Kohler ZT740

Kohler ZT740The Kohler ZT740 is a 747 cc (45.6 cu·in) natural aspirated V-twin four-stroke air-cooled internal combustion small gasoline engine from the Confidant series with a vertical shaft, manufactured by Kohler Co for general-purpose applications.

A 83.0 mm (3.27 in) cylinder bore and 69.0 mm (2.70 in) piston stroke give the ZT740 engine a total of 747 cc of displacement. The compression ratio rating is 9.1:1.

The ZT740 engine produced 25.3 PS (18.6 KW; 25.0 HP) at 3,600 rpm of maximum horsepower and 57.5 Nm (5.9 kg·m; 42.4 ft·lb) at 2,400 rpm of maximum torque.

The Kohler ZT740 features:

  • High-impact nylon shroud and valve cover
  • OHV design
  • Aluminum cylinder block
  • Cast iron cylinder liners
  • Electronic ignition system
  • Carburetor with fixed main jet (Walbro or Keihin)
  • Mechanical centrifugal governor
  • Full pressure lubrication system
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine modelConfidant ZT740
Engine type4-stroke, OHV, V-twin
Displacement747 cm3, (45.6 cu·in)
Max. horsepower25.3 PS (18.6 KW; 25.0 HP) at 3,600 rpm
Max. torque57.5 Nm (5.9 kg·m; 42.4 ft·lb) at 2,400 rpm
Cooling systemForced air
Air cleanerHeavy-duty air cleaner
Lubricating systemFull pressure
Ignition systemElectronic ignition system
Fuel systemCarburetor with fixed main jet (Walbro or Keihin)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemElectric starter
GovernorMechanical centrifugal governor
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)478 x 443 x 431 mm (18.8 × 17.5 × 17.0 in)
Dry weight41.3 kg (91.0 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:9.1:1
Cylinder bore:83.0 mm (3.27 in)
Piston stroke:69.0 mm (2.70 in)
Cylinder internal diameter (standard):82.988-83.013 mm (3.2672-3.2682 in)
Thrust face outer diameter (standard):82.978 mm (3.2668 in)
Piston pin diameter:16.995-17.000 mm (0.6691-0.6693 in)
Number of piston rings (compression / oil):2/1
Side clearance (Top):0.030-0.070 mm (0.0010-0.0026 in)
Side clearance (Second):0.030-0.070 mm (0.0010-0.0026 in)
Side clearance (Oil):0.060-0.190 mm (0.0022-0.0073 in)
Ring end gap (Top):0.189-0.277 mm (0.0074-0.0109 in)
Ring end gap (Second):1.519-1.797 mm (0.0598-0.0708 in)
Number of main bearings:2
Crankshaft main journal diameter:40.913-40.935 mm (1.6107-1.6116 in)
Crankpin journal diameter:35.950-35.974 mm (1.4154-1.4163 in)
Cylinder head
Valve arrangement:OHV, gear driven
Valves:2 (4 valves in total)
Valve head diameter (INTAKE):33.370-33.630 mm (1.3138-1.324 in)
Valve head diameter (EXHAUST):29.370-29.630 mm (1.1563-1.1665 in)
Valve seat angle (INTAKE):89°
Valve seat angle (EXHAUST):89°
Valve seat angle (INTAKE):45°
Valve seat angle (EXHAUST):45°
Valve steam diameter (INTAKE):6.982-7.000 mm (0.2749-0.2756 in)
Valve steam diameter (EXHAUST):6.970-6.988 mm (0.2744-0.2751 in)
Valve lift minimal (INTAKE):8.500 mm (0.3346 in.)
Valve lift minimal (EXHAUST):8.500 mm (0.3346 in.)
Camshaft journal diameter:19.948-19.960 mm (0.7854-0.7858 in)

Tightening torque specs

Tightening torque specs
Intake manifold mounting (torque in 2 increments) Step 1: 7.4 Nm (0.75 kg·m; 5.5 ft·lb)
Step 2: 9.9 Nm (1.00 kg·m; 7.3 ft·lb)
Cylinder head bolt (torque in 2 increments) Step 1: 22.6 Nm (2.31 kg·m; 16.7 ft·lb)
Step 2: 41.8 Nm (4.26 kg·m; 30.8 ft·lb)
Rocker arm stud11.3 Nm (1.2 kgf·m; 8.3 ft·lb)
Rocker arm adjuster setscrew7.9 Nm (0.8 kgf·m; 5.8 ft·lb)
Connecting rod cap Black Coating: 11.3 Nm (1.2 kgf·m; 8.3 ft·lb)
Gray Metallic Coating: 13.6 Nm (1.4 kgf·m; 10.0 ft·lb)
Flywheel retaining screw74.5 Nm (7.6 kgf·m; 55.0 ft·lb)
Governor lever nut6.8 Nm (0.7 kgf·m; 5.0 ft·lb)
Oil drain plug13.6 Nm (1.4 kgf·m; 10.0 ft·lb)
Spark plug27.0 Nm (2.75 kg·m; 20.0 ft·lb)

Service Data

Engine
Maximum speed:3600±50 rpm
Idle speed:1200±75 rpm
Compression pressure
Standard:1.1 MPa (160 psi)
Compression differential limit between cylinders:15% and less
Oil system
Lubrication system:Full pressure
Oil type:API SG, SH, SJ, or higher
Recommended oil:SAE 10W-30
Oil capacity: W/o oil filter: 1.7 L (1.8 US. qt, 1.5 Imp. qt.)
With oil filter: 1.9 L (2.0 US.qts, 1.7 Imp. qts)
Fuel system
Type:Carburetor with fixed main jet (Walbro or Keihin)
Fuel pump:Pulse type
Fuel filter:In-line
Ignition system
Type:Electronic ignition system
Spark plug:Champion RC12YC
Spark plug gap:0.76 mm (0.030 in)
Ignition coil air gap0.203-0.305 mm (0.008-0.012 in)

References

1. Kohler Confidant ZT710-ZT740 service manual. Kohler Co. 2021.

Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.

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