Briggs and Stratton 40G777

Briggs and Stratton 40G777The Briggs and Stratton 40G777 Professional Series is a 656 cc, (40.0 cu·in) natural aspirated two-cylinders four-stroke air-cooled internal combustion gasoline engine with a vertical shaft, for general-purpose applications.

Cylinder bore and piston stroke are 75.44 mm (2.97 in) and 73.40 mm (2.89 in), respectively. This engine produced 20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm of horsepower.

The B&S 40G777 features:

  • OHV design
  • Electronic ignition system
  • Float type carburetor
  • Centrifugal governor
  • Full pressure lubrication system with spin-on oil filter
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine model B&S 40G777 Professional Series
Engine type 4-stroke, OHV, V-twin
Displacement 656 cm3, (40.0 cu·in)
Max. horsepower 20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm
Max. torque
Cooling system Forced air
Air cleaner Dual-Clean (paper cartridge with a foam pre-cleaner)
Lubricating system Full pressure lubrication with spin-on oil filter
Ignition system Electronic
Fuel system Float type carburetor
Fuel used Unleaded gasoline (octane number 86 or higher)
Starting system Electric starter
Governor Centrifugal governor
Charging system Alternator 12V
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Compression ratio:
Cylinder bore: 75.44 mm (2.97 in)
Piston stroke: 73.40 mm (2.89 in)
Number of piston rings (compression / oil): 2/1
Cylinder head
Valve arrangement: OHV
Valves: 2 (4 valves in total)

Service Data

Valve clearance
Intake valve clearance: 0.10-0.15 mm (0.004-0.006 in)
Exhaust valve clearance: 0.10-0.15 mm (0.004-0.006 in)
Oil system
Lubrication system: Full pressure lubrication system with spin-on oil filter
Oil type: API SF, SG, SH, SJ or higher
Recommended oil: SAE 5W-30, 10W-30
Oil capacity: W/o oil filter: 1.8 liters (1.9 US.qts, 1.58 Imp. qts)
With oil filter: 1.9 liters (2.01 US.qts, 1.67 Imp. qts)
Fuel system
Type: Float type carburetor
Ignition system
Type: Electronic
Spark plug: Resistor spark plug:
Briggs and Stratton 491055
Champion RC12YC
Long life platinum spark plug:
Briggs and Stratton 5066
Spark plug gap: 0.7-0.8 mm (0.0276-0.0315 in)
Spark plug torque: 20.0 Nm (2.04 kg·m; 14.76 ft·lb)
Armature air gap 0.20-0.30 mm (0.008-0.012 in)


Manufacturer or Brand Models
Lawn tractors
Craftsman 107.25004
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.

Be the first to comment

Leave a Reply

Your email address will not be published.