Toro 8125 User manual

Fig.1
The model 8125 isnew. Itfeatures rear discharge
with adiecastaluminumhousingand is agear
drivenself-propelledmower.Fig. 1.
Itis a zone startmodelwiththeflywheelbrake
system.When the bail isreleased, both the engine
and blade will stop within the3-secondtime limit.
Anotherfeature is anadjustabledrivenpulley
which controls ground speed. It is located under
the pulley cover.
SAFETY WARNING:
Disconnect the spark plug lead.
Remove two screws and lift cover off. Fig. 2.
.Fig. 2
With the engine operating at3200 rpm,the ground
speed can becontrolled tooperate at 2.4, 2.6, 2.8,
3.0 or 3.2 mph.
MODEL 8125 SERVICING AND REPAIR
CHANGING GROUND SPEED.
Fig. 3
Loosen the nuton the idler pulley bracket which
will release the tension on the belt.Removethe nut
and thickwasher fromthe top of thedriven pulley.
When a spacer or spacers are not used, they are
storedontop
of thepulley under thenutand
washer.Fig. 4.
Fig. 4
SERVICE BULLETIN REFERENCES 20-1
OCTOBER 1984

Withno spacersbetween thepulley halves, the
ground speed is 2.4 mphat 3200 rpm.Add
one
spacer
between thepulley halves, the speed in-
creases to 2.6 mph.
Twospacers 2.8 mph. Three
spacers
3.0 mph. Fourspacers 3.2 mph.
Fig.
5
The lower half of the pulley iskeyed to the driven
shaft in the transmission. Fig.
6.
After the groundspeed has been selected, assem-
ble the top half of the pulley onto the shaft. Fig.
7.
Fig. 7
Slide the pulley down making sure the two halves
are assembled correctly. Fig. 8.
Fig. 6
Fig. 8
Placethe extraspacers on top of thepulley,assem-
ble the washer and nut. Tighten the nut. Fig.
9.
Fig. 9
20-2 SERVICE BULLETIN REFERENCES
OCTOBER
1984

Movethe idler brackettoapply tension on belt and
tighten idlerbracketnut.Fig. 10-A. Beltshould
deflectapproximately3/8”withfirmfinger
pressure. Fig. 10-B.Rotate engineseveral times to
seat belt ingrooves. Recheck belt tension andad-
just as necessary.
To replacethebelt, remove thepulley cover.
Loosen the nut on the idler pulley bracket which
will release tensionon thebelt.Fig. 12.
At this time, the belt can be rolled off the driven
pulley, or you can separate the pulleytoremove it.
Fig. 10-A Fig. 10-B
BELTREPLACEMENTPROCEDURES
A special beltis used todrive the transmission.It
was specially designed and manufactured foruse
only on this mower.
NOTE:
Useonly the belt available fromLawn-Boy No other
belt will function properly on this mower.
SAFETY WARNING:
Disconnectthe sparkplug lead.
Fig. 12
It isnecessary to remove the engine when replac-
ing the belt.
Remove the blade nut, blade and collar. Remove
three screws securing muffler and crankshaft sup-
port. Remove muffler.Fig. 13.
Fig. 13
Fig. 11
SERVICE BULLETIN REFERENCES.. 20-3
OCTOBER 1984

Removethefourboltsthatretainthe engine totheInstall a new exhaustgasket.Fig. 16.
muffler plate. Fig. 14.
NOTE:
Hold theengine while removing these bolts.Don’t
let it drop.
Fig. 16
Place the new belt over the drive pulley andset
engine back onto the muffler plate. Fig. 17.
Fig. 14Don’t disturbthe newexhaust gasketwhen putting
Lift the engine up and remove the old belt.
Also
remove the old exhaust gasket and dispose of it.
the engine in place.
Fig. 17
Fig. 15

Block one sideofmower up. Fig. 18. Clean the
threads of theengine mounting bolts withLOCQuic
Primer, Part #384884. Apply OMC Ultra Lock, Part
#388517 to thethreads of the bolts andassemble
all four into the engine mounting holes.
Clean the threads ofthethree mufflerscrews with
LOCQuic Primer, Part #385884. Apply OMC Ultra
Lock, Part #388517 to the threads.
Assemble the muffler, crankshaft support (flange
down) and start the three screws.
Fig. 18 Fig. 20
Tighten allfour engine mounting bolts to150-190
in.Ibs. (11-15 ft. Ibs.) Slide crankshaft supportgauge, Part #609968 over
the crankshaft with the thin wall of gauge going
between the support and crankshaft. Fig. 21.
Fig. 19
Fig. 21
SERVICE BULLETIN REFERENCES 20-5
OCTOBER 1984

Tighten all three screws to 142-170in. Ibs.,12-14
ft. Ibs. Fig. 22.
Fig. 22
Assemble the collar, bladeand nut ontocrankshaft.
Tighten blade nut to 45-50 ft. Ibs.
NOTE:
If the blade nut has been on and off four times it
should be replaced.
If not replaced, apply OMC
Ultra Lock tothreads of crankshaft before install-
ingnut.
SAFETY WARNING:
Check the torque of all fasteners under the deck.
fortightness.Aloosefastenercanbecomea
.thrown object.
Assemble thebeltonthe drivepulleyofthe
cranksha’ft. With the idler pulley bracketloose, the
belt should assemble over the driven pulley very
easily.Fig. 24.
Fig. 24
Movethe idler pulleystoapply tension on belt.Cor-
rect tension willbe approximately3/8” deflection
withfirm finger pressure. Fig. 25. Rotateengine
several times toseat beltingrooves. Recheck belt
tension and adjust as necessary.
After completing the belt replacement,start and
runthemower to checkoperation of the drive
system.
Fig. 25
Fig. 23
20-6 SERVICE BULLETIN REFERENCES
OCTOBER 1984

Fig. 27
Fig. 29
BULLETIN REFERENCES 20.7
OCTOBER 1984

To prevent dirt from entering insideof the wheel,
apply Lawn-Boy “A” grease in the groove of the
wheel cover. Fig. 30.
The transmissionassemblyisfilledwith “A”
grease at thefactory and should notrequire addi-
tional lubrication. However,
if seepageof the lubri-
cant is noted coming fromaround the seals
or from
the transmission housing gasketarea (Fig. 32-A),
greasecanbeaddedthroughthe zerk fitting
located on, the lower sideof the transmission. Fig.
32-6.
Fig. 30
Every
50 hours of operation the rear wheel bolts
should be lubricated. Removeand clean the wheel
bolt, liberallyoil the bearing and each felt washer
andreassemble.Fig. 31.
Fig. 32-A Fig.32-6
Should itbe necessaryto add lubricanttotransmis-
sion, watch for an
upward movement ofthe clutch
armwhen putting greasein.Whenmovement
is
noted,stoptheflowoflubricantimmediately.
Fig. 33.
NOTE:
Do not put an excessive amount in transmission
because there is a possibilityof a pressure build-
upresulting inseal failures.
Fig. 33
20-8 ................................................................................................................................................................... SERVICE BULLETIN REFERENCES
OCTOBER
1984

FRONT WHEEL MAINTENANCE
It is not necessary to lubricatethefront wheel
bolts.
For engine,exhaustandbladeservicingrefer
to
their respective sections in the Manual.
TRANSMISSIONSERVICING AND REPAIR
WARNING:
Disconnect the spark plug lead.
Remove the hairpinretainers and detach the han-
dle from the brackets. Lay the handle down over
front
of mower. Fig. 34.
Remove thedrivenpulleyassemblyfrom the
transmission. Fig. 36.
Fig. 36
Removethe 7/16” nut from long transmission bolt
thatretainstheclutch cablebracketandspring
assembly totransmission. Lift thebracket, springs
andarmassembly offtransmission. Lay to one
side.
Fig. 34
Remove two screws and lift cover off. Fig. 35.
Fig. 37
.Fig.35
SERVICE BULLETIN REFERENCES 20-9
OCTOBER 1984

An “0” ring is preassembled on thehubofthe
clutch arm before final assembly.When removing
the arm from the transmission, the
“0” ring slides
off into the holeand around thesquare shaft of the
shift fork. It willhave to be removed from the hole.
Fig. 38.
Remove the rightrear wheelbolt with a314” socket.
Fig. 38
To free the transmission from the housing,remove
the shoulder bolt and nut.Fig.
39.
Fig. 39
Fig. 40
Using a pair of expansion pliers,removethe retain-
ing ring from end of shaft. Fig. 41.
Fig.
41