Kohler 6600 Series User manual

132 690 03 Rev. I KohlerEngines.com
Service Manual
2 Safety
3 Maintenance
5 Specifications
21 Tools and Aids
24 Troubleshooting
28 Air Cleaner/Intake
30 Fuel System
49 Governor System
50 Lubrication System
52 Electrical System
59 Starter System
63 Emission Compliant Systems
66 Disassembly/Inspection and Service
79 Reassembly
IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating
instruction of equipment that this engine powers.
Ensure engine is stopped and level before performing any maintenance or service.
KT610-KT620, KT715-KT745

2
Safety
SAFETY PRECAUTIONS
WARNING: A hazard that could result in death, serious injury, or substantial property damage.
CAUTION: A hazard that could result in minor personal injury or property damage.
NOTE: is used to notify people of important installation, operation, or maintenance information.
WARNING
Explosive Fuel can cause
fires and severe burns.
Do not fill fuel tank while
engine is hot or running.
Gasoline is extremely flammable
and its vapors can explode if
ignited. Store gasoline only in
approved containers, in well
ventilated, unoccupied buildings,
away from sparks or flames.
Spilled fuel could ignite if it comes
in contact with hot parts or sparks
from ignition. Never use gasoline
as a cleaning agent.
WARNING
Rotating Parts can cause
severe injury.
Stay away while engine
is in operation.
Keep hands, feet, hair, and
clothing away from all moving
parts to prevent injury. Never
operate engine with covers,
shrouds, or guards removed.
WARNING
Carbon Monoxide can
cause severe nausea,
fainting or death.
Avoid inhaling exhaust
fumes.
Engine exhaust gases contain
poisonous carbon monoxide.
Carbon monoxide is odorless,
colorless, and can cause death if
inhaled.
WARNING
Accidental Starts can
cause severe injury or
death.
Disconnect and ground
spark plug lead(s) before
servicing.
Before working on engine or
equipment, disable engine as
follows: 1) Disconnect spark plug
lead(s). 2) Disconnect negative (–)
battery cable from battery.
WARNING
Hot Parts can cause
severe burns.
Do not touch engine
while operating or just
after stopping.
Never operate engine with heat
shields or guards removed.
WARNING
Cleaning Solvents can
cause severe injury or
death.
Use only in well
ventilated areas away
from ignition sources.
Carburetor cleaners and solvents
are extremely flammable. Follow
cleaner manufacturer’s warnings
and instructions on its proper and
safe use. Never use gasoline as a
cleaning agent.
CAUTION
Electrical Shock can
cause injury.
Do not touch wires while
engine is running.
CAUTION
Damaging Crankshaft
and Flywheel can cause
personal injury.
Using improper procedures can
lead to broken fragments. Broken
fragments could be thrown from
engine. Always observe and use
precautions and procedures when
installing flywheel.
KohlerEngines.com 32 690 03 Rev. I

3
Maintenance
32 690 03 Rev. I KohlerEngines.com
MAINTENANCE INSTRUCTIONS
WARNING
Before working on engine or equipment, disable engine as
follows: 1) Disconnect spark plug lead(s). 2) Disconnect
negative (–) battery cable from battery.
Accidental Starts can cause severe injury or
death.
Disconnect and ground spark plug lead(s)
before servicing.
Normal maintenance, replacement or repair of emission control devices and systems may be performed by any repair
establishment or individual; however, warranty repairs must be performed by a Kohler authorized dealer.
MAINTENANCE SCHEDULE
Every 25 Hours¹
●Service/replace precleaner. Air Cleaner/Intake
●Replace LPAC element (if not equipped with precleaner). Air Cleaner/Intake
Every 50 Hours¹
●Replace LPAC element (if equipped with precleaner). Air Cleaner/Intake
●Replace high performance air cleaner element (if not equipped with precleaner). Air Cleaner/Intake
Every 75 Hours¹
●Replace high performance air cleaner element (if equipped with precleaner). Air Cleaner/Intake
●Replace PRO performance air cleaner element (if not equipped with precleaner). Air Cleaner/Intake
Every 100 Hours¹
●Replace PRO performance air cleaner element (if equipped with precleaner). Air Cleaner/Intake
●Change oil and filter. Lubrication System
●Remove cooling shrouds and clean cooling areas. Air Cleaner/Intake
Every 100 Hours
●Check that all fasteners are in place and components are properly secured. Reassembly
●Replace fuel filter.
Every 500 Hours²
●Have valve lash checked/adjusted. Reassembly
Every 500 Hours
●Replace spark plugs and set gap. Electrical System
¹ Perform these procedures more frequently under severe, dusty, dirty conditions.
² Have a Kohler authorized dealer perform this service.
REPAIRS/SERVICE PARTS
Kohler genuine service parts can be purchased from Kohler authorized dealers. To find a local Kohler authorized
dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada).

4
Maintenance
KohlerEngines.com 32 690 03 Rev. I
OIL RECOMMENDATIONS
We recommend use of Kohler oils for best performance.
Other high-quality detergent oils (including synthetic)
of API (American Petroleum Institute) service class SJ
or higher are acceptable. Select viscosity based on
air temperature at time of operation as shown in table
below.
°F -20 020324060
50 80 100
°C -30 -20 -10 0 10 20 30 40
5W-30
10W-30
SAE 30
FUEL RECOMMENDATIONS
WARNING
Explosive Fuel can cause fires and severe
burns.
Do not fill fuel tank while engine is hot or
running.
Gasoline is extremely flammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well ventilated, unoccupied buildings,
away from sparks or flames. Spilled fuel could ignite
if it comes in contact with hot parts or sparks from
ignition. Never use gasoline as a cleaning agent.
NOTE: E15, E20 and E85 are NOT approved and
should NOT be used; effects of old, stale or
contaminated fuel are not warrantable.
Fuel must meet these requirements:
●Clean, fresh, unleaded gasoline.
●Octane rating of 87 (R+M)/2 or higher.
●Research Octane Number (RON) 90 octane minimum.
●Gasoline up to 10% ethyl alcohol, 90% unleaded is
acceptable.
●Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blend (max 15% MTBE by volume) are
approved.
●Do not add oil to gasoline.
●Do not overfill fuel tank.
●Do not use gasoline older than 30 days.
STORAGE
If engine will be out of service for 2 months or more
follow procedure below.
1. Add Kohler PRO Series fuel treatment or equivalent
to fuel tank. Run engine 2-3 minutes to get stabilized
fuel into fuel system (failures due to untreated fuel
are not warrantable).
2. Change oil while engine is still warm from operation.
Remove spark plug(s) and pour about 1 oz. of
engine oil into cylinder(s). Replace spark plug(s) and
crank engine slowly to distribute oil.
3. Disconnect negative (–) battery cable.
4. Store engine in a clean, dry place.

5
Specifications
32 690 03 Rev. I KohlerEngines.com
Engine Dimensions with Low Profile or High Performance Air Cleaner-Flywheel Side
F
E
G
H
I
M
A
B
D
C
J
K
L
A423.0 mm (16.65 in.) B136.7 mm (5.38 in.) C89.6 mm (3.53 in.) D50.1 mm (1.97 in.)
EOil Fill and Dipstick
(Yellow) FFuel Line Connection Point GMounting Hole "A" H136.9 mm (5.39 in.)
I141.5 mm (5.57 in.) J89.7 mm (3.53 in.) K307.9 mm (12.12 in.) L7.2 mm (0.28) Center
of Gravity
M45.5 mm (1.79 in.)
Center of Gravity

6
Specifications
KohlerEngines.com 32 690 03 Rev. I
Engine Dimensions with Low Profile or High Performance Air Cleaner-Oil Filter Side
AB
C
DEF
G
H
IJ
K
L
M
A355.1 mm (13.98 in.) Low Profile Air
Cleaner Removal B329.1 mm (12.96 in.)
Top of Low Profile
Air Cleaner C159.4 mm (6.28 in.)
Center of Gravity DEngine Mounting Surface
E80.3 mm (3.16 in.)
Oil Filter FMounting Hole "A" G51.2 mm (2.02 in.) Oil Filter H134.0 mm (5.28 in.)
Spark Plug Center
Line
I340.9 mm (13.42 in.) J380.7 mm (14.99 in.) KOptional Fixed Guard L
392.1 mm (15.44 in.)
High Performance
Air Cleaner
Removal
M
354.2 mm (13.94 in.)
Top of High
Performance Air
Cleaner

7
Specifications
32 690 03 Rev. I KohlerEngines.com
Engine Dimensions with Low Profile or High Performance Air Cleaner-Engine Mounting Surface (PTO End)
A
BB C
E
F
G
HI
J
L
PN
M
O
D
T
S
R
K
G
LL
Q
U
A334.3 mm (13.16 in.) B72.8 mm (2.87 in.) C94.3 mm (3.71 in.) D48.1 mm (1.89 in.)
EEvap Connection
Point F
4 X 5/16-18
UNC-2B in.
16.5 mm (0.649 in.)
Deep No Studs
G30° H50.0 mm (1.97 in.)
Exhaust Port #2
I268.3 mm (10.56 in.) J104.0 mm (4.10 in.) K242.1 mm (9.53 in.) L89.8 mm (3.54 in.)
M18.0 mm (0.71 in.)
Oil Filter Removal N116.8 mm (4.60 in.) OMounting Hole "A" PRotation Direction
Q248.1 mm (9.77 in.)
Starter Stud R
4 X 9.005 mm (0.355
in.) 37.0 mm (1.46
in.) Deep on a Ø
254.0 mm (10.0 in.)
B.C.
S93.1 mm (3.66 in.)
Starter Stud T
312.0 mm (12.28 in.)
Throttle and Choke
Cable Mounting
Surface
U50.0 mm (1.97 in.)
Exhaust Port #1

8
Specifications
KohlerEngines.com 32 690 03 Rev. I
Engine Dimensions with Low Profile or High Performance Air Cleaner-Starter Side
A
B
C
D
E
FG
H
A55.8 mm (2.20 in.)
Starter Stud B13.0 mm (0.51 in.) CMounting Hole "A" D40.8 mm (1.61 in.)
EEngine Mounting
Surface F72.0 mm (2.83 in.) Exhaust Port #2 G92.0 mm (3.62 in.) Exhaust Port #1 H154.0 mm (6.06 in.)
Spark Plug Center
Line

9
Specifications
32 690 03 Rev. I KohlerEngines.com
Engine Dimensions with Low Profile or High Performance Air Cleaner-Valve Cover Side
A
B
C
D
E
F
A87.6 mm (3.45 in.) BEngine Mounting
Surface C152.9 mm (6.02 in.) D4.4 mm (0.17 in.)
EMounting Hole "A" F39.8 mm (1.57 in.)

10
Specifications
KohlerEngines.com 32 690 03 Rev. I
Engine Dimensions with PRO Performance Air Cleaner-Flywheel Side
F
EG
H
I
K
A
B
D
C
J
L
M
A424.7 mm (16.72 in.) B136.7 mm (5.38 in.) C89.6 mm (3.53 in.) D50.1 mm (1.97 in.)
EOil Fill and Dipstick
(Yellow) FFuel Line Connection Point G136.9 mm (5.39 in.) HMounting Hole "A"
I141.5 mm (5.57 in.) J89.7 mm (3.53 in.) K9.7 mm (0.38 in.)
Center of Gravity L307.9 mm (12.12 in.)
M47.0 mm (1.85 in.)
Center of Gravity

11
Specifications
32 690 03 Rev. I KohlerEngines.com
Engine Dimensions with PRO Performance Air Cleaner-Oil Filter Side
A
B
C
D
EFG
H
I
L
M
K
J
A458.7 mm (18.06 in.) Air Cleaner
Removal B398.7 mm (15.70 in.)
Top of Air Cleaner C265.2 mm (10.44 in.)
Evap Connection
Point D166.5 mm (6.56 in.)
Center of Gravity
EEngine Mounting
Surface F80.3 mm (3.16 in.) Oil Filter GMounting Hole "A" H51.2 mm (2.02 in.) Oil Filter
I134.0 mm (5.28 in.) Spark Plug Center
Line J340.9 mm (13.42 in.) K380.7 mm (14.99 in.) LOptional Fixed Guard
M272.0 mm (10.71 in.) Evap Connection
Point

12
Specifications
KohlerEngines.com 32 690 03 Rev. I
Engine Dimensions with PRO Performance Air Cleaner-Engine Mounting Surface (PTO End)
A
B B C
E
F
G
H
I
J
L
P
N
M
O
D
S
R
K
Q
E
N
A334.3 mm (13.16 in.) B72.8 mm (2.87 in.) C94.3 mm (3.71 in.) D4 X 5/16-18 UNC-2B in. 16.5 mm (0.649
in.) Deep No Studs
E30° F50.0 mm (1.97 in.)
Exhaust Port #2 G242.1 mm (9.53 in.) H104.0 mm (4.10 in.)
I89.8 mm (3.54 in.) J18.0 mm (0.71 in.)
Oil Filter Removal K116.8 mm (4.60 in.) LMounting Hole "A"
M248.1 mm (9.77 in.)
Starter Stud N89.8 mm (3.54 in.) ORotation Direction P
4 X 9.005 mm
(0.355 in.) 37 mm
(1.46 in.) Deep on
a Ø
254 mm (10.0 in.)
B.C.
Q93.1 mm (3.66 in.)
Starter Stud R
312.0 mm (12.28 in.)
Throttle and
Choke Cable
Mounting Surface
S50.0 mm (1.97 in.)
Exhaust Port #1

13
Specifications
32 690 03 Rev. I KohlerEngines.com
Engine Dimensions with PRO Performance Air Cleaner-Starter Side
A
B
C
D
E
FG
H
A55.8 mm (2.20 in.)
Starter Stud B13.0 mm (0.51 in.) CMounting Hole "A" D40.8 mm (1.61 in.)
EEngine Mounting
Surface F72.0 mm (2.83 in.) Exhaust Port #2 G92.0 mm (3.62 in.) Exhaust Port #1 H154.0 mm (6.06 in.)
Spark Plug Center
Line

14
Specifications
KohlerEngines.com 32 690 03 Rev. I
Engine Dimensions with PRO Performance Air Cleaner-Valve Cover Side
A
B
C
D
E
F
A87.6 mm (3.45 in.) BEngine Mounting
Surface C152.9 mm (6.02 in.) D4.4 mm (0.17 in.)
EMounting Hole "A" F39.8 mm (1.57 in.)

15
Specifications
32 690 03 Rev. I KohlerEngines.com
GENERAL SPECIFICATIONS3,6 KT610 KT620 KT715 KT725 KT730 KT735 KT740* KT745
Bore 83 mm (3.27 in.)
Stroke 61 mm
(2.4 in.) 67 mm (2.64 in.) 69 mm (2.72 in.)
Displacement 660 cc
(40.3 cu. in.) 725 cc (44 cu. in.) 747 cc (46 cu. in.)
Oil Capacity (refill) 1.9 l (2.0 qt.)
Maximum Angle of Operation (@ full oil level)425°
*KT740 engines with PRO Performance Air Cleaner have 747 cc (46 cu. in.) Displacement.
TORQUE SPECIFICATIONS3,5 KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Auto Choke
eChoke™
Stepper Motor to Bracket Fastener
Air Cleaner Base to Mounting Studs
3.1 N·m (27.4 in. lb.)
6.2-7.3 N·m (55-65 in. lb.)
Smart-Choke™
Air Vane Deflector to Intake Manifold
Air Cleaner Base to Mounting Studs
Bracket Assembly Screw
1 N·m (9 in. lb.)
6.2-7.3 N·m (55-65 in. lb.)
5 N·m (45 in. lb.)
Baffle and Sheet Metal into Aluminum
M5 Thread Forming Fasteners 8.5 N·m (75 in. lb.) into new hole
4.0 N·m (35 in. lb.) into used hole
M6 Thread Forming Fasteners 10.7 N·m (95 in. lb.) into new hole
7.3 N·m (65 in. lb.) into used hole
Blower Housing and Sheet Metal
M3 HI-LO Screw 2.3 N·m (20 in. lb.)
M4 HI-LO Screw 2.8 N·m (25 in. lb.)
M5 Fasteners 6.2 N·m (55 in. lb.) into new hole
4.0 N·m (35 in. lb.) into used hole
M6 Fasteners 10.7 N·m (95 in. lb.) into new hole
7.3 N·m (65 in. lb.) into used hole
ENGINE IDENTIFICATION NUMBERS
Kohler engine identification numbers (model, specification and serial) should be referenced for efficient repair,
ordering correct parts, and engine replacement.
Model. . . . . . . . . . . . . . . . . . . . . KT715
7000 Series Engine
Numerical Designation
Specification . . . . . . . . . . . . . . . KT715-0001
Serial . . . . . . . . . . . . . . . . . . . . . 4423500328
Year Manufactured Code Factory Code
Code Year
44 2014
45 2015
46 2016
3 Values are in Metric units. Values in parentheses are English equivalents.
4Exceeding maximum angle of operation may cause engine damage from insufficient lubrication.
5Lubricate threads with engine oil prior to assembly.
6Any and all horsepower (hp) references by Kohler are Certified Power Ratings and per SAE J1940 & J1995 hp
standards. Details on Certified Power Ratings can be found at KohlerEngines.com.

16
Specifications
KohlerEngines.com 32 690 03 Rev. I
TORQUE SPECIFICATIONS3,5 KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Carburetor
Mounting Nut 6.2-7.3 N·m (55-65 in. lb.)
Connecting Rod
Cap Fastener (torque in increments)
Black Coating
Gray Metallic Coating
11.3 N·m (100 in. lb.)
13.6 N·m (120 in. lb.)
Crankcase
Breather Assembly
Outer Cover Stud
Outer Cover Hex Nut
6.2 N·m (55 in. lb.) into new hole
4.0 N·m (35 in. lb.) into used hole
1.3 N·m (11.5 in. lb.)
Oil Drain Plug 13.6 N·m (10 ft. lb.)
Cylinder Head
Head Bolt Fastener (torque in 2 increments) first to 22.6 N·m (200 in. lb.)
finally to 41.8 N·m (370 in. lb.)
Rocker Arm Stud 11.3 N·m (100 in. lb.)
Flywheel
Retaining Screw 74.5 N·m (55 ft. lb.)
Fuel Pump
Screw 2.8 N·m (25 in. lb.)
Governor
Lever Nut 6.8 N·m (60 in. lb.)
Ignition
Spark Plug 27 N·m (20 ft. lb.)
Module Fastener 4.0-6.2 N·m (35-55 in. lb.)
Rectifier-Regulator Fastener 4.0 N·m (35 in. lb.)
Intake Manifold
Mounting Fastener (torque in 2 increments) first to 7.4 N·m (66 in. lb.)
finally to 9.9 N·m (88 in. lb.)
Muffler
M8 Hex Nuts 24.4 N·m (216 in. lb.)
5/16-18 Capscrew 16.9 N·m (150 in. lb.)
Bracket Screw 9.9 N·m (88 in. lb.)
Oil Pan
Fastener 24.4 N·m (216 in. lb.)
Oil Pump
Screw (no torque sequence) 9.9 N·m (88 in. lb.)
Oil Sentry™
Pressure Switch 4.5 N·m (40 in. lb.)
3 Values are in Metric units. Values in parentheses are English equivalents.
5Lubricate threads with engine oil prior to assembly.

17
Specifications
32 690 03 Rev. I KohlerEngines.com
TORQUE SPECIFICATIONS3,5 KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Solenoid (Starter)
Mounting Hardware 4.0-6.0 N·m (35-53 in. lb.)
Nut, Positive (+) Brush Lead 8.0-11.0 N·m (71-97 in. lb.)
Speed Control Bracket
Fastener 10.7 N·m (95 in. lb.) into new holes
7.3 N·m (65 in. lb.) into used holes
Starter Assembly
Thru Bolt
Inertia Drive
Solenoid Shift
4.5-5.7 N·m (40-50 in. lb.)
5.6-9.0 N·m (49-79 in. lb.)
Mounting Screw 23.8 N·m (211 in. lb.)
Brush Holder Mounting Screw 2.5-3.3 N·m (22-29 in. lb.)
Stator
Mounting Screw 8.8 N·m (78 in. lb.)
Valve Cover
Fastener 9.6 N·m (85 in. lb.)
CLEARANCE SPECIFICATIONS3KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Camshaft
End Play 0.06/0.40 mm (0.0024/0.0157 in.)
Running Clearance 0.040/0.077 mm (0.0016/0.0030 in.)
Bore I.D.
New
Max. Wear Limit
20.000/20.025 mm (0.7874/0.7884 in.)
20.038 mm (0.7889 in.)
Bearing Surface O.D.
New
Max. Wear Limit
19.948/19.960 mm (0.7854/0.7858 in.)
19.945 mm (0.7852 in.)
Connecting Rod
Connecting Rod-to-Crankpin Running Clearance
New
Max. Wear Limit
0.037/0.083 mm (0.0015/0.0033 in.)
0.098 mm (0.0039 in.)
Connecting Rod-to-Crankpin Side Clearance 0.261/0.67 mm (0.0102/0.0264 in.)
Connecting Rod-to-Piston Pin Running Clearance 0.013/0.032 mm (0.0005/0.0013 in.)
Piston Pin End I.D.
New
Max. Wear Limit
17.013/17.027 mm (0.6698/0.6704 in.)
17.040 mm (0.6709 in.)
Crankcase
Governor Cross Shaft Bore I.D.
New
Max. Wear Limit
8.025/8.075 mm (0.3159/0.3179 in.)
8.088 mm (0.3184 in.)
3 Values are in Metric units. Values in parentheses are English equivalents.
5Lubricate threads with engine oil prior to assembly.

18
Specifications
KohlerEngines.com 32 690 03 Rev. I
CLEARANCE SPECIFICATIONS3KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Crankshaft
End Play (free) 0.075/0.595 mm (0.0030/0.023 in.)
Bore (in crankcase)
New
Max. Wear Limit
40.974/40.987 mm (1.6131/1.6137 in.)
41.000 mm (1.6142 in.)
Bore (in oil pan)
New 40.974/41.000 mm (1.6457/1.6142 in.)
Crankshaft Bore (in oil pan)-to-Crankshaft
Running Clearance
New 0.039/0.087 mm (0.0015/0.0034 in.)
Flywheel End Main Bearing Journal
O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round
40.913/40.935 mm (1.6107/1.6116 in.)
40.840 mm (1.608 in.)
0.022 mm (0.0009 in.)
0.025 mm (0.0010 in.)
Oil Pan End Main Bearing Journal
O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round
40.913/40.935 mm (1.6107/1.6116 in.)
40.840 mm (1.608 in.)
0.022 mm (0.0009 in.)
0.025 mm (0.0010 in.)
Connecting Rod Journal
O.D. - New
O.D. - Max. Wear Limit
Max. Taper
Max. Out-of-Round
35.950/35.974 mm (1.4154/1.4163 in.)
35.950 mm (1.4154 in.)
0.018 mm (0.0007 in.)
0.025 mm (0.0010 in.)
T.I.R.
PTO End, Crank in Engine
Entire Crank, in V-Blocks
0.279 mm (0.0110 in.)
0.200 mm (0.0079 in.)
Cylinder Bore
Bore I.D.
New
Max. Wear Limit
Max. Out-of-Round
Max. Taper
83.006/83.031 mm (3.2679/3.2689 in.)
83.069 mm (3.2704 in.)
0.120 mm (0.0047 in.)
0.050 mm (0.0020 in.)
Cylinder Head
Max. Out-of-Flatness 0.076 mm (0.003 in.)
Governor
7 mm Hex End Cross Shaft End Play 0.25/3.15 mm (0.010/0.124 in.)
Governor Cross Shaft-to-Crankcase Running
Clearance 0.025/0.126 mm (0.0009/0.0049 in.)
Cross Shaft O.D.
New
Max. Wear Limit
7.949/8.000 mm (0.3129/0.3149 in.)
7.936 mm (0.3124 in.)
Governor Gear Shaft-to-Governor Running
Clearance
0.050/0.210 mm (0.0020/0.0083 in.)
Gear Shaft O.D.
New
Max. Wear Limit
5.990/6.000 mm (0.2358/0.2362 in.)
5.977 mm (0.2353 in.)
3 Values are in Metric units. Values in parentheses are English equivalents.

19
Specifications
32 690 03 Rev. I KohlerEngines.com
3 Values are in Metric units. Values in parentheses are English equivalents.
7 Measure 6 mm (0.2362 in.) above bottom of piston skirt at right angles to piston pin.
CLEARANCE SPECIFICATIONS3KT610 KT620 KT715 KT725 KT730 KT735 KT740 KT745
Ignition
Spark Plug Gap 0.76 mm (0.030 in.)
Module Air Gap 0.203/0.305 mm (0.008/0.012 in.)
Piston, Piston Rings, and Piston Pin
Piston-to-Piston Pin Running Clearance 0.006/0.017 mm (0.0002/0.0007 in.)
Pin Bore I.D.
New
Max. Wear Limit
17.006/17.012 mm (0.6695/0.6698 in.)
17.025 mm (0.6703 in.)
Pin O.D.
New
Max. Wear Limit
16.995/17.000 mm (0.6691/0.6693 in.)
16.994 mm (0.6691 in.)
Top Compression Ring-to-Groove Side Clearance 0.030/0.070 mm (0.001/0.0026 in.)
Middle Compression Ring-to-Groove Side
Clearance
0.030/0.070 mm (0.001/0.0026 in.)
Oil Control Ring-to-Groove Side Clearance 0.060/0.190 mm (0.0022/0.0073 in.)
Top Compression Ring End Gap
New Bore
Used Bore (Max.)
Middle Compression Ring End Gap
New Bore
Used Bore (Max.)
0.189/0.277 mm (0.0074/0.0109 in.)
0.531 mm (0.0209 in.)
1.519/1.797 mm (0.0598/0.0708 in.)
2.051 mm (0.0808 in.)
Thrust Face O.D.7
New
Max. Wear Limit
82.978 mm (3.2668 in.)
82.833 mm (3.2611 in.)
Piston Thrust Face-to-Cylinder Bore7Running
Clearance
New
0.019/0.062 mm (0.0007/0.0024 in.)
Valves and Valve Tappets
Clearance 0.101/0.152 mm (0.0040/0.0060 in.)
Valve Tappet to Crankcase Running Clearance 0.013/0.073 mm (0.0005/0.0029 in.)
Intake Valve Stem-to-Valve Guide Running
Clearance
0.040/0.0780 mm (0.0016/0.0031 in.)
Exhaust Valve Stem-to-Valve Guide Running
Clearance
0.052/0.090 mm (0.0020/0.0035 in.)
Intake Valve Guide I.D.
New
Max. Wear Limit
7.040/7.060 mm (0.2772/0.2780 in.)
7.140 mm (0.2811 in.)
Exhaust Valve Guide I.D.
New
Max. Wear Limit
7.040/7.060 mm (0.2772/0.2780 in.)
7.160 mm (0.2819 in.)
Valve Guide Reamer Size
Standard
0.25 mm O.S.
7.050 mm (0.2776 in.)
7.300 mm (0.2874 in.)
Intake Valve Minimum Lift 8.500 mm (0.3346 in.)
Exhaust Valve Minimum Lift 8.500 mm (0.3346 in.)
Nominal Valve Face Angle 45°

20
Specifications
KohlerEngines.com 32 690 03 Rev. I
GENERAL TORQUE VALUES
Metric Fastener Torque Recommendations for Standard Applications
Property Class Noncritical
Fasteners
Into Aluminum
Size 4.8 5.8 8.8 10.9 12.9
Tightening Torque: N·m (in. lb.) ± 10%
M4 1.2 (11) 1.7 (15) 2.9 (26) 4.1 (36) 5.0 (44) 2.0 (18)
M5 2.5 (22) 3.2 (28) 5.8 (51) 8.1 (72) 9.7 (86) 4.0 (35)
M6 4.3 (38) 5.7 (50) 9.9 (88) 14.0 (124) 16.5 (146) 6.8 (60)
M8 10.5 (93) 13.6 (120) 24.4 (216) 33.9 (300) 40.7 (360) 17.0 (150)
Tightening Torque: N·m (ft. lb.) ± 10%
M10 21.7 (16) 27.1 (20) 47.5 (35) 66.4 (49) 81.4 (60) 33.9 (25)
M12 36.6 (27) 47.5 (35) 82.7 (61) 116.6 (86) 139.7 (103) 61.0 (45)
M14 58.3 (43) 76.4 (56) 131.5 (97) 184.4 (136) 219.7 (162) 94.9 (70)
Torque Conversions
N·m = in. lb. x 0.113 in. lb. = N·m x 8.85
N·m = ft. lb. x 1.356 ft. lb. = N·m x 0.737
English Fastener Torque Recommendations for Standard Applications
Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 or 5 Fasteners
Into Aluminum
Size Grade 2 Grade 5 Grade 8
Tightening Torque: N·m (in. lb.) ± 20%
8-32 2.3 (20) 2.8 (25) — 2.3 (20)
10-24 3.6 (32) 4.5 (40) — 3.6 (32)
10-32 3.6 (32) 4.5 (40) — —
1/4-20 7.9 (70) 13.0 (115) 18.7 (165) 7.9 (70)
1/4-28 9.6 (85) 15.8 (140) 22.6 (200) —
5/16-18 17.0 (150) 28.3 (250) 39.6 (350) 17.0 (150)
5/16-24 18.7 (165) 30.5 (270) — —
3/8-16 29.4 (260) — — —
3/8-24 33.9 (300) — — —
Tightening Torque: N·m (ft. lb.) ± 20%
5/16-24 — — 40.7 (30) —
3/8-16 — 47.5 (35) 67.8 (50) —
3/8-24 — 54.2 (40) 81.4 (60) —
7/16-14 47.5 (35) 74.6 (55) 108.5 (80) —
7/16-20 61.0 (45) 101.7 (75) 142.5 (105) —
1/2-13 67.8 (50) 108.5 (80) 155.9 (115) —
1/2-20 94.9 (70) 142.4 (105) 223.7 (165) —
9/16-12 101.7 (75) 169.5 (125) 237.3 (175) —
9/16-18 135.6 (100) 223.7 (165) 311.9 (230) —
5/8-11 149.5 (110) 244.1 (180) 352.6 (260) —
5/8-18 189.8 (140) 311.9 (230) 447.5 (330) —
3/4-10 199.3 (147) 332.2 (245) 474.6 (350) —
3/4-16 271.2 (200) 440.7 (325) 637.3 (470) —