Briggs and Stratton 386777

Briggs and Stratton 386777The Briggs and Stratton 386777 Vanguard is a 627 cc (38.2 cu·in) V-twin air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.

The B&S 386777 engine has an OHV (overhead valve) design and a vertical PTO shaft. This engine is equipped with float type, side-draft carburetor and an electronic ignition system. The B&S 386777 engine used Dual-Clean air cleaner (paper element with a foam pre-cleaner).

The cylinder bore is 75.5 mm (2.97 in) and the piston stroke is 70.0 mm (2.75 in). This engine produced 23.3 PS (17.1 KW; 23.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

  • 38 – Displacement
  • 6 – Basic design series
  • 7 – Vertical PTO-shaft
  • 7 – Plain bearing, Pressure lubrication
  • 7 – Electric starter

General information

Engine Specifications
ModelB&S 386777 Vanguard
Type4-stroke, OHV, V-twin
Displacement627 cm 3 (38.2 cu-in)
Max. horsepower23.3 PS (17.1 KW; 23.0 HP) at 3,600 rpm
Max. torque
Fuel systemFloat type, side-draft carburetor
Cooling systemForced-air
Ignition systemElectronic
Lubricating systemPressure lubrication, oil cooler
Starting systemElectric starter
Fuel usedGasoline
Fuel tank capacity

Cylinder Block and Head

Cylinder block
Bore x Stroke75.5 mm X 70.0 mm (2.97 x 2.76 in)
Sleeve internal diameter75.500-75.520 mm (2.9724-2.9730 in)
Number of piston rings (compression / oil):2 / 1
Side clearanceTop0.045-0.076 mm (0.0018-0.003 in)
Second0.045-0.076 mm (0.0018-0.003 in)
Oil0.110-0.150 mm (0.0043-0.0059 in)
Ring end gapTop0.200-0.400 mm (0.0079-0.0157 in)
Second0.200-0.400 mm (0.0079-0.0157 in)
Oil0.200-0.400 mm (0.0079-0.0157 in)
Connecting rod small end ID18.040-18.050 mm (0.7100-0.7105 in)
Piston pin outer diameter18.000-18.010 mm (0.7085-0.7090 in)
Cylinder Head
Valve Arrangement:OHV
Valves:4 (2 per cylinder)
Valve steam diameterINTAKE5.950-5.960 mm (0.2343-0.2346 in)
EXHAUST5.940-5.950 mm (0.2339-0.2343 in)

Tightening torque

Tightening torque specs
Alternator (to cylinder)2.0 Nm; 1.5 ft·lb
Air cleaner base (to carburetor)7.0 Nm; 5.2 ft·lb
Air cleaner support bracket7.0 Nm; 5.2 ft·lb
Armature3.0 Nm; 2.2 ft·lb
Blower housings7.0 Nm; 5.2 ft·lb
Back plate7.0 Nm; 5.2 ft·lb
Breather3.0 Nm; 2.2 ft·lb
Carburetor to manifold7.0 Nm; 5.2 ft·lb
Connecting rod13.0 Nm; 6.9 ft·lb
Crankcase cover17.0 Nm; 12.6 ft·lb
Cylinder head19.0 Nm; 14.1 ft·lb
Cylinder shield7.0 Nm; 5.2 ft·lb
Exhaust manifold17.0 Nm; 12.6 ft·lb
Flywheel nut175.0 Nm; 129.6 ft·lb
Fan Retainer17.0 Nm; 12.6 ft·lb
Governor lever nut8.0 Nm; 5.9 ft·lb
Governor control bracket16.0 Nm; 11.9 ft·lb
Intake manifold to cylinder head16.0 Nm; 11.9 ft·lb
Oil pump7.0 Nm; 5.2 ft·lb
Rewind starter (to blower housing)7.0 Nm; 5.2 ft·lb
Rocker arm lock nut7.0 Nm; 5.2 ft·lb
Rocker arm stud11.0 Nm; 8.2 ft·lb
Starter motor16.0 Nm; 11.9 ft·lb
Starter motor thru bolts6.0 Nm; 4.4 ft·lb
Valve cover3.0 Nm; 2.2 ft·lb

Service Information

Max speed3,600 rpm
Valve clearance
Intake valve clearance0.10-0.15 mm (0.004-0.006 in)
Exhaust valve clearance0.10-0.15 mm (0.004-0.006 in)
Oil system
Oil typeAPI SF, SG, SH, SJ or higher
Recommended oil Summer: SAE 30, 10W-30
Winter: SAE 5W-30
Oil capacity (with filter)1.65 L (1.74 US. qt, 1.45 Imp. qt.)
Ignition system
Spark plugChampion RC12YC
Spark plug gap0.7-0.8 mm (0.0276-0.0315 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 site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.


  1. hello
    great site! I am searching for the engine torque spec for a vanguard 3867 engine but cannot find it detailed anywhere, do you know where i can find it? and why its not detailed as it I want compare motors

  2. Looking for a complete engine overhaul kit. Where is the best place to purchase this from? briggs & stratton vanguard 23 hp commercial, Model:386777, Type:0114-E1, Code:06062011

Leave a Reply

Your email address will not be published.