Kohler LH685

Kohler LH685The Kohler LH685 is a 674 cc (41.1 cu·in) natural aspirated V-twin four-stroke liquid-cooled internal combustion small gasoline engine with a horizontal shaft from the Aegis series, manufactured by Kohler Co for general-purpose applications.

It has an 80.0 mm (3.15 in) cylinder bore and 67.0 mm (2.64 in) piston stroke. The compression ratio rating is 8.5:1.

This engine produced 25.3 PS (18.6 KW; 25.0 HP) at 3,600 rpm of maximum horsepower and 54.3 Nm (5.54 kg·m; 40.07 ft·lb) at 2,200 rpm of peak torque.

The Kohler Aegis LH685 features:

  • OHV (overhead valve) design
  • Hydraulic valve system
  • Electronic ignition system
  • One-barrel carburetor with fixed main jet (Keihin)
  • Centrifugal flyweight mechanical governor
  • Full pressure with Gerotor oil pump lubrication system
  • Liquid-cooled cooling system with parallel-flow radiator and integrated belt-driven water pump
  • Solenoid shift starter (12V)

General information

Engine Specifications
Engine modelAegis LH685
Engine type4-stroke, OHV, V-twin
Displacement674 cm3, (41.1 cu·in)
Max. horsepower25.3 PS (18.6 KW; 25.0 HP) at 3,600 rpm
Max. torque54.3 Nm (5.54 kg·m; 40.07 ft·lb) at 2,200 rpm
Cooling systemLiquid-cooled
Air cleanerHeavy-Duty air cleaner
Lubricating systemFull pressure with gerotor oil pump
Ignition systemElectronic ignition system
Fuel systemCarburetor with fixed main jet (Keihin)
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemSolenoid shift starter (12V)
Charging system20A charging, regulated
GovernorCentrifugal flyweight mechanical governor
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)432 x 459 x 674 mm (17.0 x 18.1 x 26.5 in)
Dry weight51.7 kg (114.0 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:8.5:1
Cylinder bore:80.0 mm (3.15 in)
Piston stroke:67.0 mm (2.64 in)
Cylinder internal diameter (standard):80.000-80.025 mm (3.1496-3.1506 in)
Number of piston rings (compression / oil):2/1
Piston type A
Piston skirt outer diameter (standard):79.963-79.981 mm (3.1481-3.1488 in)
Connecting rod small end diameter (standard):17.006-17.013 mm (0.6695-0.6698 in)
Piston pin diameter:16.995-17.000 mm (0.6691-0.6693 in)
Side clearance (Top):0.050-0.096 mm (0.0020-0.0038 in)
Side clearance (Second):0.030-0.076 mm (0.0012-0.0030 in)
Side clearance (Oil):0.046-0.196 mm (0.0018-0.0077 in)
Ring end gap (Top):0.180-0.430 mm (0.0071-0.0169 in)
Ring end gap (Second):0.250-0.460 mm (0.0098-0.0181 in)
Piston type B
Piston skirt outer diameter (standard):79.966 mm (3.1483 in)
Connecting rod small end diameter (standard):17.006-17.013 mm (0.6695-0.6698 in)
Piston pin diameter:16.995-17.000 mm (0.6691-0.6693 in)
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):0.100-0.279 mm (0.0039-0.0110 in)
Ring end gap (Second):1.400-1.679 mm (0.0551-0.0661 in)
Crankshaft
Crankshaft main journal diameter:40.913-40.935 mm (1.6107-1.6116 in)
Crankpin journal diameter:35.955-35.973 mm (1.4155-1.4163 in)
Crankshaft center distance:33.5 mm (1.32 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 face angle (INTAKE):45°
Valve face angle (EXHAUST):45°
Seat angle (INTAKE):89°
Seat angle (EXHAUST):89°
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 (min) (INTAKE):8.88 mm (0.3496 in)
Valve lift (min) (EXHAUST):8.88 mm (0.3496 in)
Camshaft journal diameter :19.962-19.975 mm (0.7859-0.7864 in)

Tightening torque specs

Tightening torque specs
Intake manifold (torque in 2 increments) Step 1: 7.4 Nm (0.8 kgf·m; 5.5 lb·ft)
Step 2: 9.9 Nm (1.0 kgf·m; 7.3 lb·ft)
Carburetor mounting9.9 Nm (1.0 kgf·m; 7.3 lb·ft)
Connecting rod cap11.3 Nm (1.15 kg·m; 8.3 ft·lb)
Oil drain plugs13.6 Nm (1.4 kg·m; 10.0 ft·lb)
Cylinder head (torque in 2 increments) Step 1: 16.9 Nm (1.7 kg·m; 12.5 ft·lb)
Step 2: 33.9 Nm (3.5 kg·m; 25.0 ft·lb)
Rocker pivot11.3 Nm (1.1 kg·m; 8.34 ft·lb)
Rear fan shaft to mounting bracket nut15.8 Nm (1.6 kgf·m; 11.7 lb·ft)
Front fan assembly to fan shaft nut15.8 Nm (1.6 kgf·m; 11.7 lb·ft)
Flywheel66.4 Nm (6.77 kg·m; 49 ft·lb)
Spark plug27 Nm (2.75 kg·m; 19.93 ft·lb)
Muffler retaining nuts24.4 Nm (2.5 kg·m; 18.0 ft·lb)
Valve cover6.2 Nm (0.63 kg·m; 4.6 ft·lb)
Governor lever nut6.8 Nm (0.7 kgf·m; 5.0 lb·ft)

Service Data

Engine
Idle speed:1200±75 rpm
Compression pressure
Compression differential limit between cylinders:15% and less
Oil system
Lubrication system:Full pressure with gerotor oil pump
Oil type:SAE 10W-30
Recommended oil:API SG, SH, SJ, or higher
Oil capacity: W/o oil filter: 1.6 liters (1.7 US.qts, 1.4 Imp. qts)
With oil filter: 1.8 liters (1.9 US.qts, 1.58 Imp. qts)
Ignition system
Type:Electronic ignition system
Spark plug:Champion RC14YC or Kohler 6613201-S
Spark plug gap:0.76 mm (0.030 in)
Spark plug torque:27 N·m (2.8 kg·m, 19.9 ft·lb)
Ignition module air gap:0.20-0.30 mm (0.008-0.012 in)
Cooling system
Cooling system:Liquid-cooled cooling system with parallel-flow radiator and integrated belt-driven water pump
Coolant capacity:2.0 liters (2.1 US.qts, 1.8 Imp. qts)

References

1. Kohler Aegis LH630, LH640, LH685, LH690, LH750, LH755 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.

ATTENTION! Dear visitors, this is an informational database of technical specifications, we are not a parts supplier or a marketplace.

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.

Be the first to comment

Leave a Reply

Your email address will not be published.


*