The Kohler ECH680 is a 694 cc (42.4 cu·in) natural aspirated V-twin four-stroke air-cooled internal combustion small gasoline engine from the Command PRO EFI series with a horizontal shaft, manufactured by Kohler Co for general-purpose applications.
A 80.0 mm (3.15 in) cylinder bore and 69.0 mm (2.72 in) piston stroke give the ECH680 engine a total of 694 cc of displacement. The compression ratio rating is 8.7:1.
The ECH680 engine produces 23.4 PS (17.2 KW; 23.0 HP) at 3,600 rpm of maximum horsepower and 49.2 Nm (5.00 kg·m; 36.30 ft·lb) at 2,800 rpm of peak torque.
The Kohler ECH680 features:
- OHV (overhead valve) design
- Hydraulic valve lifters
- Aluminum cylinder block
- Cast iron cylinder liners
- Hardened crank journals
- PTO thrust bearing
- Electronic ignition system
- Electronic fuel injection system (EFI)
- Full pressure lubrication system
- Oil cooler
- Spin-on, full-flow oil filter
- Forced air cooling system
- Solenoid shift starter
- 20 amp charging, regulated
General information
| Engine Specifications | |
| Engine model | Command PRO EFI ECH680 |
| Engine type | 4-stroke, OHV, V-twin |
| Displacement | 694 cm3, (42.4 cu·in) |
| Max. horsepower | 23.4 PS (17.2 KW; 23.0 HP) at 3,600 rpm |
| Max. torque | 49.2 Nm (5.00 kg·m; 36.30 ft·lb) at 2,800 rpm |
| Cooling system | Forced air |
| Air cleaner | High-efficiency, heavy-duty air filters |
| Lubricating system | Full pressure |
| Ignition system | Electronic ignition system |
| Fuel system | EFI (electronic fuel injection) system |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Starting system | Electric starter |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
| Dimensions (L x W X H) | 376 x 480 x 622 mm (14.8 x 18.9 x 24.5 in) |
| Dry weight | 49.0 kg (108.0 lbs) |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | 8.7:1 |
| Cylinder bore: | 80.0 mm (3.15 in) |
| Piston stroke: | 69.0 mm (2.72 in) |
| Cylinder internal diameter (standard): | 80.000-80.025 mm (3.1496-3.1506 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Piston style A | |
| Thrust face outer diameter (standard): | 79.943-79.961 mm (3.1473-3.1480 in) |
| Piston pin diameter: | 16.995-17.000 mm (0.6691-0.6693 in) |
| Side clearance (Top): | 0.050-0.095 mm (0.0019-0.0037 in) |
| Side clearance (Second): | 0.030-0.075 mm (0.0012-0.00307 in) |
| Side clearance (Oil): | 0.010-0.110 mm (0.0004-0.0043 in) |
| Ring end gap (Top): | 0.250-0.560 mm (0.0100-0.0224 in) |
| Ring end gap (Second): | 0.250-0.560 mm (0.0100-0.0224 in) |
| Piston style B | |
| Thrust face outer diameter (standard): | 79.966 mm (3.1483 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 | |
| Number of main bearings: | 2 |
| 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 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): | 8.07 mm (0.3177 in) |
| Valve lift minimal (EXHAUST): | 8.07 mm (0.3177 in) |
| Camshaft journal diameter : | 19.962-19.975 mm (0.7859-0.7864 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 lb·ft) Step 2: 9.9 Nm (1.00 kg·m; 7.3 lb·ft) |
| Connecting rod cap fastener | Black Coating: 11.6 Nm (1.2 kgf·m; 8.6 lb·ft) Gray Metallic Coating: 13.6 Nm (1.4 kgf·m; 10.0 lb·ft) |
| Cylinder head | Nut (torque in 2 increments): Step 1: 16.9 Nm (1.72 kg·m; 12.5 lb·ft) Step 2: 35.5 Nm (3.62 kg·m; 26.2 lb·ft) Bolt (torque in 2 increments) Step 1: 22.6 Nm (2.31 kg·m; 16.7 lb·ft) Step 2: 41.8 Nm (4.26 kg·m; 30.8 lb·ft) |
| Fan | 9.9 Nm (1.0 kg·m; 7.3 lb·ft) |
| Flywheel | 71.6 Nm (7.3 kgf·m; 52.8 lb·ft) |
| Muffler retaining nuts | 27.8 Nm (2.8 kgf·m; 20.5 lb·ft) |
| Spark plug | 27 Nm (2.75 kg·m; 20.0 lb·ft) |
Service Data
| Engine | |
| Maximum speed: | 3600±50 rpm |
| Idle speed: | 1200±75 rpm |
| Oil system | |
| Lubrication system: | Full pressure |
| Oil type: | API SJ, or higher |
| Recommended oil: | SAE 10W-30, Kohler PRO 10W-50 |
| 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) |
| Ignition system | |
| Type: | Electronic ignition system |
| Spark plug: | Champion RC12YC or Champion XC12YC |
| Spark plug gap: | 0.76 mm (0.030 in) |
| Ignition coil air gap | 0.280-0.330 mm (0.011-0.013 in) |
References
1. Kohler Command PRO EFI ECH630-ECH749, CH735, CH26, CH745 service manual. Kohler Co. 2023.
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