Toro 4250 User manual

4250, 4505, 8605 AND LATER COMPLIANT MOWERS
All LawnBoy Compliant Scamp ModelMowers
feature a Flywheel Brake system. It will stop the
bladefromturningwithin
3 secondsafterthe
operator releases the bail. The engine also stops
at the same time.
Adjustmentsand servicing
of the Scamp self-
propelledmowers arevery differentfromall
previous models of self-propelled mowers.
SAFETYWARNING: Before anyad-
justmentsor repairs are attempted,
disconnect andremovespark plug to
prevent starting.
INSTALLING CONTROL
ROD
1. Placeretainer clipon clutch arm with long side
of clip on the inside of clutch arm.
2. Align hole in clip with hole in arm and assem-
ble lower end
of the control rod in hole.
3. Turn (swivel)long end of clip up and snap into
position on lower control rod as shown.
SCAMPMODELS
SERVICINGANDADJUSTMENTS
SELF-PROPELLED
SAFETYWARNING:The lowerself-
propelcontrol rodmust be assembled
to clutcharm as shown.If not theself-
propelmechanism will not return to
neutral when thecontrol lever
is
released fromthe engaged position.

SCAMPMODELS
SELFPROPELLED
SERVICING AND ADJUSTMENTS
4. With the control handle in “neutral”(free) posi-
6. Secureupperand lower control rodstogether
tion as shown. withthe clampscrew as shown.This screw should
be tightened securelyby hand.
5. With the clutch arm resting on the handle and
wheel bracket as shown.
SAFETY WARNING: Improper tighten-
ing
of clamp screw on control rod may
result inoperator
loss of drive control
mechanism.
NOTE:
To put mower in motion, pull
upward oncontrol handle andhold in
drive position.
To stop forward motion
of mower, release control handle.
Mower drive mechanism functions
only when the control handle is held
in
“DRIVE” position.
19.42 SERVICE BULLETIN REFERENCES
1983

SCAMP MODELS
SELFPROPELLED
SERVICING AND ADJUSTMENTS
DRIVE ROLLER ADJUSTMENT
1. Withthecontrolhandlein “Neutral”, placeboth 2. Loosenboltandnutlocated indrive roller gap
rearwheel heightadjusters in #1 (lowest) cuttingadjustingslotoneachside
of drive roller bracket.
position as shown.
A gap of 3/16” should appear
betweenthe drive rollersand tires. 3. Move the drive rollerbracket upor down to
ob-
tain thenecessary 3/16’’ drive roller gap. Hold
bracketin position and tighten both bolts and nuts
securely.

SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLEDDRIVE BELT
V BELTREMOVAL OR REPLACEMENT
SAFETY WARNING:To prevent start-
ingengine, disconnect sparkpluglead
and remove spark
plug.
The “V” belt used onthe utilityself-propelledmodel
mowers
is a SPECIALBELT. DO NOTUSE A
SUBSTITUTE. Itwon’t work as WELL
or as LONG.
To remove the belt:
1. Remove four belt guard cover screws and
remove cover.
2. Turn mower up on side and remove nut, blade
andcollar. Removethreeboltssecuringmuffler and
crankshaft support. Remove muffler.
19-44 SERVICE BULLETIN REFERENCES
1983

6. Remove belt from driven pulley and slide shaft
assemblytothe right.Removebelt frommoweras
shown.
SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLEDDRIVE BELT
SAFETY WARNING: To prevent start-
ing of engine, disconnectand remove
sparkplugprior to removingthe
engine.
3. Remove three bolts securing engineto muffler
plate andremoveengine.
NOTE: Do not remove mufflerplate
from housingwhen removingengine.
4. Removeengine and remove drivebelt fromdrive
pulley.
SAFETYWARNING: Do notoperate
mower with belt guard removed.
5. Remove roll pin from left hand drive roller and
remove roller.

SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLEDDRIVE BELT
NOTE: After thebelthas been re-
moved, examine for broken, cracked or
misalignedpulleys.The conditionand
the wear pattern of the belt will pro-
vide cluesfor the above possibilities.
Replace damaged or worn pulleys.
7. The crankshaft pulley (drive pulley) is secured
tothe crankshaftwith aSPECIALslotted set screw.
Theend
of this screwlocates in ahole in the
crankshaft. The correct position and tightness is
veryIMPORTANT.
If nottightened securely,
damage to the pulley, crankshaft and premature
wear
of the drive belt will result.
NOTE: ApplyOMC Ultra-LockPart No.
388517 tothreadsof set screwpriorto
installation.
8. When reinstallingpulley to crankshaft, the side
of the pulley with set screw is the lower side.
If
assembledupsidedown (set screwon top)
misalignment and interference of pulley operation
will result. Alwayscheck pulley for damage.
Replace
if necessary.
19-46 SERVICE BULLETIN REFERENCES
1983

IDLER
PULLEYS TOP STRAND
1
DRIVE-BOTTOMSTRANDENGINE
SHAFT DRIVE
PULLEY PULLEY
SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLEDDRIVE BELT
SAFETY WARNING
SAFETY WARNING: Incorrectdrive
belt installation may allow mower to
operate in reversedirectioncausing
injury to the operator or bystanders.
Assemble drive belt as shown.
INSTALL BELT AS SHOWN
FOR PROPERPULLEYROTATION
11. Check the condition of thedrive shaft, bronze
bearings, and sleeve.
If signs of damage or wear
appear, replacethem.
SERVICE BULLETIN REFERENCES ................................................................................................................................................................... 19.47
1983

SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLEDDRIVE BELT
12. Reassemble the drive shaftintothebearing
and slideit to the leftasfar as possible. Assemble
the washer and drive roller on the drive shaft.
INSTALLBELT AS SHOWN
FOR PROPERPULLEYROTATION
13. The drive rollers mustbe properly installed to
utilize the self-cleaningfeature. Properinstallation
is with the vee pointing toward the wheel.
14. Using anew roll pin, assemble thedrive roller
tothedrive shaft. Usea5/32”
or larger drift punch,
drivethe rollpin intoplace, flush with the outersur-
face. Neitherend should protrudebeyondthe roller
surface.
15. As you face the front of the mower, twist the
forward end ofthe belt1/4turn counter clockwise
and assemble on the enginedrive pulley. Assem-
ble engine on muffler plate andsecure with three
bolts.
16. Release springtensionon idler pulleys and
assemble belt on drive shaft pulley. Reassemble
idlerpulleyspringand rotatethebelt several revolu-
tions. Check to make sure the belt iscenteredon
the’ pulleysand TURNING IN RIGHT DIRECTION.
Note directionof arrow onlarge pulley in illustra-
tion above.Check andadjust belt tension
if
necessary. Referto BELT TENSION ADJUSTMENT.
NOTE When replacing either of the.
beltidler assemblies,useidler kit part
no. 682374for the top and kitpart no.
682564 onthebottom.
19-48 .... 1983 SERVICE BULLETIN REFERENCES

2. Drive beltshould be checked to insure that
proper tensionexists inorder to prevent premature
belt failure. Lift floatingidler from theupper strand
of
“V” belt. Belt will then become loose.Set
floating idler onto
“V” belt and check clearance
between thetwostrands of the
“V” belt. The
distance between the two strands should not be
less than 112” as shown.
complished by measuring the
distance fromthe
front edge on the height adjuster brackets to the
1/4” diameter gage holes located directlyinfront
of these bracketsas shown.This distance mustbe
the same for bothsides. Before tightening screws
makesure the distancebetweenthe strandsof the
“V” beltisnot less than 112”. Tightenthefour
handlebracketscrewsandthe two sidescrews
securely.Reassemble beltguardto self-propel
mechanismusingscrewspreviously removed.’
SAFETY WARNING
SAFETYWARNING: Do notoperate
mower with belt guard removed.
SERVICE BULLETIN REFERENCES 19-49
1983

SCAMPMODELS
REPLACEMENT AND SERVICING
SELF-PROPELLED DRIVE BELT
LUBRICATION
50 HOURS
1. DRIVEROLLER BEARINGS-Disassemble
rotating shaftcoverfromself-propelmechanismby
removing four screws. Unscrew plug from end of
each drive roller (Point“A”). Fillexposedcavitywith
EQUIVALENT.Replaceplugandtighten untilsnug.
Repeat procedureuntil lubricant appears oncross-
shaft at Point“B”. Reassemblerotating shaftcover
to self-propel assembly.
LAWN-BOY“A” GREASE,PART
NO. 610726 OR
FOUR PLACES
BOLT-PULLEY-ARM-NUT
LOWERIDLERASSEMBLY
PART #682564
LOWER IDLERPULLEY-Permanently lubricated.
No lubrication required.
FLOATING IDLERPULLEY-Do not immerse the
idler pulleyinsolvent. Usea ragcontaining solvent,
clean the holeinthe idler pulleyand the shoulder
bolt thoroughly. Using a small amount of LAWN-
BOY “A” GREASEor EQUIVALENT,relubricatethe
shoulder boltand remount idler pulley assembly in
the same order it was originally.
ASREQUIRED
1. CLUTCH LINKAGE-Apply several dropsof light
machine oil on clutch mechanism at all pivoting
points.
19.50 ...........................SERVICE BULLETIN REFERENCES
1983

SCAMP
BRAKE SERVICING
AND REPAIR
To service and repair theflywheelbrakesystem,
remove the shroud and tank assembly.
(5 Phillips
screws).
Figure 1
Figure 2
Lift spacer from top of shroud base.
Figure, 3
Remove flywheel screen. (3 screws).
Flywheel Removal/Installation
It will be necessary to move theFlywheel Brake
Arm away from the flywheel (pull back oncontrol
bail)to allow removal orinstallationof theflywheel.
Figure 4
Remove flywheel nut.
To breakflywheel looseusea softhammerand rap
sharply down onone of the thick fins while lifting
with other hand on opposite side of flywheel.
NOTE: Do not breakany fins on
flywheel. Itwill be unbalanced and
vibrate.
SERVICE BULLETIN REFERENCES 19-51
1983

SCAMP
BRAKE
SERVICING AND REPAIR
Pull bail backagainstthehandle to releasethe
brake.
Lift flywheel off.
Flywheel Configurations
1983 Flywheels are muchtallerthanprevious
models. As Fig.
5 shows, the visual difference is
quite apparent.
NOTE These newflywheelsare not in-
terchangeablewith those ofprevious
Lawn-Boy models.
1983 PreviousYears
Figure 5 FlywheelHeightComparison
It is important to note that two different materials
are used
on compliancemowerflywheels.
Flywheelsfor all FlywheelBrake modelsare made
of aluminum, but due
to the need for additional
rotating weight (inertia), the Blade Brake Clutch
(BBC) flywheels are made of zinc. The zinc
flywheels are plainly marked as such to prevent
confusion. Be certain you install only thecorrect
type flywheel for the specific mower.
SAFETYWARNING:FlywheelBrake
(ZoneandPRS)andBladeBrake
Clutch (BBC) flywheels are not inter-
changeable. The correct type flywheel
(aluminum or zinc) iscritical to proper
CPSC compliance.
Figure
6 .FlywheelBrakeSystemComponents
1. RetainerClip
2. cup
3. “Pigtail”Spring
4. CircuitSwitch
5. SwitchRetaining Screw
6. AdjustingBolt
7. Locknut
8. Brake Arm
9. Brake Arm Bolt
10. CableRetainerSpring
BrakePad Wear-
FlywheelBrakeArm (with bonded brakepad) must
be replaced
if padwears below .030” at any spot.
.030” Minimum
Figure 7 FlywheelBrakePadWear
19-52 SERVICE BULLETIN REFERENCES

SCAMP
BRAKE
SERVICINGAND REPAIR
To replacethebrake arm, itwill be necessaryto STEP #6
disconnectthebrakecablefromthe engine. Thoroughlycleanthethreads of thebolt and apply
Lawn-BoyScrew Lock, part number
384848 to the
Set theflywheelback on the engine. threads.
Figure 8
STEP #1
Withflywheel in placeandthe bail controlreleased
(out ofoperating position), compress the “Pigtail”
Spring by hand,then removethe Retainer Clip, Cup
and Spring.
STEP #2
Remove the cable from the housing.
Remove the flywheel.
STEP #3
Removecircuit switch adjusting boltand locknut.
(See Fig.
6).
STEP #4
Remove brake armboltand brake arm.(See Fig.6).
STEP #5
Re-assemblecircuit switch adjusting boltand lock
nut into thenew brake arm. Turnitintobracket until
head is against the bracket. (See Fig.
6).
STEP #7
Assemble the brake arm and bolt onto bracket.
Tighten to 5-7 ft. Ibs.
(63-75 in. Ibs.)
STEP #8
Reassemble thecable retainer spring intothe
bracket assembly.
STEP #9
It isnecessary tocheck thebrakecable adjustment
before reinstalling it in the bracket.
Figure 9
STEP #10
To adjust the brakecable, loosen the jam nutand
backit off.Place the brake cable adjustinggauge,
part number 611703over the end of the cable.
Assemble theretainer clip(see Fig.
9) on the cable
against the gauge.
Turn adjusting nut up against thegauge to apply
approximately
5 Ibs. tension.
SERVICE BULLETIN REFERENCES 19-53
1983

SCAMP
BRAKE
SERVICINGAND REPAIR
STEP #2
Placea mark on the plunger atend of gauge. (See
Fig.
11).
STEP #3
Remove the gauge.
Figure 10
STEP #11
Turn jam nut against the adjusting nutand tighten.
Do not permit adjusting nut to turn.
Figure 12
STEP #4
(See Fig. 10).
Use 1/2” Open end wrenches. Pull thebail backagainstthehandleandhold it.
STEP #12
Set flywheel back on the crankshaft.
STEP #5
Turnadjusting boltin untilmark on plunger is flush
with face of switch body.
STEP #13
ReassembletheCable intothe BrakeBracket, then Tighten nut.
reassemble theSpring, Cup and Retainer Clip.
STEP #6
After thebrakecable is reassembled, it is nec-
essary to check the circuit switch adjustment.
NOTE Be sureadjusting boltdoes not
turn.
NOTE Recheck thisswitchadjust-
ment to prevent the plunger from go-
ing in toofar anddamaging the switch
internally.
If it doesnot move in far
enough, the engine will not start.
SAFETYWARNING:Properadjust-
ment
of this switchisnecessary to in-
surethat blade motionstopswithin
the required time.
NOTE
If proper switch adjustment
cannot bemade, checkbrakecable
adjustment (See Fig.
9) asthis will af-
fect correct switch operation.
Figure 11
STEP #1
Place the switch adjustinggauge on theplunger.
19.54 SERVICE BULLETIN REFERENCES
1983

I
SCAMP
IGNITION CIRCUIT SWITCH
TESTING AND REPLACEMENT
Troubleshootingthecircuit switch. STEP #7
‘-Using a driftpunch andhammer, drive the switch
STEP #1 bodyout of the bracket.(SeeFig. 13). Thiswill break
Disconnect both leadsfromthe
C.D. pack.theflangeontheswitch.
STEP #2
Connect a continuity meter or light totheseleads.
STEP #3
Push the plungerin. The meter shouldread “0” or
the light should go out.
STEP #4
Release the plunger. The meter should indicate a
completed circuit or the light will
go on.
If the switch isdefective, it requires replacement.
STEP #8
Assemble thenew switch and lead assemblyinto
the bracket.
STEP #9
Installtheswitch retainer screw.Reconnectthe
two leads onto the
C.D. pack.
STEP #10
Adjust the switch plunger travel with the gauge,
part number 61 1702.Follow steps
1 thru 6 onpage
14.
SAFETYWARNING:Properadjust-
ment
of this switch is necessary to in-
surethatblademotionstopswithin
the required time.
Figure
13
STEP #5
To replacethe switch, itwill be necessary to
removethe flywheelfor accessto theswitch. This
permits the brakearm to swing out of the way.
STEP #6
Remove the switch retainer screw. (See Fig. 6).
SERVICE BULLETIN REFERENCES 19-55
1983

SCAMP
BLADE AND BLADE HOUSING
Figure 1
Assemble muffler onto crankshaft.
Figure 2
Figure 3
A specialtool.crankshaftsupport gauge, part
number
609968 is requiredto position thesupport
correctly
do it doesn’t contact the crankshaft.
Slide the gauge onto crankshaft with the thin wall
of gauge inside of support.
Always assemble the crankshaft supportwith the
flange down towards the blade.
Figure 4
Clean threads on mufflerboltsthoroughly andap-
ply Ultra-Lbck, part number
388517. Installbolts
and tighten to
150-190 inch pounds.
19-56.. SERVICE BULLETIN REFERENCES
1983

The Blade and Hardwareshown beloware usedon
all Lawn-Boy Scamp models.
Figure 5
Torque blade nut to 45-50 ft. Ibs.
NOTE: This Blade and Hardwarewill
fit allpreviousLawn-Boy mowers,us-
ing onlytheBlade Driver andBlade
Nut(as showninFig.
5). Do not usethe
old bladestiffener orwasher with
these new blades.
Figure 6
SCAMP
BLADE AND BLADE HOUSING
Before assembling collar on crankshaft, checkto
be sureitdid not get bent or distortedwhen being
removed.
If so, replace it. Do not use, because, it
will cause vibration.
If the blade nut is to bere-used,clean the threads
thoroughly.
Also clean threads on crankshaft.
Apply
OMC Ultra-Lock, part number 388517 on the
threads. Torque blade nut to
45-50 foot pounds.
NOTE After repairs are completed
alwaystestthemowerforstarting,
running and blade stoppagetime.
The required blade stopping timeis
3
seconds or less.
It isrecommendedtomake
3 tests for
blade stopping time and record each
for future reference.
If itdoesn't stopinthe requiredlength
of time, determine what the problem
is and correct
it.
SERVICE BULLETIN REFERENCES 1983

Zone Start Models
BrakeCableRouting(console)
Tie Wrap Locations
1. Single Tie
2. DoubleTie
RetainerCup Removal
Primer Assembly
19-60
Hoseand Cable Routing
I. Primer Hose
BrakeCable
3. Brake Cable Retainer Clamp
4. SwitchCableClamp
SERVICE BULLETIN REFERENCES

Wire Routing Diagram
Zone (manual)Start
Tubing
SERVICE BULLETIN REFERENCES 19-61

19-62
SERVICE BULLETIN REFERENCES