Briggs and Stratton 49M877

Briggs and Stratton 49M877The Briggs and Stratton 49M877 Professional Series is a 810 cc, (49.4 cu·in) natural aspirated two-cylinders four-stroke air-cooled internal combustion gasoline engine with a vertical shaft, for general-purpose applications.

A 83.81 mm (3.3 in) cylinder bore and 73.41 mm (2.89 in) piston stroke give the 49M877 engine a total of 810 cc of displacement. This engine produced 30.5 PS (22.4 kW; 30.0 HP) at 3,600 rpm of horsepower.

The B&S 49M877 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 modelB&S 49M877 Professional Series
Engine type4-stroke, OHV, V-twin
Displacement810 cm3, (49.4 cu·in)
Max. horsepower30.5 PS (22.4 kW; 30.0 HP) at 3,600 rpm
Max. torque
Cooling systemForced air
Air cleanerDual-Clean (paper cartridge with a foam pre-cleaner)
Lubricating systemFull pressure lubrication with spin-on oil filter
Ignition systemElectronic
Fuel systemFloat type carburetor
Fuel usedUnleaded gasoline (octane number 86 or higher)
Starting systemElectric starter
GovernorCentrifugal governor
Charging systemAlternator 12V
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Compression ratio:
Cylinder bore:79.24 mm (3.12 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: 1.9 liters (2.01 US.qts, 1.67 Imp. qts)
With oil filter: 2.0 liters (2.11 US.qts, 1.76 Imp. qts)
Fuel system
Type:Float type carburetor
Ignition system
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 gap0.20-0.30 mm (0.008-0.012 in)


Manufacturer or BrandModels
Lawn tractors
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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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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