Tecumseh HH100

Tecumseh HH100The Tecumseh HH100 is a 389 cc (23.7 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine, manufactured by Tecumseh.

The Tecumseh HH100 engine has an L-head (side valve) design, horizontal PTO shaft, cast-iron cylinder block, and cast-iron cylinder head. This engine can be equipped with Tecumseh or Walbro carburetor and solid-state ignition system (CDI).

The cylinder bore is 84.1 mm (3.31 in) and the piston stroke is 69.8 mm (2.75 in). This engine produced 10.2 PS (7.5 kW; 10.0 HP) of horsepower.

The breakdown of the engine code is as follows:

  • HH – Horizontal-Heavy Duty
  • 100 – 10.0 HP

General information

Engine Specifications
Model HH100
Type 4-stroke, L-head, single cylinder
Displacement 389 cm3 (23.7 cu-in)
Max. horsepower 10.2 PS (7.5 kW; 10.0 HP)
Max. torque (crank PTO)
Fuel system Carburetor (Tecumseh or Walbro)
Cooling system Forced-air
Ignition system Solid-state ignition system (CDI)
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
Bore x Stroke 84.1 X 69.8 mm (3.31 x 2.75 in)
Sleeve internal diameter 84.125-84.150 mm (3.312-3.313 in)
Piston skirt outer diameter 84.023-84.074 mm (3.308-3.31 in)
Number of piston rings (compression / oil): 2 / 1
Ring end gap Top 0.178-0.508 mm (0.007-0.02 in)
Second 0.178-0.508 mm (0.007-0.02 in)
Piston pin outer diameter 17.457-17.463 mm (0.6873-0.6875 in)
Cylinder Head
Valve Arrangement: L-head (sidevalve)
Valves: 2
Valve spring free length: 47.879 mm (1.885 in)
Camshaft lobe diameter: 33.134-33.236 mm (1.3045-1.3085 in)

Tightening torque specs

Tightening torque specs
Cylinder head bolt 20.3-27.1 Nm; 2.07-2.76 kg·m; 15-20 ft·lb
Flywheel nut 67.8-74.6 Nm; 6.9-7.6 kg·m; 50-55 ft·lb
Spark plug 25-30 Nm; 2.55-3.06 kg·m; 18-22 ft·lb

Service Information

Valve clearance
Intake valve clearance 0.254 mm (0.010 in)
Exhaust valve clearance 0.508 mm (0.020 in)
Oil system
Oil type API SF, SJ
Recommended oil SAE 30, 10-W30
Oil capacity 1.4 liters (1.5 US.qts, 1.23 Imp. qts)
Ignition system
Spark plug Champion J-8
Spark plug gap 0.763 mm (0.03 in)
Fuel system
Type Carburetor (Tecumseh or Walbro)
Main adjustment screw Tecumseh: 1-3/4 turns
Walbro: 1-1/2 turns off seat
Idle adjustment screw Tecumseh: 1-1/4 turns
Walbro: 1-1/4 turns off seat
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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  1. Do have a pin and seat kit for LME 29 Walbro Carburetor .
    And an after market carburetor.
    For Sears 10xl 1971 riding mower.
    A Service Main Nozzle, under cut.
    Fixed High speed nut and pin
    Float damper spring

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