SERVICE MANUAL
LECTRICAL TROUBLESHOOTING
E
VOLUME 1
ALL MODELS WITH MODULAR WIRING
SERIAL NUMBERS 310000 THROUGH 469999
THE GRASSHOPPER COMPANY
Moundridge, Kansas 67107 U.S.A.
PHONE (620) 345-8621
FAX (620) 345-2301
PRICE $12.00
Form 172110
Printed in U.S.A.
Rev. 01-95
INTRODUCTION
This manual has been developed to diagnose component failures only. It will not
indicate a problem in the wiring or terminals.
For example, if the troubleshooting guide
indicates that the left steering switch is
defective and replacing the left steering
switch does not solve the problem; then you
may have bad terminals or wiring to that
switch.
Consult the operator's manual wiring diagram for the specific year and model of the
machine you are working on for troubleshooting. For further assistance, contact
The Grasshopper Company, service department, at (620) 345 - 8621.
Copyright © 1995, 1994, 1990 by The Grasshopper Company. The following material is proprietary information. All rights reserved.
Reproduction or dissemination in any form by any means is prohibited, except by express written permission from The Grasshopper
Company.
2
TABLE OF CONTENTS
PAGE
INTRODUCTION 2
SYMBOLS USED ON WIRING DIAGRAMS 5
SWITCH FUNCTIONS 6-7
TROUBLESHOOTING CONTROL RELAYS
Model 720, 721, and 725 ........................................................................................... 8
Model 718D and 721D............................................................................................... 8
Control relay - Model 720, 718D, 721, 721D, and 725 .............................................. 9
Circuit board diode problems - Model 720, 718D, 721, 721D, and 725..................... 9
FUSE BLOCK DIAGRAMS 10
TESTING SAFETY SYSTEM FOR PROPER OPERATION
Model 612, 614, 616, 718, 718K and 720K ............................................................. 11
Model 720 (Onan), 718D, 721D, 721 and 725 ........................................................ 12
BATTERY CHARGING SYSTEM
Model 718 (Briggs & Stratton Twin-II engine) .......................................................... 13
Model 612, 614, 616, and 718 (Briggs & Stratton Vanguard engines) and
Model 718K and 720K (Kohler Magnum & Command engines) .............................. 14
Model 720 (Onan engine) ........................................................................................ 15
Model 718D, 721, 721D, and 725 (All Kubota engines) .......................................... 16
ENGINE WILL NOT CRANK
Model 612, 614, and 616 (Briggs & Stratton engines)........................................ 18-19
Model 718 (Briggs & Stratton Vanguard engines) .............................................. 20-21
Model 718K (Kohler Magnum engine) ................................................................ 22-23
Model 718K and 720K (Kohler Command engines) ........................................... 24-25
Model 720 (Onan engine) ................................................................................... 26-27
Model 718D, 721, 721D, and 725 (All Kubota engines) ..................................... 28-29
ENGINE WILL CRANK, BUT NOT START
Model 612, 614, 616, 718, 718K, and 720K (All engines) ....................................... 30
Model 720 (Onan engine) ........................................................................................ 31
Model 721 and 725 (Kubota gasoline engines) ....................................................... 32
Model 718D and 721D (Kubota diesel engines) ...................................................... 33
ENGINE STARTS, BUT DIES
WHEN LEVERS ARE BROUGHT IN OR PTO SWITCH IS ENGAGED
Model 612, 614, 616 and 718 .................................................................................. 34
Model 718K and 720K ............................................................................................. 35
Model 720 (Onan engine) ........................................................................................ 36
Model 718D, 721, 721D, and 725 (All Kubota engines) .......................................... 37
(continued)
3
TABLE OF CONTENTS
ENGINE STARTS, BUT DIES
WHEN KEY SWITCH IS RELEASED
Model 718D and 721D (Kubota diesel engines) ................................................. 38-39
TROUBLESHOOTING PTO CLUTCH
Model 612, 614, 616, 718, 718K and 720K ............................................................. 40
Model 718D, 720, 721, 721D and 725..................................................................... 41
1994 MODEL UPDATES 42-44
4
SYMBOLS USED ON WIRING DIAGRAMS
Indicates a ground point.
Indicates wires crossover but are not
connected.
Symbol indicating wires are connected.
Symbol for a diode. The arrow indicates
the direction of current flow. Current will
not flow in the other direction if the diode
is working properly.
0 0
Symbol for glass type fuse.
Symbol for automotive type fuse. The
number in the center of the fuse indicates
the amperage rating of the fuse.
Indicates wires are spliced.
5
M
R
A
SWITCH FUNCTIONS
Ignition switch, part no. 183806.
(Models 612, 614, 718, 718K, and 720K).
S
L
GB
B
S
I
M Magneto terminal.
S Starter terminal.
B Battery terminal.
L Lights, accessory terminal.
G Ground terminal.
Ignition switch, part no. 183830.
(Model 720).
R Regulator terminal.
A (Not used).
B Battery terminal.
S Starter terminal.
I Ignition terminal.
NC NO
NC NO
50
19
17
AC
30
RELEASED
DEPRESSED
Ignition switch, part no. 183825.
(Models 718D, 721, 721D, and 725).
30 Battery terminal.
50 Starter terminal.
AC Accessory terminal.
17 Glow plug terminal (Diesel only).
19 Glow plug indicator terminal (Diesel only).
Brake switch, part no. 183894.
NC (normally closed) - means that the
contact is closed and current will flow
between these two terminals. When
the button is depressed, these two
terminals become open.
NO (normally open) - means that the
contact is open with the switch
mechanism released. When the
button is depressed, these two terminals become closed.
The dotted line indicates an electrical connection between the two terminal posts.
6
COMMON
SWITCH FUNCTIONS
Left and right steering switch, part no. 183860.
NC (normally closed) - means that the
contact is closed with the switch
mechanism released. The contact
NC
NO
position is reversed when the switch
lever is depressed.
RELEASED
COMMON
DEPRESSED
TOGGLE SWITCH POSITION
ON
OFF
ON
OFF
NC
NO
NO (normally open) - means that the
contact is open with the switch
mechanism released. The contact
position is reversed when the switch
lever is depressed.
The dotted line indicates an electrical connection between the two terminal posts.
PTO switch, part no. 184082.
The dotted line indicates an electrical connection between the two terminal posts.
PTO switch, part no. 183925.
The dotted line indicates an electrical connection between the two terminal posts.
RELEASED
DEPRESSED
Seat switch, part no. 183870.
The dotted line indicates an electrical connection between the two terminal posts.
7
TROUBLESHOOTING CONTROL RELAYS
MODELS 720, 721, AND 725.
1. Control relay - inspection.
A. Control relay A has 2 red wires, 1
black wire, and 1 yellow wire in the
relay socket.
B. Control relay B has 3 blue wires and
1 yellow wire in the relay socket.
2. Assuming the main fuse, PTO fuse,
ignition fuse are good, failure of control
relay A or associated wiring will be
evidenced by the following three symptoms:
A. PTO clutch will not engage.
B. Hourmeter will not run.
C. Ignition coil will not have any volt-
age on the positive terminal.
3. Assuming the start fuse is good, failure
of control relay B or associated wiring
will result in starter solenoid not engaging; thus the starter motor will not
operate.
MODELS 718D AND 721D.
1. Control relay - inspection.
A. Control relay A has 2 red wires, 1
black wire, and 1 yellow wire in the
relay socket.
B. Control relay B has 3 blue wires and
1 yellow wire in the relay socket.
2. Assuming the main fuse, PTO fuse,
ignition fuse are good, failure of control
relay A or associated wiring will be
evidenced by the following three symptoms:
A. PTO clutch will not engage.
B. Hourmeter will not run.
C. Fuel solenoid will pull in but not
hold.
3. Assuming the start fuse is good, failure
of control relay B or associated wiring
will result in starter solenoid not engaging; thus the starter motor will not
operate.
To main
fuse
To pad
M of PC
board
To PTO
fuse &
ignition
fuse
To pad
A of PC
board
This wire goes to ground when:
1. Driver on sea t and park ing brake relea sed,
2. or PTO off, both steering levers out,
Red
+12 volts
with key
switch in
'RUN '
position
Bla ck
3. or both of the above.
A
+12 volts when relay
'A' is energized
Red
Yellow
+12 volts with key
sw it ch in 'S T ART '
position
Figure 1
B
Blue
This w ire goes to
ground with steering
levers out and PTO off
Yellow
+12 volts when relay
'B' is e ne r g i ze d
Blue
Blue
To sta rt
fuse
To pad
R of PC
board
Sta rter
solenoid
To sta rt
fuse
8
Control Relay - Model 720, 718D, 721,
721D, and 725
Circuit Board Diode Problems - Model
720, 718D, 721, 721D, and 725
Assuming a normal diode on the circuit,
board, relay B is affected by a problem in
the circuit containing the PTO switch, and
left and right steering switches.
Assuming a normal diode on the circuit
board, relay A is affected by a problem in
the circuit containing the PTO switch, and
left and right steering switches. It is also
affected by a problem in the circuit containing the parking brake switch and seat
switch.
R
Refer to the illustration below to locate the
diode on the circuit board between pad R
and A.
Open Diode
An open diode will result in the following
symptoms:
Assuming steering levers out and PTO
switch off, engine can be cranked and
started only with driver on the seat and
the parking brake in the 'OFF' position.
If driver gets off of the seat or puts parking brake to the 'ON' position, the engine
will die.
Shorted Diode
Assuming an operator on the seat and
parking brake is 'OFF', engine can be
cranked and started with PTO switch in
the 'ON' position or steering levers in.
Figure 2
A
9
FUSE BLOCK DIAGRAMS
E
A
C
G
30
REG.
7.5
START
7.5
PTO
7.5
LIGHT
Figure 3
D
B
H
MODELS 612, 614, 616, 718,
718K, and 720K.
The dotted line indicates an electrical
F
connection between the two terminal
posts.
H
B
A
15
MAIN
30
REG.
C
D
MODELS 718D, 720, 721, 721D, 725.
F
E
7.5
PTO
The dotted line indicates an electrical
connection between the two terminal
posts.
G
7.5
30
J
IGN. START
I
Figure 4
10
TESTING SAFETY SYSTEM FOR PROPER OPERATION
Steering levers
out, PTO switch
'OFF', and
operator 'ON'
seat. If engine
starts, all switches
are functioning in
their closed
position.
Turn engine
'OFF'.
Does engine
crank with
operator 'OFF'
the seat?
No
Does engine
crank with
operator 'ON'
the seat and
only left steering
lever 'IN'?
No
Does engine
crank with only
right steering
lever 'IN'?
No
Does engine
crank with only
the PTO switch
turned 'ON'?
No
Steering levers
out, PTO switch
'OFF', operator
'OFF' seat,
parking brake
'OFF' and engine
running. Does
engine die when
steering levers
are pulled in?
No
Replace interlock
module.
MODEL612, 614, 616, 718,
718K, 720K
Yes
Yes
Yes
Yes
Yes
Replace seat
switch.
Adjust or
replace left
steering switch.
Adjust or
replace right
steering switch.
Replace PTO
switch.
Steering levers
out, PTO switch
'OFF', operator
'ON' seat,
parking brake '
ON' and engine
running. Does
engine die when
steering levers
are pulled in?
No
Replace brake
switch.
Yes
Notes:
Proper operation of the safety
system indicates that:
1. To start the engine, the operator
must be on the seat, both steering
levers must be out, and the PTO
switch must be off.
2. With the engine running and the
operator off the seat, the engine will die if either steering
lever is brought in or the PTO
switch is turned on.
3. The engine will also die if the
operator gets off the seat with
either steering lever in or the
PTO switch turned on.
4. The engine will die if the steering levers are brought in with
the parking brake on.
All safety
systems are
functioning
properly.
11
Steering levers
out, PTO switch
'OFF', parking
brake 'OFF',
operator 'OFF'
seat and engine
running.
TESTING SAFETY SYSTEM FOR PROPER OPERATION
MODEL 720(Onan), 718D, 721D,
721 and 725
Notes:
Proper operation of the safety
system indicates that:
1. To start the engine, both steering
levers must be out, and the PTO
switch must be off. The engine
will start with the operator on or
off the seat and the parking
brake either on or off.
2. With the engine running and the
operator off the seat, the engine will die if either steering
lever is brought in or the PTO
switch is turned on.
3. The engine will also die if the
operator gets off the seat with
either steering lever in or the
PTO switch turned on.
4. The engine will die if the steering levers are brought in with
the parking brake on.
Does engine die
when left
steering lever is
brought 'IN'?
No
Adjust or
replace left
steering switch.
Does engine die
Yes
when right
steering lever is
brought 'IN'?
No
Adjust or
replace right
steering switch.
Yes
Does engine die
when the PTO
switch turned
'ON'?
No
Replace PTO
switch.
Yes
out, PTO switch
'ON' and engine
engine die when
Steering levers
'OFF', operator
'ON' seat,
parking brake
running. Does
steering levers
are brought in?
No
Replace brake
switch.
Yes
Does engine die
raises up off the
Steering levers
in, PTO switch
'OFF', operator
'ON' seat,
parking brake
'OFF' and
engine running.
when operator
seat?
No
Replace seat
switch.
All safety
systems are
functioning
properly.
Yes
12
BATTERY CHARGING SYSTEM
Engine is not
running.
Attach voltmeter
to negative and
positive posts of
battery.
Does voltmeter
read 12.2 volts
or above?
No
Test and
recharge battery.
Start engine and
observe battery
voltage at full
throttle.
Is voltage at
battery between
13 and 14.7
volts?
No
Unplug diode
wire at engine.
MODEL 718
(Briggs & Stratton Twin-II engine)
Yes
Yes
Battery is in
good condition.
Charging system
is functioning
properly.
Check for
shorted wires.
Notes:
1. Voltage tests are performed
with a DC/AC voltmeter.
2. Tests are performed after
regulator fuse is checked.
3. AC voltage tests are performed
with engine at 3600 rpm.
Using AC
voltmeter
measure AC
voltage output
from engine
connector to
ground.
Does AC voltage
measure 28
volts* or more at
full throttle?
No
Service stator.
Yes
Check for
continuity of
in-line diode
wire.**
*voltage may vary depending upon RPM.
**a properly functioning diode will show continuity in one
direction only. If the diode does not show continuity in either
direction, diode is open. Replace diode wire. If diode shows
continuity in both directions it is shorted. Replace diode wire.
(see operator's manual for the correct part number.)
13
BATTERY CHARGING SYSTEM
Engine is not
running.
Attach voltmeter
to negative and
positive posts of
battery.
Does voltmeter
read 12.2 volts
or above?
No
Test and
recharge battery.
Start engine and
observe battery
voltage at full
throttle.
Is voltage at
battery between
13 and 14.7
volts?
No
Disconnect
regulator-rectifier
plug. Place AC
voltmeter across
AC terminals in
plug and read
voltage.
MODEL 612, 614, 616, and 718
(Briggs & Stratton Vanguard
engines)
MODEL 718K and 720K
(Kohler Magnum & Command
engines)
Yes
Yes
Battery is in
good condition.
Charging system
is functioning
properly.
Check for
shorted wires.
Notes:
1. Voltage tests are performed
with a DC/AC voltmeter.
2. Tests are performed after
regulator fuse is checked.
3. AC voltage tests are performed
with engine at 3600 rpm.
Does voltage
read less than
28 volts AC with
engine running?
No
If AC voltage
measures more
than 28 volts
replace regulator-
rectifier.
For more
detailed testing
consult the
engine repair
manual.
Yes
Service stator.
14
BATTERY CHARGING SYSTEM
Engine is not
running.
Attach voltmeter
to negative and
positive posts of
battery.
Does voltmeter
read 12.2 volts
or above?
No
Test and
recharge battery.
Start engine and
observe battery
voltage at full
throttle.
Is voltage at
battery between
13 and 14.7
volts?
No
Disconnect
regulator-rectifier
plug. Place AC
voltmeter across
AC terminals in
plug and read
voltage.
MODEL 720
(Onan engine)
Yes
Yes
Battery is in
good condition.
Charging system
is functioning
properly.
Notes:
1. Voltage tests are performed
with a DC/AC voltmeter.
2. Tests are performed after
regulator fuse is checked.
3. AC voltage tests are performed
with engine at 3600 rpm.
Check for
shorted wires.
Does voltage
read less than
41 volts AC at
3600 rpm?
No
Replace
regulator-
rectifier.
For more
detailed testing
consult the
engine repair
manual.
Yes
Service stator.
15
BATTERY CHARGING SYSTEM
Engine is not
running.
Attach voltmeter
to negative and
positive posts of
battery.
Does voltmeter
read 12.2 volts
or above?
No
Test and
recharge battery.
Start engine and
observe battery
voltage at full
throttle.
Is voltage at
battery between
13 and 14.7 volts?
No
AC
Does
appear between
the 2 blue wires
from alternator?
A. 10 volts* AC
B. 36 volts* AC
voltage
at idle?
at full throttle?
No
Replace
alternator.
MODEL 718D, 721, 721D, 725
(All Kubota engines)
Yes
Yes
Yes
Battery is in
good condition.
Charging system
is functioning
properly.
Does voltage
appear on white
wire of voltage
regulator?
No
Yes
Does green wire
plug between the
shorted wires.
on the regulator
battery positive?
Check for
two blue wires
show ground
when tested
Check ground
connection.
to
No
Notes:
1. Voltage tests are performed
with a DC/AC voltmeter.
2. Tests are performed after
regulator fuse is checked.
3. AC voltage tests are performed
with engine at 3600 rpm.
Yes
Is voltage at red
wire of voltage
regulator 13-14
Replace voltage
volts?
No
regulator.
Yes
Check red wire
from terminal 30
of ignition switch
and terminals
to voltage
regulator.
Does voltage
appear on
terminal AC of
ignition switch?
No
Check ignition
switch for
continuity from
terminal AC to
terminal 30.
*voltage may vary + or - 3 volts.
Yes
Check white wire
rom terminal AC
of ignition switch
and terminals
to voltage
regulator.
16
This page is intentionally left blank.
17
ENGINE WILL NOT CRANK
E
Test battery for
condition and
charge.
OK
Steering levers
out, PTO switch
'OFF', operator
on seat.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
terminal 'C' of
start fuse?
No
Problem is the
key switch or
the power to the
key switch.
MODEL 612, 614 and 616.
(Briggs & Stratton engines)
Yes
Does voltage
appear from
terminal 'D' of
start fuse?
No
Replace start
fuse.
If there is voltage
Yes
at terminal D of
start fuse, there
should also be
voltage on blue
wire at starter
solenoid.
A
continues on
next page
NOTES:
1. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 40 on page 42.
AB
30
REG.
C
7.5
7.5
D
F
START
E
PTO
KEY
SWITCH
IN START POSITION
BU
START FUSE
M
BSG
RD
+
-
BU
L
STARTER
SOLENOID
LEFT
STEER
STEERI NG LEVERS OUT
LT
STR
YE
RIGHT
STEER
YE
STR
Figure 5
18
RT
PTO
SWITCH
PTO OFF
YE
SEAT
SWITCH
DRIVER
ON SEAT
YE
SEAT
G
7.5
LIGHT
H
Figure 6
BRAKE
SWITCH
GR
NONC
YE
DIODE ALLOWS ENGIN
TO CRANK WITH BRAKE
SWITCH ON OR OFF
continued
A
ENGINE WILL NOT CRANK
MODEL 612, 614 and 616.
(Briggs & Stratton engines)
VOLT METER
Key switch is
now OFF.
You
are now testing
a ground circuit.
All tests will be
to the battery
positive (hot)
side.
Does the yellow
wire at starter
solenoid show
ground when
tested? Refer
to figure 7.
No
Does seat switch
show ground on
both yellow
wires? (Note:
Wires must be
installed on
switch and seat
switch must be
activated.)
No
Replace seat
switch.
Yes
Check starter
Problem could be
starter solenoid or
Yes
Do both wires
on RT steering
switch show
ground when
Do either of the
RT steering
switch wires
show ground?
Replace PTO
solenoid.
starter.
tested?
No
No
switch.
Yes
Yes
Do both wires
on LT steering
switch show
ground when
tested?
No
LT steering
switch is bad or
out of
adjustment.
RT steering
switch is bad or
out of
adjustment.
BLACK LEAD
Yes
Recheck starter
solenoid or
starter.
RED LEAD
STARTER SOLENOID
BLUE
+
YELLOW
Figure 7
-
19
ENGINE WILL NOT CRANK
E
Test battery for
condition and
charge.
OK
Steering levers
out, PTO switch
'OFF', operator
on seat.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
terminal 'C' of
start fuse?
No
Problem is the
key switch or
the power to the
key switch.
MODEL 718.
(Briggs & Stratton Twin II
and Vanguard engines)
Does voltage
Yes
appear from
terminal 'D' of
start fuse?
No
Replace start
fuse.
Yes
If there is voltage
at terminal D of
start fuse, there
should also be
voltage on blue
wire at starter
solenoid.
A
continues on
next page
NOTES:
1. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 41 on page 42.
AB
30
REG.
C
7.5
7.5
D
F
START
E
PTO
KEY
SWITCH
IN START POSITION
BU BU
START FUSE
M
BSG
RD
+
-
G
7.5
LIGHT
H
Figure 9
RIGHT
STEER
STEERI NG LEVERS OUT
STARTER
SOLENOID
L
RT
STR
YE
YE
LEFT
STEER
LT
STR
PTO
SWITCH
PTO OFF
YE
SEAT
SWITCH
DRIVER
ON SEAT
YE
SEAT
YE
DIODE ALLOWS ENGIN
TO CRANK WITH BRAKE
SWITCH ON OR OFF
BRAKE
SWITCH
GR
NONC
Figure 8
20
continued
A
ENGINE WILL NOT CRANK
MODEL 718.
(Briggs & Stratton Twin II and Vanguard engines)
Key switch is
now OFF.
You
are now testing
a ground circuit.
All tests will be
to the battery
positive (hot)
side.
Does the yellow
wire at starter
solenoid show
ground when
tested? Refer to
figure 10.
No
Does seat switch
show ground on
both yellow
wires? (Note:
Wires must be
installed on
switch and seat
switch must be
activated.)
No
Replace seat
switch.
Yes
Problem could be
starter solenoid or
Yes
Do both wires
on LT steering
Do either of the
show ground?
Replace PTO
Check starter
solenoid.
starter.
switch show
ground when
tested?
No
LT steering
switch wires
No
switch.
Yes
Yes
VOLT METER
Do both wires
on RT steering
switch show
ground when
tested?
No
RT steering
switch is bad or
out of
adjustment.
LT steering
switch is bad or
out of
adjustment.
BLACK LEAD
Recheck starter
Yes
solenoid or
starter.
RED LEAD
STARTER SOLENOID
BLUE
+
YELLOW
Figure 10
-
21
ENGINE WILL NOT CRANK
T
Test battery for
condition and
charge.
OK
Steering levers
out, PTO switch
'OFF', operator
on seat.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
terminal 'C' of
start fuse?
No
Problem is the
key switch or
the power to the
key switch.
MODEL 718K.
(Kohler Magnum engines)
Does voltage
Yes
appear from
terminal 'D' of
start fuse?
No
Replace start
fuse.
Yes
If there is voltage
at terminal D of
start fuse, there
should also be
voltage on blue
wire at starter
solenoid.
A
continues on
next page
AB
30
REG.
C
7.5
7.5
D
F
START
E
PTO
G
7.5
LIGHT
H
Figure 12
PTO
SWITCH
YE
NONC
SWITCH
YE
SEAT
DRIVER
ON SEAT
SEAT
KEY
SWITCH
IN START POSITION PTO OFF
BU
RD
+
-
START FUSE
L
M
BSG
STARTER
SOLENOID
BU
BRAKE
SWITCH
YE
DIODE ALLOWS ENGINE
TO CRANK WITH BRAKE
SWITCH ON OR OFF
LEFT
STEER
STEERIN G LEVERS OU
LT
STR
YE
RIGHT
STEER
YE
RT
STR
GR
Figure 11
22
continued
A
ENGINE WILL NOT CRANK
MODEL 718K.
(Kohler Magnum engines)
Key switch is
now OFF.
You
are now testing
a ground circuit.
All tests will be
to the battery
positive (hot)
side.
Does the yellow
wire at starter
solenoid show
ground when
tested? Refer to
figure 13.
No
Do both wires
on RT steering
switch show
ground when
tested?
No
RT steering
switch is bad or
out of
adjustment.
Yes
Check starter
Problem could be
starter solenoid or
Yes
Do both wires
on LT steering
switch show
ground when
LT steering
switch is bad or
solenoid.
starter.
tested?
No
out of
adjustment.
Yes
Both wires show
Replace starter
VOLT METER
RED LEAD
STARTER SOLENOID
BLUE
BLACK LEAD
+
YELLOW
Figure 13
Does seat switch show ground on both yellow wires?
(Note: Wires must be installed on switch and seat switch
must be activated.)
Neither wire
shows ground.
Replace PTO
switch.
ground.
relay.
Only one wire
shows ground.
Replace seat
switch.
-
23
ENGINE WILL NOT CRANK
T
Test battery for
condition and
charge.
OK
Steering levers
out, PTO switch
'OFF', operator
on seat.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
terminal 'C' of
start fuse? Refer
to Figure 16.
No
Problem is the
key switch or
the power to the
key switch.
MODEL 718K and 720K.
(Kohler Command engines)
87
87a308586
Yes
Does voltage
appear from
terminal 'D' of
start fuse?
No
Replace start
fuse.
Yes
Does voltage
terminal 85 of
AB
30
REG.
C
7.5
START
7.5
E
PTO
G
7.5
LIGHT
Figure 16Figure 15
Yes
appear on
starter relay?
No
Check wires
from fuse to
starter relay.
NOTES:
1. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 42 on page 43.
D
F
H
Does voltage
appear on
terminal 87 of
starter relay?
No
Check in-line
fuse in wire
coming from the
starter.
Check starter
solenoid.
Problem could be
starter solenoid or
Yes
Does voltage
appear on
terminal 30 of
starter relay?
continues on
starter.
Yes
No
A
next page
KEY
SWITCH
IN START POSITION
BU
START FUSE
RD
+
-
S
L
M
G
B
STARTER
IN-LINE
FUSEH OLDER
BU
BU
STARTER
RELAY
YE
NC
Figure 14
24
SEAT
SWITCH
DRIVER
ON SEAT
SEAT
YE
BRAKE
NO
SWITCH
DIODE ALLOWS ENGINE
TO CRANK WITH
BRAKE SWITCH ON OR OFF
PTO
SWITCH
PTO OFF
YE
LEFT
STEER
STEERI NG LEVERS OU
LT
STR
YE
RIGHT
STEER
YE
RT
STR
GR
continued
A
Key switch is
now OFF.
You
are now testing
a ground circuit.
All tests will be
to the battery
positive (hot)
side.
Remove the
starter relay.
ENGINE WILL NOT CRANK
MODEL 718K and 720K.
(Kohler Command engines)
If all safety sw itches are correct, terminal 86
is grounded.
Terminal 87 is 12 volts.
Terminal 85 is + 12 volts when key switch is in
'START' position.
Terminal 30 is + 12 volts when relay is energized.
87
86
Blue Wire
Yellow Wire
Fuse h older
87a
Blue Wire
85
30
To pad T of circuit board
30
To battery
terminal of
starter
Fuse clip t o
regulator fuse
Does the yellow
wire
without
Yes
Replace starter
relay.
To input term inal of starter
the in-line fuse
show ground
when tested?
No
Do both wires
on RT steering
switch show
ground when
tested?
No
RT steering
switch is bad or
out of
adjustment.
Yes
Do both wires
on LT steering
switch show
ground when
tested?
No
LT steering
switch is bad or
out of
adjustment.
Yes
Does seat switch show ground on both yellow wires?
(Note: Wires must be installed on switch and seat switch
Only one wire
shows ground.
Replace seat
switch.
Note: Plug starter relay back in when finished testing.
To pad S of circuit board
Figure 17
must be activated.)
Neither wire
shows ground.
Replace PTO
switch.
25
ENGINE WILL NOT CRANK
Test battery for
condition and
charge.
OK
Steering levers
out, PTO switch
'OFF'. Voltage
tests are
performed with
a voltmeter or
test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
white wire of
starter solenoid
to ground?
No
MODEL 720
(Onan engine)
Check starter
Yes
solenoid.
Problem could
be starter
solenoid or
starter.
Does voltage
appear from
terminal 'J' of
start fuse to
ground?
No
Problem is the
key switch or
the power to the
key switch.
Yes
Does voltage
appear from
terminal 'I' of
start fuse to
ground?
No
Replace start
fuse.
Does yellow wire
Yes
in terminal 86 of
control relay B
show ground
when tested?
Do both wires
on LT steering
switch show
ground when
LT steering
switch is bad or
adjustment.
No
tested?
No
out of
Yes
Replace control
Yes
Do both wires
on RT steering
switch show
ground when
RT steering
switch is bad
adjustment.
relay B.
tested?
No
or out of
Yes
Replace PTO
switch.
26
ENGINE WILL NOT CRANK
MODEL 720
(Onan engine)
87
86 85
30
Figure 19
B
A
MAIN
PTO
E
IGN.
G
H
Figure 20
KEY
SWITCH
IN START POSITION PTO OFF STEERING LEVERS OUT
START FUSE
RD
+
B
-
R
S
A
I
BU
BU
BU
RELAY B
BU
STARTER
YE
PTO
SWITCH
RIGHT
STEER
RT
STR
YE
15
7.5
7.5
LEFT
STEER
GR
YE
30
REG.
START
30
LT
STR
C
D
F
J
I
Figure 18
27
ENGINE WILL NOT CRANK
Test battery for
condition and
charge.
OK
Steering levers
out and PTO
switch 'OFF'.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
terminal 'I' of
start fuse?
No
Problem is the
key switch or
the power to the
key switch.
MODEL 718D, 721, 721D, and
725
(All Kubota engines)
Does voltage
Yes
appear from
terminal 'J' of
start fuse?
No
Replace start
fuse.
Yes
Does voltage
appear on blue
wire at starter
solenoid.
continues on
next page
NOTES:
1. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 43 on page 43.
Yes
No
A
Check starter
solenoid.
Problem could
be starter
solenoid or
starter.
KEY
SWITCH
IN START POSITION PTO OFF STEERING LEVERS OUT
START FUSE
BU
+
-
RD
19
17
50
AC
30
BU
BU
RELAY B
BU
STARTER
YE
Figure 21
28
PTO
SWITCH
YE
RIGHT
STEER
RT
STR
LEFT
STEER
GR
LT
STR
YE
ENGINE WILL NOT CRANK
continued
A
Key switch is
now OFF.
You
are now testing
a ground circuit.
All tests will be
to the battery
positive (hot)
side.
Remove relay
'B'. (Note: Relay
'B' is the relay
with 3 blue wires
and 1 yellow wire
in plug.)
Does the yellow
wire on plug of
relay 'B' show
ground when
tested?
No
Do both yellow
wires on left
steering switch
test grounded?
No
Before replacing
steering switch,
check
adjustment. If it
does not click
when steering
levers are
moved in and
out adjust
switch.
MODEL 718D, 721, 721D, and
725
(All Kubota engines)
Yes
Yes
Replace
relay 'B'.
Do both yellow
wires on right
steering switch
test grounded?
No
Before replacing
steering switch,
check
adjustment. If it
does not click
when steering
levers are
moved in and
out adjust
switch.
Yes
Replace PTO
switch.
B
A
E
G
H
87
86 85
30
Figure 22
15
REG.
MAIN
PTO
7.5
START
IGN.
7.5
Figure 23
30
30
C
D
F
J
I
Replace left
steering switch.
Replace right
steering switch.
29
ENGINE WILL CRANK, BUT NOT START
If engine
cranks, but will
not run; the
safety switches
are functioning
properly.
Disconnect
yellow wire from
engine and test.
Does spark
occur at spark
plug?
No
This is an engine
related problem.
Consult engine
repair manual.
MODEL 612, 614, 616, 718, 718K, and 720K
(All engines)
Yes
Interlock module
or associated
wiring is
defective.
30
ENGINE WILL CRANK, BUT NOT START
PTO
7.5
7.5
REG.
30
15
MAIN
30
IGN.
START
A
D
E
G
F
J
B
C
I
H
Steering levers
out and PTO
switch 'OFF'.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
MODEL 720
(Onan engine)
NOTES:
1. All tests are made with wires in
place on their respective
switches.
2. Refer to fuse block diagram for
terminal locations.
3. Refer to 'Troubleshooting
Control Relays' for information
on the diode and control relays.
Key switch is in
'RUN' position for
each test.
4. If engine will crank, control relay
B cannot be the problem. This
means that the PTO switch,
right steering switch, and left
Yes
Yes
Yes
Yes
Replace ignition
coil.
Replace ignition
fuse.
Does voltage
appear from
terminal B of
main fuse to
ground?
No
Replace main
fuse.
Replace key
switch.
87
86 85
30
Yes
Does yellow wire
in terminal 85 of
control relay A
show ground?
Check yellow
wire to pad R or
diode from pad
No
A to pad R.
S
M
steering switch cannot be a
source of the problem.
Yes
Replace control
relay A.
M
P
L
GB
I
S
L
R
A
Y
G
T
Does voltage
appear from
white wire on
positive terminal
of ignition coil to
ground?
No
Does voltage
appear from
terminal 'G' of
ignition fuse to
ground?
No
Does voltage
appear from
terminal 'A' of
main fuse to
ground?
No
Does voltage
appear from
'B' (battery)
terminal of key
switch to ground?
No
Test battery.
Figure 27Figure 26Figure 25Figure 24
31
ENGINE WILL CRANK, BUT NOT START
Steering levers
out and PTO
switch 'OFF'.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch is in
'RUN' position for
each test.
Does voltage
appear from
black wire on
positive terminal
of ignition coil
to ground?
No
Does voltage
appear from
terminal 'G' of
ignition fuse
to ground?
No
Does voltage
appear from
terminal 'A' of
main fuse
to ground?
No
MODEL 721 and 725
(Kubota gasoline engines)
Yes
Yes
Yes
Problem is in
ignition coil or
distributor.
Consult Kubota
engine manual
for repair.
Replace ignition
fuse.
Does voltage
appear from
terminal B of
main fuse to
ground?
No
Replace main
fuse.
Yes
Replace control
relay A.
NOTES:
1. All tests are made with wires in
place on their respective
switches.
2. Refer to fuse block diagram for
terminal locations.
3. Refer to 'Troubleshooting
Control Relays' for information
on the diode and control relays.
4. If engine will crank, control relay
B cannot be the problem. This
means that the PTO switch,
right steering switch, and left
steering switch cannot be a
source of the problem.
30
REG.
30
C
D
F
J
B
15
A
MAIN
PTO
7.5
E
START
IGN.
7.5
G
Does voltage
appear from
Yes
Replace key
switch.
terminal 30
(battery) of key
switch to
ground?
No
Test battery.
H
I
Figure 28
MAIN
FUSE
KEY
SWITCH
IN RUN POSITION
RD
+
-
19
17
50
30
AC
RD
RD
BK
RELAY A
TO SAFETTY
YE
SWITCHES
RD
IGNITION
FUSE
IGNITION
COIL
COIL
BK
Figure 29
32
ENGINE WILL CRANK, BUT NOT START
Steering levers
out, PTO switch
'OFF'. Voltage
tests are
performed with
a voltmeter or
test light to
battery ground.
Key switch is
held in 'START'
position for each
test until
otherwise noted.
Does voltage
appear from
PULL
wire of
fuel solenoid to
ground?
No
Test in-line fuse
and fuse holder.
MODEL 718D and 721D
(Kubota diesel engines)
Yes
solenoid engage
while cranking?
Does
terminal of fuel
solenoid show
Repair ground
connection to
COMM
of fuel solenoid.
Does fuel
No
COMM
ground?
terminal
No
Yes
Yes
This is an engine
related problem.
Consult engine
repair manual for
further
information.
Does resistance
measure
approximately .2
to .5 ohms from
PULL
terminal to
COMM
terminal
of fuel solenoid.
No
Replace fuel
solenoid.
Yes
NOTES:
1. All tests are made with wires in
place on their respective
switches.
2. Refer to fuse block diagram for
terminal locations.
3. Refer to 'Troubleshooting
Control Relays' for information
on the diode and control relays.
4. If engine will crank, control relay
B cannot be the problem. This
means that the PTO switch,
right steering switch, and left
steering switch cannot be a
source of the problem.
Fuel solenoid
linkage is
binding or
sticking.
IN RUN POSITION
+
-
Battery Cable
KEY
SWITCH
50
19
AC
17
30
RD
RD
MAIN
FUSE
RD
BK
RELAY A
TO SAFETY
YE
SWITCHES
STARTER
Figure 30
33
BK
IGNITION
RD
FUSE
BK
BK
1
2
FUEL
SOLENOID
MODULE
GR
RD
FUSEHOLDER
WH
4
3
IN-LINE
HOLD
BK
FUEL
SOLENOID
COMM
PULL
ENGINE STARTS, BUT DIES
WHEN LEVERS ARE BROUGHT IN OR PTO SWITCH IS ENGAGED
Parking brake
'OFF'. Remove
plug from back
of brake switch.
With an ohm
meter test
through the
brake switch on
the posts that
were connected
to the yellow and
green wires
(figure 31).
Key switch is
'OFF' for each
test until
otherwise noted.
Does yellow wire
on brake switch
show ground
when tested?
No
Replace parking
brake switch.
MODELS 612, 614, 616 and 718 NOTES:
Yes
Replace interlock
module.
If the engine will crank and
start, both steering switches,
PTO switch and the seat switch
are functioning properly. The
problem must be the brake
switch or the interlock module.
Yellow
Green
NC NO
Brake switch
view.
Figure 31
34
ENGINE STARTS, BUT DIES
WHEN LEVERS ARE BROUGHT IN OR PTO SWITCH IS ENGAGED
Parking brake
'OFF'. Remove
plug from back of
brake switch.
With an ohm
meter test
through the
brake switch on
the posts that
were connected
to the two yellow
wires (figure 32).
Does brake
switch read
closed circuit
(0 ohms)?
No
Replace parking
brake switch.
MODELS 718K and 720K NOTES:
Yes
Replace interlock
module.
If the engine will crank and
start, both steering switches,
PTO switch and the seat switch
are functioning properly. The
problem must be the brake
switch or the interlock module.
Yellow
Yellow
NC NO
Brake switch
view.
Figure 32
35
ENGINE STARTS, BUT DIES
WHEN LEVERS ARE BROUGHT IN OR PTO SWITCH IS ENGAGED
Parking brake
'OFF', operator
'OFF' seat, all
wires are
connected to
switches. You
are testing a
ground circuit.
All tests will be
to the battery
positive (hot)
side.
Key switch is
'OFF' for each
test until
otherwise noted.
Do both yellow
and green wires
on brake switch
show ground
when tested
(figure 33)?
No
Replace parking
brake switch.
MODEL 720
(Onan engine)
Yes
Replace seat
NOTES:
If the engine will crank and
start, control relay A and control
relay B cannot be the problem.
The PTO switch, the left steering switch, and the right steering switch cannot be the problem. Therefore, the only
switches that can cause this
symptom are the seat switch
and the parking brake switch.
switch
Yellow
Green
NC NO
Brake switch
view.
Figure 33
36
ENGINE STARTS, BUT DIES
WHEN LEVERS ARE BROUGHT IN OR PTO SWITCH IS ENGAGED
Parking brake
'OFF', operator
'OFF' seat, all
wires are
connected to
switches. You
are testing a
ground circuit.
All tests will be
to the battery
positive (hot)
side.
Key switch is
'OFF' for each
test until
otherwise noted.
Do both yellow
and green wires
on brake switch
show ground
when tested
(figure 34)?
No
Replace parking
brake switch.
MODEL 718D, 721, 721D and 725
(All Kubota engines)
Yes
Replace seat
switch
NOTES:
If the engine will crank and
start, control relay A and control
relay B cannot be the problem.
The PTO switch, the left steering switch, and the right steering switch cannot be the problem. Therefore, the only
switches that can cause this
symptom are the seat switch
and the parking brake switch.
Yellow
Green
NC NO
Brake switch
view.
Figure 34
37
ENGINE STARTS, BUT DIES
WHEN KEY SWITCH IS RELEASED
Steering levers
out, PTO switch
'OFF' and
parking brake
'OFF'. Voltage
tests are
performed with a
voltmeter or test
light to battery
ground.
Key switch is in
'RUN' position for
each test.
Does voltage
appear from
terminal A of
main fuse to
ground?
No
Problem is the
key switch or
power to the key
switch.
MODEL 718D and 721D
(Kubota diesel engines)
Yes
Does voltage
appear from
terminal B of
main fuse to
ground?
No
Replace main
fuse.
Yes
Does voltage
appear from
terminal 1 of
fuel solenoid
module (figure
35) to ground?
No
Does voltage
appear from
terminal G of
ignition fuse to
ground?
No
Replace control
relay A. This is
the relay with 2
red, 1 yellow and
1 black wire.
Yes
terminal 2 of fuel
solenoid module
Yes
Does voltage
appear from
to battery
positive
?
No
Repair ground.
Replace ignition
fuse.
Yes
continues on next
1
Figure 35
A
page
4
23
38
B
A
E
G
H
15
MAIN
REG.
PTO
7.5
START
IGN.
7.5
Figure 36
30
30
C
D
F
J
I
ENGINE STARTS, BUT DIES
WHEN KEY SWITCH IS RELEASED
continued
A
Does voltage
appear from
terminal 4 of fuel
solenoid module
to ground?
No
Replace fuel
solenoid module.
MODEL 718D and 721D
(Kubota diesel engines)
Yes
Does voltage
appear from
'HOLD' wire of
fuel solenoid to
ground?
No
Check fuel
solenoid plug
connection
Yes
NOTES:
1. All tests are made with wires in
place on their respective
switches.
2. Problem is in the 'HOLD' circuit
of the fuel solenoid.
3. Relay 'A' is the relay with 1
yellow, 1 black, and 2 red
wires.
Problem is fuel
solenoid or
binding linkage.
Solenoid 'HOLD'
to 'COMM' wires
should test
approximately
14 to 16 ohms
resistance.
IN RUN POSITION
+
-
Battery Cable
KEY
SWITCH
50
19
AC
17
30
RD
RD
MAIN
FUSE
RD
BK
RELAY A
TO SAFETY
YE
SWITCHES
STARTER
Figure 37
39
BK
IGNITION
RD
FUSE
BK
BK
1
2
FUEL
SOLENOID
MODULE
GR
RD
FUSEHOLDER
WH
4
3
IN-LINE
HOLD
BK
FUEL
SOLENOID
COMM
PULL
Steering levers
out and PTO
switch 'ON'.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch in the
'RUN' position,
engine is
but
not running
.
TROUBLESHOOTING PTO CLUTCH
MODEL 612, 614, 616, 718,
718K and 720K
NOTES:
1. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 44 on page 44.
Does voltage
appear from
terminal 'E' of
PTO fuse to
ground (figure
39)?
No
Key switch or
wiring from key
switch to PTO
fuse is defective.
Yes
Does voltage
appear from
terminal 'F' of
PTO fuse to
ground?
No
Replace PTO
fuse.
Yes
Does voltage
brown wire at
PTO clutch plug
Replace PTO
appear from
to ground?
No
switch.
Yes
Does green wire
of PTO clutch
show ground?
Test ground
connections on
clutch.
No
Yes
Test PTO clutch
and terminals.
Verify air gap of
.012" on electric
clutch. (see
owner's manual.)
Test clutch by
reading ohm's
across clutch
disconnected).
Resistance
should measure
approximately
2.3 to 2.7 ohms.
plug (plug
KEY
SWITCH
IN RUN POSITION
RD
+
-
L
M
BSG
PTO
FUSE
BK
BR
PTO
SWITCH
PTO ON
BR
40
GR
CLUTCH
AB
30
REG.
C
7.5
7.5
7.5
D
F
H
START
E
PTO
G
LIGHT
Figure 39Figure 38
TROUBLESHOOTING PTO CLUTCH
Steering levers
out and PTO
switch 'ON'.
Voltage tests
are performed
with a voltmeter
or test light to
battery ground.
Key switch in the
'RUN' position,
but
engine is
not running.
Does voltage
appear from
terminal 'F' of
PTO fuse to
ground (figure
41)?
No
Replace PTO
fuse.
MODEL 718D, 720, 721, 721D,
and 725
Yes
Does voltage
appear from
brown wire at
PTO clutch plug
Replace PTO
to ground?
No
switch.
Yes
Does green wire
of PTO clutch
show ground?
Test ground
connections on
clutch.
NOTES:
1. If engine starts and runs, relay
'A' is working properly.
2. To see the wiring diagram for
models with serial numbers of
340725 and higher, refer to
figure 45 on page 44.
Yes
Test PTO clutch
and terminals.
No
Verify air gap of
.012" on electric
clutch. (see
owner's manual.)
Test clutch by
reading ohm's
across clutch
plug (plug
disconnected).
Resistance
should measure
approximately
2.3 to 2.7 ohms.
30
C
D
F
B
15
A
E
MAIN
PTO
7.5
REG.
START
IGN.
G
H
7.5
30
J
I
Figure 41
KEY
SWITCH
IN RUN POSITION
RD
+
-
19
17
50
AC
30
RD
MAIN
FUSE
RD
RELAY A
YE
BK
RD
TO SAFETY
SWITCHES
PTO
FUSE
BR
PTO
SWITCH
PTO ON
CLUTCH
BR
GR
Figure 40
41
1994 SUPPLEMENT
E
E
MODEL 612 and 616 - Starting Circuit.
(Briggs & Stratton engines)
Serial numbers of 340725 and higher,
refer to page 18 for troubleshooting.
KEY
SWITCH
IN START POSITION
BU
START FUSE
M
BSG
RD
+
-
L
BU
STARTER
SOLENOID
LEFT
STEER
STEERI NG LEVERS OUT
LT
STR
YE
Figure 40
YE
RIGHT
STEER
RT
STR
PTO
SWITCH
PTO OFF
YE
SEAT
SWITCH
DRIVER
ON SEAT
YE
SEAT
BRAKE
SWITCH
GR
NONC
YE
DIODE ALLOWS ENGINE
TO CRANK WITH BRAKE
SWITCH ON OR OFF
MODEL 718 - Starting Circuit.
(Briggs & Stratton Vanguard engines)
Serial numbers of 340725 and higher,
refer to page 20 for troubleshooting.
KEY
SWITCH
IN START POSITION
BU BU
START FUSE
M
BSG
RD
+
-
STARTER
SOLENOID
L
RIGHT
STEER
STEERI NG LEVERS OUT
YE
RT
STR
LEFT
STEER
YE
STR
Figure 41
LT
YE
PTO
SWITCH
PTO OFF
SEAT
SWITCH
DRIVER
ON SEAT
YE
SEAT
YE
DIODE ALLOWS ENGIN
TO CRANK WITH BRAK
SWITCH ON OR OFF
BRAKE
SWITCH
GR
NONC
42
1994 SUPPLEMENT
T
MODEL 718K and 720K - Starting Circuit.
(Kohler Command engines)
Serial numbers of 340725 and higher,
refer to page 24 for troubleshooting.
KEY
SWITCH
IN START POSITION
BU
BU
SEAT
SWITCH
DRIVER
ON SEAT
YE
PTO
SWITCH
PTO OFF
LEFT
STEER
STEERI NG LEVERS OU
RIGHT
STEER
YE
START FUSE
+
RD
-
S
L
M
G
B
STARTER
IN-LINE
FUSEH OLDER
BU
STARTER
RELAY
YE
SEAT
YE
NC
BRAKE
NO
SWITCH
DIODE ALLOWS ENGINE
TO CRANK WITH
BRAKE SWITCH ON OR OFF
YE
LT
STR
RT
STR
GR
Figure 42
MODEL 721, 721D and 725 - Starting Circuit.
(All Kubota engines)
Serial numbers of 340725 and higher,
refer to page 28 for troubleshooting.
KEY
SWITCH
IN START POSITION PTO OFF STEERING LEVERS OUT
START FUSE
BU
RD
+
-
19
17
50
AC
30
BU
BU
RELAY B
BU
Figure 43
STARTER
YE
PTO
SWITCH
YE
RIGHT
STEER
RT
STR
LEFT
STEER
GR
LT
STR
YE
43
1994 SUPPLEMENT
MODEL 612, 616, 718K and 720K - Clutch Circuit.
Serial numbers of 340725 and higher,
refer to page 40 for troubleshooting.
KEY
SWITCH
IN RUN POSITION
RD
+
-
L
M
BSG
BK
PTO
FUSE
BR
PTO
SWITCH
PTO ON
BR
CLUTCH
GR
Figure 44
MODEL 721, 721D and 725 - Clutch Circuit.
Serial numbers of 340725 and higher,
refer to page 41 for troubleshooting.
KEY
SWITCH
IN RUN POSITION
RD
+
-
19
17
50
AC
30
RD
MAIN
FUSE
RD
RELAY A
YE
BK
RD
TO SAFETY
SWITCHES
Figure 45
PTO
FUSE
PTO
SWITCH
PTO ON
CLUTCH
BR
BR
GR
44
45
46
47
48
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