Briggs and Stratton 28Q777

Briggs and Stratton 28Q777The Briggs and Stratton 28Q777 is a 465 cc, (28.4 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a vertical shaft, manufactured by Briggs & Stratton for general-purpose applications.

Cylinder bore and piston stroke are 87.3 mm (3.44 in) and 77.7 mm (3.06 in), respectively. The B&S 28Q777 engine produced 15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm of maximum horsepower.

The B&S 28Q777 features:

  • Cast iron sleeve
  • OHV (overhead valve) design
  • Plain bearing
  • Electronic ignition system
  • Float type carburetor
  • Centrifugal governor
  • Full pressure lubrication system
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine model28Q777
Engine type4-stroke, OHV, single-cylinder
Displacement465 cm3, (28.38 cu·in)
Max. horsepower15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm
Max. torque
Cooling systemForced air
Air cleanerPaper filter with a foam pre-cleaner
Lubricating systemFull pressure lubrication system
Ignition systemElectronic
Fuel systemFloat type carburetor
Fuel consumption
Fuel usedGasoline
Starting systemElectric starter
GovernorCentrifugal governor
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Compression ratio:
Cylinder bore:87.3 mm (3.44 in)
Piston stroke:77.7 mm (3.06 in)
Cylinder internal diameter (standard):87.300-87.400 mm (3.437-3.4409 in)
Number of piston rings (compression / oil):2/1
Connecting rod big end diameter (standard):31.760-31.810 mm (1.2504-1.2524 in)
Connecting rod small end diameter (standard):20.330-20.370 mm (0.8004-0.802 in)
Piston pin diameter:20.290-20.310 mm (0.7988-0.7996 in)
Side clearance (Top):0.03-0.07 mm (0.0012-0.0028 in)
Side clearance (Second):0.03-0.07 mm (0.0012-0.0028 in)
Side clearance (Oil):0.03-0.07 mm (0.0012-0.0028 in)
Ring end gap (Top):0.15-0.35 mm (0.0059-0.0138 in)
Ring end gap (Second):0.15-0.35 mm (0.0059-0.0138 in)
Ring end gap (Oil):0.35-0.70 mm (0.0138-0.0276 in)
Crankshaft main journal diameter:34.950 mm (1.376 in)
Crankpin journal diameter:31.690-31.720 mm (1.2476-1.2488 in)
Crankshaft center distance:38.85 mm (1.53 in)
Cylinder head
Valve arrangement:OHV (overhead valve), gear driven
Valves:2
Valve steam diameter (INTAKE):5.960-5.980 mm (0.2346-0.2354 in)
Valve steam diameter (EXHAUST):5.960-5.980 mm (0.2346-0.2354 in)
Camshaft lobe height (INTAKE):21.02 mm (0.8276 in)
Camshaft lobe height (EXHAUST):21.02 mm (0.8276 in)

Tightening torque

Tightening torque specs
Air cleaner base6.0 Nm; 4.4 ft·lb
Alternator2.0 Nm; 1.5 ft·lb
Armature3.0 Nm; 2.2 ft·lb
Blower housings10.0 Nm; 7.4 ft·lb
Blower housing brackets10.0 Nm; 7.4 ft·lb
Breather4.0 Nm; 2.9 ft·lb
Carburetor to intake manifold7.0 Nm; 5.2 ft·lb
Connecting rod21.0 Nm; 15.6 ft·lb
Control bracket5.0 Nm; 3.7 ft·lb
Crankcase cover25.0 Nm; 18.5 ft·lb
Cylinder head25.0 Nm; 18.5 ft·lb
Cylinder shield5.0 Nm; 3.7 ft·lb
Exhaust manifold / adapter19.0 Nm; 14.0 ft·lb
Flywheel nut135.0 Nm; 100.0 ft·lb
Flywheel fan16.0 Nm; 11.9 ft·lb
Fuel pump5.0 Nm; 3.7 ft·lb
Governor lever nut5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head10.0 Nm; 7.4 ft·lb
Muffler19.0 Nm; 14.1 ft·lb
Oil drain plug14.0 Nm; 10.4 ft·lb
Oil pump cover10.0 Nm; 7.4 ft·lb
Starter motor16.0 Nm; 11.9 ft·lb

Service Data

Valve clearance
Intake valve clearance:0.08-0.13 mm (0.0031-0.0051 in)
Exhaust valve clearance:0.13-0.18 mm (0.0051-0.0071 in)
Oil type:SF, SG, SH, SJ or higher
Recommended oil: Summer: SAE 30, 10W-30
Winter: SAE 5W-30
Oil capacity:1.40 L (1.48 US. qt, 1.23 Imp. qt.)
Fuel system
Type:Float type carburetor
Fuel pump:Pulse type
Ignition system
Type:Electronic
Spark plug:Champion RJ19LM
Spark plug gap:0.7-0.8 mm (0.0276-0.0315 in)
Spark plug torque:20 N·m (2 kg·m, 14.7 ft·lb)
Armature air gap0.25-0.36 mm (0.0098-0.0142 in)
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.


*