clear mowing area ofallforeign objects
such as sticksand stones which can be
thrown and cause severe injury.
2. Keep childrenand animals away from
mowing area.
Clothing
3. Do not wear loose fittingclothingor
accessories (such as jewelry)which could
get caught in moving parts, causing severe
injury.
4. Wear heavy trousers and safety shoes to
give maximum protection.
Mower
5. Disconnectspark plug and make a thorough
inspection of mower several times a year.
6. Checkallnuts,boltsand fasteners,
especially the blade nut (torque is
540-600
in. Ibs. [45-50 ft. Ibs.]).
7. Keep all guards in place at all times.
8. Keep either cover plateor grass catcher
chutewithbag in placeand secure at all
times.
9. Check grass or leaf bagfor wear or
deterioration. Replace
if necessary.
STARTING AND OPERATION
General
1. Teach all safety rules andoperating
instructionstoall users.
Do not allow
children tooperate mower.
Starting
2. Make sure you are ready to mow.
3. Knowyourcontrols;knowhow to stop
enginequickly; be sure controlon self-
propelled models is in “neutral” or locked
out before starting or stopping.
4. Make sure mower is on level ground.
5. Keep a firm hold onhandle.
6. Controldirectionwithhandson mower
handle; never with feet on mower housing.
7. Always push mower, never pull.
8. Onself-propelled auto-mowers, mowata
safe, reasonable speed; on other self-
propelled mowers keep the same pace as
mower.
Do not lag behind orlet mower pull
you.
Mowing
9. Always walk, never run.
10. Be sure of your footing at all times.
(Continued on next page)
4
Keep Fasteners Tight.
L .~-.-~_____---
Start Mower On Level Ground.

STARTING AND OPERATION (CONTINUED)
Terrain and Mowing Conditions
11. Mow across the face of slopes.
12. Do not mowsteep slopes.
13. On unevenground, be careful: housing can
lift upandexposetheblade which cancause
serious injury.
14. Avoidstrikinganythingsuch as a treeor
mowing over any object such as a branch.
15. If anobject is struck and/or the mowerstarts
to vibrate, stop engine, disconnect spark
plug to prevent accidentalstartingand
repairany damage beforerestartingand
operating mower.
16. Mow only
in good light.
17. Never mow in wet grass: footing is unsafe.
Leaving The Operator’s Position
18. Whenever you leavetheoperator’s position,
even for a moment, stop the engine.
19. Never stand infront of a self-propelled
mower when it is running.
20. Keep clear of discharge chute.
21. Keep handsand feet away from moving
parts.
22. Never placehands or feet under mower
housing when blade is turning.
23. Before cleaningthe catcher assembly or
discharge chute,stop engine, disconnect
spark plugand makesure bladehasstopped
turning.
Crossing Non-Grass
Areas
24. Stop engine before crossingany non-grass
area such as a sidewalk or road.
ADJUSTMENTS
1. Disconnectspark pluglead before servicing
engine or mower;and on self-propelled
models, make sure control is in “neutral.”
2. Never rotate blade with hand or foot without
removing spark plug lead.
3.
Do not overspeed engine or alter governor
setting from specification.
4. When adjustingcarburetor, stand to one
side and keep feet and hands clear.
5. Make height adjustments only with engine
and blade stopped.
REPLACEMENT PARTS
Usegenuine OMC parts or parts withequivalent
characteristics such as type, strengthand
material.
Failure todo
so may result in product
malfunctionandinjurytothe operator or
bystanders.
IT’S UP TO YOU. A MOWER IS NO SAFER
THAN THESERVICE TECHNICIAN AND THE
OPERATOR.
Do Not Mow Steep Slopes.
Disconnect Spark Plug Before
ServicingMower.

2. TROUBLESHOOTING
RUNS ROUGH
Crankcase
Screws Loose
Gasket Bad
WON’TSTART
FUEL
SYSTEM
IGNITION
SYSTEM
ENGINE,
AIR INTAKE AND
EXHAUST SYSTEMS

3. FUEL SYSTEM
Fuel Tank - Stores fuel for engine.
VentedFuel Cap
- Vents fuel system to
atmosphere.
Shut-OffValve
- Stops fuelflowto
carburetor.
FuelFilter
- Filtersoutdirt and water,
allowing only clean fuel to enter fuel line.
PneumaticPrimerAssembly
- Forces
compressedairintothefloatchamberwhich
forces fuel into carburetor venturi.
AirFilter
- Keeps dirtfromentering
carburetor with air.
Float
Bowl - Reservoirof fuel for metering
to carburetor throat.
ThrottleDisc
- Varies the volume offuel
and air mixture to engine.
AirVaneGovernor
- Opens and closes
throttle, controllingengine
RPM.
Reed Valves - Permit fuel mixture toenter
crankcase on compression stroke and trap
fuel mixture in crankcase on power stroke.
(Not shown.)

PRESSURE IN
CRANKCASE
Pressure
VACUUM IN
CRANKCASE
Vacuum
LOW PRESSURE AREA
FL
PRIMER HOSE
SEAT
NEEDLE VALVE
FLOATARM
Carburetor
THEORY OF OPERATION
1. Pulling the starter roperotatesthecrankshaft
5. The fuel and air mixture is further mixed as it
which moves thepistonup anddown
in the passes over thethrottle disc; and as the mixture
cylinderand creates alternating pressure and enters the crankcase through the reed valves,it
vacuum in the crankcase. is
in a nearly gaseous state.
2. The vacuum created byupward movement of 6. The float valve is a needle and seat assembly
the piston
in the cylinderopensa reedvalveand activated by a float in thefloatbowl. (Theneedle
air rushes through the throatof the carburetor. rests on the float arm and is held in place by a
3. The carburetor throat is a venturi“tube”, larger
at eachend than
in the center. When air rushes
spring clip.The needle is rubber tippedsothat it
seals well against the seat.)
through a venturi, air pressure at the center
is
When the float bowl is empty, the floatison the
lower(due to
a “law of physics”, Bernoulli’s bottom of the bowl. As fuel enters thefuel float
Theorem). bowl, the floatrises, moving the needle intothe
the venturiallowsthedifference in air pressure
As theengine uses fuel, thefloatdropsandthe
to force fuel fromthefloatbowlupthrough the needle moves off the seat maintaininga
nozzle where it is pickedupbyand mixedwithconstantfuel level inthecarburetor.
the air.
4. A nozzle between the carburetor floatbowland seat, and shutting off the fuel.
10

SERVICE
Fuel and Oil
CAUTION
Lawn Boy mowersare powered by two-cycleenginesthat require a mixtureofgasoline and oil. Failure
to use the right mixture will result in serious engine damage.
SPECIFICATIONS
OIL
Ty Pe
Lawn Boy 2-cycle
A CAUTION
30 not use automotive
oil.
MIXING FUEL
WARNING
1. Gasoline is extremely flammable and explosive
under certain conditions.
2. Mix fuel and refuel mowers outdoors only.
3. Always fill engine when cool.
4. Neversmoke or allow any flame orsource of
heat or ignition near fuel.
1. Use clean, approved containers. (LawnBoy
i
2-1/2 gallon containers are available.)
2. Do not mixfuel in fuel tank of mower.
MIXING SPECIFICATIONS
2-Cycle
Oil Gasoline % Mix
Lawn Boy Oil
8 (U.S.) oz. Can
Other 2 Cylinder Oil
8 (U.S.) oz. Can
3. Pour oil into container.
4. Pour about one quarter of thefuelinto
container and mix well.
5. Release cap slowly to relieve any pressure
and pour remainder of fuel into container.
-GASOLINE
-IC-
NOTE
We recommend pur-
chase of gasoline
in
smallquantitiesto
minimize gum build up
Neverusegasoline
containingalcohol
(seeinformation
below).
ALCOHOL
IN FUEL
Damage
Lawn Boy cannotpresently endorse the use
offuelcontainingalcohol.Evidence
concerning damage to engines is currently
beingassessed.
CAUTION
The followingproblemsmayoccur if
gasoline containing alcohol is used.
1. Deterioration of fuel system.
2. Damage to internalengine components.
3. Lubrication failure, dueto separation of fuel
caused by alcoholabsorbing moisture.
Problems related to use of fuel containing
alcohol are not theresponsibilityofLawn
Boyand may not be covered under
warranty.
FuelSource
The presenceof alcohol ingasoline maynot
beadvertised. If you haveany doubt, do not
use the gasoline.
11

Shut Off Valve
Checking Flow
Removefuel hose, open valve and observefuel
flow throughvalve.
Replacement
damaged.
1. Replacefuelshut off valve assembly if
NOTE
Be carefulwhenreinstalling valve to tank
with spring clip.
Fuel Hose
A WARNING
Do not substitute inferior fuel hose: it may
deteriorate prematurely,cause leakageand
explosion or fire.
PrimerSystem
Checking Operation
1. Disconnect primer hose at carburetor.
2. Coverhole inprimerbulb whilepressing
primer bulb.
A. If air can be feltat endof hose, systemis
operating.
B. If no air can befelt at end of hose,
remove assembly and replace parts as
necessary.
Service
1. Disconnect primer hoseat primer.
2. Remove locknut andremoveprimer
3. Replace partsas necessary.
4. Reinstall primer assembly andreattach
assembly.
primer hose.

e HOLE
CAP
NOTE
Fuel tanks are vented through avent hole in
thetank capto prevent vacuumforming and
stopping the flow of fuel.
TROUBLESHOOTING
Symptom
Engine stops after
running a short
time, can be re-
started
in a few
minutes but
symptoms
will reoccur.
Cause
Blocked vent
hole.
Remedy
Clean vent
hole. Check
fuel source.
TROUBLESHOOTING
Symptom
Power
loss.
Engine smokes.
Cause
Dirty element.
Dirty or
fuel
saturated
element.
Remedy
Clean and
oil element.
Clean and
oil element.
Instruct
customer
on starting
procedures.
Cleaning
1. Loosen clip (bail) and remove filter element.
2. Wash filterelementwithkeroseneor
3. Squeeze dry.
4. Work 10 to 15 drops of oil intoelement.
detergent in water.
Do not operate engine without filterelement
or with a dry element: enginelife willbe
shortened.
5. If not installed, install plastic plugs (PN 61 1545) in air filter box to keep dirt out.
6. Reinstallfilter element so that it iseven,centered in box andsothat thesidesare in “original”position (to
prevent any imbedded particles on intake side from entering carburetor).
13

Carburetor
TROUBLESHOOTING
Problem
Engine won't run.
Engine runslean,
starved.
Engine runs rich.
Engine runs erratically.
Engine stalls,
hard restarting.
Possible Cause
Spring Clip defective.
(Needle stuck shut.)
Nozzle filter not installed.
(Small dirt particlesare entering
carburetor.
Spring Clip defective.
(Needle sticking.)
Float Arm set too low.
Needle andSeat mismatched.
(Fuel supply won't shutoff.)
Float Arm set too high.
Float sticks. (Pivot pin bent,
corroded, or tight inbody.)
Governor sticking.
Float is striking nozzle.
Float is soaked with fuel.
Carburetor adjustedlean.
Nozzle Filter not installed.
(Small dirt particlesare entering
carburetor.)
Remedy
Replace clip and needle.
Clean nozzle and replace
filter.
Replace clip.
Reset float arm.
Replace assembly.
Reset float arm.
Replace pin or loosen pin
to hinge joint.
Check governor.
Repair or replace.
Replace float.
Replace float.
Adjust carburetor.
Clean bowl and nozzle.
Install clean, nozzle filter.
14

ADJUSTMENTS
1.
2.
Start and run enginefor3to
5 minutesto 3.
warm it up tonormal operatingtemperature.
Withenginerunning in “normal”(atabout 4.
3300
RPM) turn needle valve slowly
clockwise approximatelyl/6th of aturnat a
time usingLawn Boywrench (PN612231)or
1/4” open end wrench, until engineruns
smoothly.
NOTE
Always adjustgovernor before adjusting
carburetor
so that enginespeed is incorrect
R.P.M. range.
NOTE
Any newor rebuilt carburetor requires final
adjustment before putting mower into
service.
Turnneedle valve counter-clockwise
approximately 1/6thturn.
Shutoff engine, restart immediately, without
priming: engine should start within
2 pulls. If
it does not, turn needle 1/6th turncounter-
clockwise to richen mixture slightly.
NOTE
NOTE
Thefollowing stepensureseasystarting and
smooth running when cold.
Engine should
4 cyclea little undernoload;
and
2 cycle when under fullloadcutting
grass.
5. Recheck governor adjustment.

----
Measuring Float Height
Adjusting Float Height
NOZZLE
CARBURETOR
BODY
Service
NOTE
For information on how the float and valve
system works and on diagnosisof problems
(seeTheory
of Operationand
Troubleshooting
in this section).
Disassembly and Replacement
1. Remove carburetor from engine.
2. Remove float bowl.
3. Replace needle, seat and spring clip as an
assembly
if any part is worn ordamaged.
4. Remove adjustment needle and nozzle.
5. Removefloatandcheckcondition:replace if
saturatedwithfuel, damaged or if glossy
epoxy sealer is dull.
NOTE
Cleaning float with solvent will not restore it
to operating condition.
6. Check pinclip on float arm byturning
carburetor: replace clip
if it falls off.
Adjustment and Reassembly
1. Check thattop of float is7/16-15/32 inch
above edge of carburetor body, taking two
measurements
90° apart.
Innext step,
do notputpressure on float
itself or youmay damagetipof inlet needle.
2. Adjust, if necessary, bycarefullybending
3. Install nozzle and torque to 18-20 in. Ibs. (2
4. Install a cleannozzle filter.
float arm.
ft. Ibs.).
A CAUTION
Do not forceneedleagainstseatas itcan be
damaged.
5. Turn needle valve in slowly, clockwise,
using Lawn Boy wrench (PN612231) or
1/4" openendwrench, untilit seats
lightly.
6. Turnneedlevalvecounter-clockwise
1-1/2 turns.
16

Governor
THEORY OF OPERATION
The shaft of the governor airvane isattached to
the throttle discofthe carburetor
so thatairflow,
created by the flywheel turning, moves the air
vane and opens or closes the throttle.
ADJUSTMENTS
NOTE
Each “click”onthecollar represents
approximately
50-75 R.P.M.
1. Turncollarclockwiseto increase spring
tensionand R.P.M. orturncounter-
clockwise to decrease springtensionand
R.P.M.
2. Use a tachometer to checkthatengine
R.P.M. is
3100 to 3300 inthe normalsetting.
SERVICE
Removal
1. Removecarburetor and governorassembly.
2. Disconnect airvane shaft from throttle disc
carefully, using needle nose pliers.

!
I
I I
\
\
\
\
AIR VANE
Inspection and Repair
1. Inspectallparts for wear and replace as
necessary.
Installation
1. Assemble air vane shaft to throttle disc so
that ends of springare in holes of collar as
shown.
2. Install carburetor and governor assembly.
3. Adjustgovernor as outlinedon previous
4. Check that carburetor is adjusted correctly
page.
(see Carburetor in thissection).
18

4. ELECTRICAL SYSTEM
Ignition System
THEORY OF OPERATION
The ignition system consists of asolid state
electronic,
CD Pack; flywheelwithabuilt in
permanent magnet; and a spark plug.
NOTE
CD Pack replaces the breaker points,
breakercamandspark advanceassemblyof
a conventional electro-mechanical system.
As theflywheelmagnetpassesthe CD pack, AC
voltage is induced into the charge coil.

MAGNET
RECTIFIER
SPARK PLUG FLYWHEEL
CRANKSHAFT
AT \
5° BTDC
TheACvoltage passes through a rectifierthat
transformsit into DCvoltagewhich
is then stored in
a capacitor.
Atlower speeds, theflywheelmagnetinduces a
small charge
in the trigger coil which triggers the
SiliconControlledRectifier (SCR) allowing easy
starting
in a “retardedfiringposition,”
approximately
5° Before TopDead Center(BTDC).
RUNNING LEG
25° ADVANCE
ROTATION
CRANKSHAFTAT
25” BTDC
Athigher speeds, about 800 RPM, theflywheel
magnets
induce a largeenough charge in the trigger
coil to “trigger” the
SCR rectifier in the “advanced
firing position”
of approximately 25° BTDC.
CHARGE RECTIFIER
When the SCR is triggered or “opens”, up to 300
volts stored in the capacitortravels to thespark coil
where it isstepped up toasmuchas 30,000 volts and
is dischargedacrosstheelectrodes of the spark
plug g.
20