The Kohler LH685 is a 674 cc, (41.1 cu·in) V-twin liquid-cooled four-stroke internal combustion gasoline engine from the Aegis series, manufactured by Kohler Co.
The Kohler LH685 engine has an OHV (overhead valve) design, horizontal PTO-shaft, pressurized lubrication system with oil pump. This engine is equipped with a one-barrel carburetor (Keihin) with a fixed main jet and electronic ignition system.
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 horsepower and 54.3 Nm (5.54 kg·m; 40.07 ft·lb) at 2,200 rpm of peak torque.
The breakdown of the engine code is as follows:
- L – Liquid-cooled
- H – Horizontal PTO shaft
- 685 – Numerical designation
General information
| Engine Specifications | |
| Model | AEGIS LH685 |
| Type | 4-stroke, OHV, V-twin |
| Displacement | 674 cm 3 (41.1 cu-in) |
| Max. horsepower | 25.3 PS (18.6 KW; 25.0 HP) at 3,600 rpm |
| Max. torque | 54.3 Nm (5.54 kg·m; 40.07 ft·lb) at 2,200 rpm |
| Fuel system | One-barrel carburetor with a fixed main jet (Keihin) |
| Cooling system | Liquid-cooled |
| Ignition system | Electronic ignition system |
| Lubricating system | Pressurized lubrication |
| Starting system | Electric starter |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | 8.5:1 | |
| Bore x Stroke | 80.0 X 67.0 mm (3.15 x 2.64 in) | |
| Sleeve internal diameter | 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 | 79.963-79.981 mm (3.1481-3.1488 in) | |
| Connecting rod small end ID | 17.006-17.013 mm (0.6695-0.6698 in) | |
| Piston pin outer diameter | 16.995-17.000 mm (0.6691-0.6693 in) | |
| Side clearance: | Top | 0.050-0.096 mm (0.0020-0.0038 in) |
| Second | 0.030-0.076 mm (0.0012-0.0030 in) | |
| 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) |
| Second | 0.250-0.460 mm (0.0098-0.0181 in) | |
| Piston type B | ||
| Piston skirt outer diameter | 79.966 mm (3.1483 in) | |
| Connecting rod small end ID | 17.006-17.013 mm (0.6695-0.6698 in) | |
| Piston pin outer diameter | 16.995-17.000 mm (0.6691-0.6693 in) | |
| Side clearance: | Top | 0.030-0.070 mm (0.0010-0.0026 in) |
| Second | 0.030-0.070 mm (0.0010-0.0026 in) | |
| 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) |
| Second | 1.400-1.679 mm (0.0551-0.0661 in) | |
| 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) | |
| Cylinder Head | ||
| Valve Arrangement: | OHV, gear drive | |
| Valves: | 4 (2 per cylinder) | |
| Valve head diameter: | INTAKE | 33.370-33.630 mm (1.3138-1.324 in) |
| EXHAUST | 29.370-29.630 mm (1.1563-1.1665 in) | |
| Stem outer diameter: | INTAKE | 6.982-7.000 mm (0.2749-0.2756 in) |
| EXHAUST | 6.970-6.988 mm (0.2744-0.2751 in) | |
Tightening torque specs
| Tightening torque specs | |
| Cylinder head bolt |
Step 1: 16.9 Nm (1.72 kg·m; 12.47 ft·lb) Step 2: 33.9 Nm (3.46 kg·m; 25.02 ft·lb) |
| Flywheel | 66.4 Nm (6.77 kg·m; 49.0 ft·lb) |
| Spark plug | 27 Nm (2.75 kg·m; 20.0 ft·lb) |
Service Information
| Oil system | |
| Oil type | API SG, SH, SJ, or higher |
| Recommended oil | SAE 10W-30 |
| 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) |
| Cooling system | |
| Type | Pressurized cooling system with integrated belt-driven water pump |
| Coolant capacity | 2.0 liters (2.1 US.qts, 1.8 Imp. qts) |
| Ignition system | |
| Spark plug | Champion RC14YC |
| Spark plug gap | 0.76 mm (0.030 in) |
| Ignition module air gap | 0.2-0.3 mm (0.008-0.012 in) |
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