Toro 78231 User manual

Operator’s Manual
IMPORTANT: Read this manual carefully. It contains information about your
safety and the safety of others. Also become familiar with the controls and
their proper use before you operate the product.
FORM NO. 3319–559 Rev A
Wheel Horse
42” Mower
for
Lawn and Garden Tractors
Model No. 78231 – 8900001 & Up

Printed in USA
Introduction
We want you to be completely satisfied with your new
product, so feel free to contact your local Authorized
Service Dealer for help with service, genuine replacement
parts, or other information you may require.
Whenever you contact your Authorized Service Dealer or
the factory, always know the model and serial numbers of
your product. These numbers will help the Service Dealer
or Service Representative provide exact information about
your specific product. You will find the model and serial
number plate located in a unique place on the product as
shown below.
1
1275
1. Modeland Serial Number Plate
For your convenience, write the product model and serial
numbers in the space below.
Model No:
Serial No.
The warning system in this manual identifies potential
hazards and has special safety messages that help you and
others avoid personal injury, even death. DANGER,
WARNING and CAUTION are signal words used to
identify the level of hazard. However, regardless of the
hazard, be extremely careful.
DANGER signals an extreme hazard that will cause
serious injury or death if the recommended precautions
are not followed.
WARNING signals a hazard that may cause serious injury
or death if the recommended precautions are not followed.
CAUTION signals a hazard that may cause minor or
moderate injury if the recommended precautions are not
followed.
Two other words are also used to highlight information.
“Important” calls attention to special mechanical
information and “Note” emphasizes general information
worthy of special attention.
The left and right side of the machine is determined by
sitting on the seat in the normal operator’s position.

1
Contents
Page
Safety and Instruction Decals 2. . . . . . . . . . . . . . . . . .
Assembly 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loose Parts 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing Discharge Chute 4. . . . . . . . . . . . . . . . . .
Install Rear and Adjustable Links 5. . . . . . . . . . . .
Installing the Mower 5. . . . . . . . . . . . . . . . . . . . . .
Transport Height Adjustment 6. . . . . . . . . . . . . . .
Side-to-Side Mower Leveling 7. . . . . . . . . . . . . . .
Front-to-Rear Blade Slope 8. . . . . . . . . . . . . . . . . .
Removing the Mower 9. . . . . . . . . . . . . . . . . . . . .
Operation 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Side Discharge 10. . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating the Power Take Off (PTO) 10. . . . . . . . .
Page
Attachment Lift Lever 11. . . . . . . . . . . . . . . . . . . . .
Attachment Power Lift 11. . . . . . . . . . . . . . . . . . . . .
Adjusting Dial-A-Height 12. . . . . . . . . . . . . . . . . . .
Adjusting Anti-Scalp Rollers 12. . . . . . . . . . . . . . . .
Tips for Mowing Grass 13. . . . . . . . . . . . . . . . . . . .
Maintenance 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Interval Chart 14. . . . . . . . . . . . . . . . . . . . .
Cutting Blade 15. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Greasing and Lubrication 17. . . . . . . . . . . . . . . . . . .
Blade Drive Belt 17. . . . . . . . . . . . . . . . . . . . . . . . .
Storage 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety
2
Safety and Instruction Decals
Safety decals and instructions are easily visible to the operator and are located near any
area of potential danger. Replace any decal that is damaged or lost.
ON GRASS DEFLECTOR
(Part No. 93–1122)
ON MOWER RIGHT SIDE
(Part No. 116286)
ON MOWER LEFT AND
RIGHT SIDES
(Part No. 92–7108)

3
Assembly
Loose Parts
Note: Use the chart below to identify parts used for assembly.
DESCRIPTION QTY. USE
Grass deflector
Torsion spring
Washer (1/2”)
Cotter pin (3/4”)
Plastic washer
Rubber bushing
Jam nut (3/8”–16)
1
1
1
1
2
1
1
Install grass deflector
Rear link
Washer (1/2”)
Cotter pin (1”)
Hairpin cotter (2–9/16”)
1
2
1
2
Install rear link
Adjustable link
Washer (1/2”)
Cotter pin (1”)
Hairpin cotter (2–9/16”)
1
2
1
1
Install front link to mower
V belt
Hairpin cotter (3–3/8”)
Washer (3/4”)
1
2
2Install mower to tractor
Operator’s Manual 1Read before operating

Assembly
4
Installing Grass Deflector
1. Locate items shown in Fig. 1.
2. Place the short end of the spring into the small hole in
the grass deflector.
3. Position spring and grass deflector over post on rear of
deck and secure with 1/2” washer and 3/4” cotter pin
(Fig. 1).
4. Slide rubber bushing and plastic washer over stud at
front of mower.
5. Place grass deflector over stud and secure with second
plastic washer and 3/8” jam nut (Fig. 1).
1
3
2
5
4
6m-3141
7
Figure 1
1. Grass deflector
2. Spring
3. Cotter pin 3/4”
4. Washer 1/2”
5. Rubber bushing
6. Plastic washer
7. Jam nut 3/8”
Important Grass deflector must be spring loaded in
the down position. Lift chute up to test that it snaps to the
full down position.
POTENTIAL HAZARD
•Without the grass deflector, discharge cover, or
complete grass catcher assembly mounted in
place, you and others are exposed to blade
contact and thrown debris.
WHAT CAN HAPPEN
•Contact with rotating mower blade(s) and
thrown debris will cause injury or death.
HOW TO AVOID THE HAZARD
•NEVER remove the grass deflector from the
mower because the grass deflector routes
material down toward the turf. If the grass
deflector is ever damaged, replace it
immediately.
•Never put your hands or feet under the mower.
•Never try to clear discharge area or mower
blades unless you move the power take off
(PTO) to “OFF” and rotate the ignition key to
“OFF.” Also remove the key and pull the wire
off the spark plug(s).

Assembly
5
Installing the Rear and
Adjustable Links
1. Install a hairpin cotter (2–9/16 in.) into the inside hole
of the rear link (Fig. 2).
2. Install the rear link into the gage wheel support and
secure with a washer (1/2 in.) and cotter pin (1 in.)
(Fig. 2).
3. Install rear link into the attachment lift and secure with
a washer (1/2 in.) and hairpin cotter (2–9/16 in.)
(Fig. 2).
1
2
3
4
5
m-5812
5
67
Figure 2
1. Rear link
2. Washer, 1/2 in.
3. Cotter pin, 1 in.
4. Attachment lift
5. Hairpin cotter, 2–9/16 in.
6. Inside hole
7. Gage wheel support
4. Install front adjustable link to the attachment lift with
a washer (1/2 in.) and hairpin cotter (2–9/16 in.)
(Fig. 3).
5. Install front adjustable link to the mower with a
washer (1/2 in.) and hairpin cotter (2–9/16 in.) (Fig. 3).
m–3165
1
2
3
4
5
Figure 3
1. Front adjustable link
2. Washer 1/2”
3. Cotter pin 1”
4. Attachment lift
5. Hairpin cotter 2–9/16”
Installing the Mower
1. Park the tractor on a flat surface, disengage the power
take off (PTO), set the parking brake, and turn the
ignition key to “OFF” to stop the engine. Remove the
key.
2. Turn the front wheels fully to the left and raise
attachment lift lever all the way to the latched
position; refer to tractor Operator’s Manual.
3. Slide the mower under the chassis from the right side
(Fig. 4) and align rear mounting bushings with ends of
lift arms.
4. Straighten the front wheels, turn Dial-A-Height knob
counterclockwise, all the way, and lower the
attachment lift lever to the mounting position; refer to
tractor Operator’s Manual.
5. Place rear guide bushings, first left side then right,
onto lift arms then slide deck left into position (Fig. 4).
6. Secure deck to rear lift arms with 3/4” washers and
3–3/8” hairpin cotters (Fig. 4).

Assembly
6
14
2
3
5
1234a
Figure 4
1. Lift arm
2. Washer 3/4”
3. Hair pin cotter 3–3/8”
4. Rear link
5. Attachment lift
7. Attach rear link to attachment lift with 1/2” washer
and 2–9/16” hairpin cotter (Fig. 3 & 4).
8. Install front adjustable link to right front lift arm with
1/2” washer and 2–9/16” hairpin cotter (Fig. 5).
m–3536
12
3
Figure 5
1. Adjustablelink
2. Washer 1/2” 3. Hairpin cotter 2/916”
9. Pull on idler pulley to relax belt tension and install
mower drive belt into the top, or single engine drive
pulley groove (Fig. 6).
21
Figure 6
Top View
1. Mowerbelt 2. Engine pulley
Note: Ensure that the belt is properly located in the
engine, mower, and idler pulleys.
10.Check mower level; refer to Side-to-Side Mower
Leveling, page 7 and Front-to-Rear Blade Slope,
page 8.
11. Raise attachment lift lever all the way to the latched
position and adjust mower height-of-cut (refer to page
13) and transport height adjustment (refer to page 7).

Assembly
7
Transport Height Adjustment
Transport height is set at the factory and should not need
adjustment; however if the belt covers contact the footrest
in the raised position, adjustment is required.
1. Adjust by turning transport height nut, (Fig. 7) on lift
mechanism, clockwise to raise or counterclockwise to
lower mower.
2. Adjust nut until there is 1/16–1/8 ” clearance between
belt cover and left footrest.
1223
1
Figure 7
1. Nut
Side-to-Side Mower Leveling
The mower blades must be level from side to side. Check
the side-to-side level any time you install the mower or
when you see an uneven cut on your lawn. Before you
level the mower, set the air pressure in the front and rear
tires to 12 psi (.85 kPa).
2-3/4” to 4” Height-of-Cut Range
When the mower height-of-cut is set to the 2-3/4” to 4”
range the mower is suspended from the tractor.
1. Park the tractor on a flat surface, disengage the power
take off (PTO), set the parking brake, and turn the
ignition key to “OFF” to stop the engine. Remove the
key.
2. Raise attachment lift lever all the way to the latched
position.
3. Carefully rotate blade(s) side to side (Fig. 8). Measure
between the outside cutting edges and the flat surface
(Fig. 8). If both measurements are not within 3/16”, an
adjustment is required; refer to steps 4 and 6.
Front
1
2
3
3
2
Figure 8
1. Blades side to side
2. Outside cutting edges 3. Measure here
4. Loosen adjustment bolt on one side and rotate hanger
bracket to raise or lower mower (Fig. 9).
5. After adjusting, tighten bolt and check side-to-side
level.
Important If hanger is rotated to the end of
adjustment on one side and mower is not level, adjust the
opposite side.

Assembly
8
1
2
1224
Figure 9
1. Bolt 2. Hangerbracket
6. Now check the front-to-rear blade slope; refer to
Front-to-Rear Blade Slope, page 8.
3/4” to 2-3/4” Height-of-Cut Range
When the mower height-of-cut is set to the 3/4” to 2-3/4”
range the rear gage wheels contact the ground. There is no
side-to-side adjustment for this height range, see
Front-to-Rear Blade Slope.
Front-to-Rear Blade Slope
Check the front-to-rear blade slope any time you install
the mower. Before checking the slope, set air pressure in
the front and rear tires to 12 psi (.85 kPa). If the front
blade tip is not 0–3/8” (0–9.5 mm) lower than the rear
blade tip, adjust the blade slope using the following
instructions:
1. Park the tractor on a flat surface, disengage the power
take off (PTO), set the parking brake, and turn the
ignition key to “OFF” to stop the engine. Remove the
key.
2. Check and adjust side-to-side blade level if you have
not checked the setting; refer to Side-to-Side Mower
Leveling, page 7.
3. Adjust the Dial-A-Height knob so the height-of-cut is
in the middle of the range and lower attachment lift.
4. Carefully rotate blades so they are facing front and
rear (Fig. 10).
5. Measure between the tip of the front blade (Fig. 10)
and the tip of the rear blade to the flat surface. If the
front blade tip is not 0–3/8” (0–9.5 mm) lower than the
rear blade tip adjust front adjustment link.
Front 1078
1
2
3
4
4
Figure 10
1. Bladefront to rear
2. Measure front blade tip 3. Measure rear blade tip 4. Measure here
6. To adjust front-to rear blade level loosen jam nut on
front adjustable link. (Fig. 11).
7. Rotate the bolt on front adjustable link to change
front-to rear blade level (Fig. 11).
Note: To raise the front of the mower, shorten the
adjustable link by turning bolt clockwise.