The Kohler K91 is a 145 cc (8.86 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine from K-series, manufactured by Kohler Co.
The Kohler K91 engine has an L-head (side valve) design and horizontal PTO-shaft. This engine can be equipped with Kohler or Walbro carburetor and magneto, battery or breakerless ignition systems. The K91 engine used paper air cleaner (oiled foam precleaner was available as an option).
The cylinder bore is 60.33 mm (2.38 in) and the piston stroke is 50.80 mm (2 in). This engine produced 4.1 PS (3.0 kW; 4.0 HP) at 4,000 rpm of horsepower.
The breakdown of the engine code is as follows:
- K – K-series
- 9 – Approximate daisplacement (cu·in)
- 1 – Single cylinder
- Suffix (engine is available with the following options):
S – Electric starter;
T – Retractable starter;
ST – Electric and retractable starter;
EP – Electric plant;
A – Special oil pan;
C – Clutch model;
G – Generator applications;
P – Pump model;
Q – Quled model;
R – Reduction gear;
General information
| Engine Specifications | |
| Model | K91 |
| Type | 4-stroke, L-head, single cylinder |
| Displacement | 145 cm 3 (8.86 cu-in) |
| Max. horsepower | 4.1 PS (3.0 kW; 4.0 HP) at 4,000 rpm |
| Max. torque (crank PTO) | – |
| Fuel system | Carburetor (Kohler or Walbro, fixed main jet or adjustable main jet) |
| Cooling system | Forced-air |
| Ignition system | Magneto or battery or breakerless ignition system |
| Lubricating system | Splash type |
| Starting system | Recoil or electric starter |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Fuel tank capacity | – |
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | – | |
| Bore x Stroke | 60.33 X 50.80 mm (2.375 x 2.000 in) | |
| Sleeve internal diameter | 60.312-60.337 mm (2.3745-2.3755 in) | |
| Piston skirt outer diameter | 60.172-60.223 mm (2.369-2.371 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Ring end gap | Top | 0.177-0.432 mm (0.007-0.017 in) |
| Second | 0.177-0.432 mm (0.007-0.017 in) | |
| Connecting rod small end ID | 14.300 mm (0.563 in) | |
| Piston pin outer diameter | 14.282-14.287 mm (0.5623-0.5625 in) | |
| Cylinder Head | ||
| Valve Arrangement: | L-head (sidevalve) | |
| Valves: | 2 | |
| Valve head diameter: | INTAKE | 24.866-25.120 mm (0.979-0.989 in) |
| EXHAUST | 20.498-20.752 mm (0.807-0.817 in) | |
| Stem outer diameter (standard): | INTAKE | 6.299-6.312 mm (0.248-0.2485 in) |
| EXHAUST | 6.248-6.261 mm (0.246-0.2465 in) | |
Tightening torque specs
| Tightening torque specs | |
| Cylinder head bolt | 23 Nm; 2.3 kg·m; 17 ft·lb |
| Flywheel |
Nut: 55-68 Nm; 5.5-6.9 kg·m; 40-50 ft·lb Screw: 28 Nm; 2.9 kg·m; 21 ft·lb |
| Spark plug | 25-30 Nm; 2.55-3.06 kg·m; 18-22 ft·lb |
Service Information
| Engine | |
| Max speed | 4,000 rpm |
| Valve clearance | |
| Intake valve clearance | 0.13-0.23 mm (0.0051-0.0091 in) |
| Exhaust valve clearance | 0.28-0.38 mm (0.011-0.015 in) |
| Oil system | |
| Oil type | API SF or SG |
| Recommended oil |
Summer: SAE 30W Winter: SAE 5W-20, 5W-30 |
| Oil capacity | 0.7 L (0.74 US. qt, 0.62 Imp. qt.) |
| Ignition system | |
| Spark plug | Champion: RJ8C |
| Spark plug gap | 0.65 mm (0.0256 in) |
Author:
I have a k-91 and don’t know the gap for points, could you help me?
Thanks
.02″