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Model#: BGSN331977-0001-G1

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Briggs & Stratton 331977-0001-G1 540cc 21.0 HP Intek Series Vertical Engine with 1 in. Tapped 7/16 - 20 Keyway Crankshaft (CARB)

  • Briggs & Stratton 331977-0001-G1 540cc 21.0 HP Intek Series Vertical Engine with 1 in. Tapped 7/16 - 20 Keyway Crankshaft (CARB)
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(continental U.S.)
This item is no longer available.
It has been replaced by the BGSN33R877-0003-G1.


Briggs & Stratton's powerful Intek Series engines deliver unmatched reliability along with superior performance and durability. Featuring XRD technology, the Intek Series features enhanced durability and overall performance due to the consolidation of dozens of improvements.
  • Advanced debris management with dual-sealing cartridge style air filter provides the maximum protection to extend engine life
  • AVS anti-vibration system provides linear balancing to eliminate side motion to reduce vibration and smoothen operation
  • Dura-Bore cast iron cylinder sleeve withstands more wear and abuse while providing improved oil control
  • DuraLube splash lubrication system offers a gear driven system that continuously supplies oil to all internal parts
  • Heavy-duty Teflon coated bronze sleeve bearing withstands twice the belt load of standard bearings to reduce wear
  • High capacity panel air cleaner element increases cleaning capability for extended life
  • Model Specific Features: Pulse fuel pump, Choke-A-Matic choke, 12V Gear Drive start with 9 amp DC alternator, oil pump with filter and dipstick oil system
  • Please Note: Fuel tank omitted from this model
  • 540cc 21.0 HP Intek Series Vertical Engine w/ 1 in. Tapped 7/16-20 Keyway Crankshaft - 331977-0001-G1


Series: Intek
Length: 23.8 in.
Width: 21.2 in.
Height: 20.3 in.
Carburetor: Float-Feed
Controls: Remote
Cooling System: Air
Crankshaft Diameter: 1 in.
Crankshaft Length (Sump Face to Crankshaft End): 3-5/32 in.
Crankshaft Model Number: 591150
Crankshaft Tapping Size: 7/16-in - 20
Crankshaft Type: Keyway
Cylinder Bore: 3.70-in (94mm)
Cylinder Stroke Length: 3.06-in (77.6mm)
Engine Configuration: Vertical
Engine Displacement: 540cc
Engine Technology: OHV
Fuel Type: Gas
Governor: Mechanical
Governor Max. Speed: 3,300
Horsepower: 21
Lubrication System: Pressure Lube
Number of Cylinders: 1
Oil Capacity: 48 oz.
Power Type: Gas
Recommended Use: Lawn Mowers, Riding Mowers, Tow-Behind Mowers
Shipping Weight: 82 lbs.
Starter: Recoil


Product Reviews

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4 Questions | 5 Answers
Displaying questions 1-4
  • Q:

    what are the valve clearance on the intake and exhaust?
    Asked on 5/30/2015 by None from Roswell, New Mexico

    1 answer

    • Staff Reviewer


      The valve clearance on the intake is .003-.005-in and on the exhaust, its .005-.007-in.

      Answered on 6/1/2015 by Sonny from Lawrencville, GA
  • Q:

    I'm useing sae30 briggs oil and the engin is burning oil all the time. Mower is only three years old .
    Asked on 5/7/2015 by jim from new jersey

    2 answers

    • A:

      You most probably have a blown head gasket. This intek is noted for this issue.

      Answered on 6/29/2015 by vonMike from New Berlin WI
    • Staff Reviewer


      Please contact Briggs and Stratton directly at 800-444-7774 for assistance with your mower.

      Answered on 6/1/2015 by Taylor from Atlanta,GA
  • Q:

    What kind of oil does it take?
    Asked on 5/3/2015 by Bcox708 from Columbus ohio

    1 answer

    • Staff Reviewer


      It takes Briggs & Stratton lawnmower oil SAE 30 small engine oil.

      Answered on 5/4/2015 by Dennis from Atl
  • Q:

    Do you have a drawing of the bolt pattern for this engine?
    Asked on 10/1/2012 by Tom from Louisville KY

    1 answer

Displaying questions 1-4

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