Briggs and Stratton 331777

Briggs and Stratton 331777The Briggs and Stratton 331777 Intek is a 540 cc (32.9 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.

The B&S 331777 engine has an OHV (overhead) design and a vertical PTO shaft. This engine is equipped with float type carburetor, pulse type fuel pump and an electronic ignition system. The B&S 331777 engine used a paper air filter with a foam pre-cleaner. It is equipped with an electric starter (12V).

The cylinder bore is 94.0 mm (3.7 in) and the piston stroke is 77.8 mm (3.06 in). This engine produced 20.3 PS (14.9 kW; 20.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

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

General information

Engine Specifications
ModelB&S 331777 Intek
Type4-stroke, OHV, single-cylinder
Displacement540 cm 3 (32.9 cu-in)
Max. horsepower20.3 PS (14.9 kW; 20.0 HP) at 3,600 rpm
Max. torque
Fuel systemFloat type carburetor
Cooling systemForced-air
Ignition systemElectronic
Lubricating systemFull pressure
Starting systemElectric starter
Fuel usedGasoline
Fuel tank capacity

Cylinder Block and Head

Cylinder block
Bore x Stroke94.0 mm X 77.8 mm (3.70 x 3.06 in)
Sleeve internal diameter94.010-94.110 mm (3.7012-3.7051 in)
Number of piston rings (compression / oil):2 / 1
Side clearanceTop0.051-0.076 mm (0.002-0.003 in)
Second0.051-0.076 mm (0.002-0.003 in)
Oil0.051-0.076 mm (0.002-0.003 in)
Ring end gapTop0.150-0.250 mm (0.0059-0.0098 in)
Second0.300-0.510 mm (0.0118-0.0201 in)
Oil0.510-0.630 mm (0.0201-0.0248 in)
Connecting rod small end ID15.890-15.920 mm (0.6256-0.6268 in)
Piston pin outer diameter15.850-15.890 mm (0.624-0.6256 in)
Cylinder Head
Valve Arrangement:OHV (overhead)
Valves:2
Valve steam diameterINTAKE5.920-5.970 mm (0.233-0.235 in)
EXHAUST5.920-5.970 mm (0.233-0.235 in)

Tightening torque specs

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
Breather3.0 Nm; 2.2 ft·lb
Carburetor to intake manifold8.0 Nm; 5.9 ft·lb
Carburetor solenoid5.0 Nm; 3.7 ft·lb
Connecting rod17.0 Nm; 12.6 ft·lb
Control bracket5.0 Nm; 3.7 ft·lb
Crankcase sump25.0 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 pump10.0 Nm; 7.4 ft·lb
Governor lever nut5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head10.0 Nm; 7.4 ft·lb
Muffler10.0 Nm; 7.4 ft·lb
Oil drain plug11.0 Nm; 8.1 ft·lb
Oil fill tube10.0 Nm; 7.4 ft·lb
Oil pump cover10.0 Nm; 7.4 ft·lb
Regulator / Rectifier5.0 Nm; 3.7 ft·lb
Rewind starter3.0 Nm; 2.2 ft·lb
Rocker ball set screw or nut5.0 Nm; 3.7 ft·lb
Rocker cover7.0 Nm; 5.2 ft·lb
Starter motor16.0 Nm; 11.9 ft·lb

Service Information

Engine
Max speed3,600 rpm
Valve clearance
Intake valve clearance0.08-0.13 mm (0.003-0.005 in)
Exhaust valve clearance0.13-0.18 mm (0.005-0.007 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)1.40 L (1.48 US. qt, 1.23 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.

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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.

4 Comments

  1. My engine is mounted on a DR mower/ snow thrower. I’ve had two engines lock-up. Repair facility said in both cases the push rods broke.

    • DR said the best they would do is replacement at half off even though second engine had less than an hour on it. Their locale distributer/repair wrote it was definitely a faulty engine! Wish I had my money back. When it worked it was GREAT, but it was down more than it worked.

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