Simplicity Sovereign 18H

Simplicity Sovereign 18HThe Simplicity Sovereign 18H is a garden tractor model from the Sovereign series, manufactured from 1993 to 2000 by Simplicity in Port Washington, Wisconsin, USA. It was available in two-wheel drive (2WD) version.

The Simplicity Sovereign 18H is equipped with a 624 cc (38.1 cu·in) two-cylinder gasoline engine with 77.0 mm (3.03 in) of the cylinder bore and 67.0 mm (2.64 in) of the piston stroke, and a belt-driven hydrostatic transmission with infinite forward and reverse gears.

The Simplicity Sovereign 18H garden tractor features:

  • The Kohler CH18 gasoline engine which produces 18.2 PS (13.4 kW; 18.0 HP) at 3,600 rpm of horsepower
  • Manual or power (optional) steering
  • Mechanical band brakes
  • Open operator station
  • Sleeve hitch (optional)
  • Independent middle PTO with manual clutch
  • 11.4 liters (3.0 US gal.; 2.5 Imp. gal)

General specifications

General Specifications
ModelSimplicity Sovereign 18H
Tractor typeGarden tractor
Production years1993-2000
FactoryPort Washington, Wisconsin, USA
Dimensions and weight
Length1,770 mm (69.7 in)
Width930 mm (36.6 in)
Height (steering wheel)1,000 mm (39.4 in)
Wheel base1,280 mm (50.4 in)
Weight312 kg (688 lbs)
Fuel capacity
Fuel tank capacity11.4 liters (3 US gal.; 2.5 Imp. gal)


Engine modelKohler Command PRO CH18S
Engine type4-stroke, OHV, V-twin
Displacement624 cm 3 (38.0 cu-in)
Compression ratio:8.5:1
Cylinder bore:77.0 mm (3.03 in)
Piston stroke:67.0 mm (2.64 in)
Max. horsepower18.2 PS (13.4 KW; 18.0 HP) at 3,600 rpm
Max. torque43.6 Nm (4.45 kg·m; 32.2 ft·lb) at 2,200 rpm
Cooling systemForced air
Air cleanerReplaceable, paper element
Lubricating systemFull pressure
Ignition systemElectronic ignition
Fuel systemCarburetor with fixed main jet
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemElectric starter
GovernorMechanical centrifugal governor
PTO shaft rotationCounterclockwise (from PTO shaft side)
Dimensions (L x W X H)355 x 451 x 483 mm (14.0 x 17.7 x 19.0 in)
Dry weight41.0 kg (90.0 lbs)
Compression pressure
Standard:1.1 MPa (160 psi)
Compression differential limit between cylinders:15% and less
Oil system
Oil type:API SG, SH, SJ, or higher
Recommended oil:SAE 10W-30
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)
Fuel system
Fuel pump:Pulse type
Fuel filter:In-line
Ignition system
Spark plug:Champion RC12YC
Spark plug gap:0.76 mm (0.030 in)
Ignition coil air gap0.280-0.330 mm (0.011-0.013 in)

Transmission and chassis

Chassis, steering and brakes
Steering typeManual or power (optional)
BrakesMechanical band brakes
Transmission manufacturer or model
Transmission typeBelt-driven hydrostatic
GearsInfinite forward and reverse
Speed Forward: 11.3 kmh (7.0 mph)
Reverse: 6.4 kmh (4.0 mph)


Front tires Lawn/turf: 16×6.50-8
Rear tires Lawn/turf: 23×10.5-12

Rear Hitch

Three-Point Hitch
CategorySleeve hitch (optional)
Control type
Lift capacity (at ends)

PTO (Power take-off shaft)

Middle PTO typeIndependent with manual clutch
Middle PTO speed

Electrical system

Electrical system
Charging system
Charging amps


Simplicity 1691218: 42″ mid-mount mower deck with 3-blade
Cutting width1,060 mm (42.0 in)
Total width1,420 mm (56.0 in)
Cut height30-70 mm (1.5-3.1 in)
Weight57 kg (127 lbs)
Simplicity 1691219: 48″ mid-mount mower deck with 3-blade
Cutting width1,210 mm (48.0 in)
Total width1,570 mm (62.0 in)
Cut height30-70 mm (1.5-3.1 in)
Weight59 kg (153 lbs)
Simplicity 1691520: 42″ front-mount blade
Cutting width1,060 mm (42.0 in)
Weight31 kg (70 lbs)
Simplicity 1691521: 36″ front-mount snowblower
Cleaning width910 mm (36.0 in)
Weight59 kg (131 lbs)
Simplicity 1691522: 42″ front-mount snowblower
Cleaning width1,060 mm (42.0 in)
Weight64 kg (143 lbs)
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.

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