Briggs & Stratton Bolts & Screws
Engine bolts and screws secure carburetor assemblies, blower housings, valve covers, and mounting plates on Briggs & Stratton small engines. Lawn mower engine bolts predominantly use SAE/UNC thread standards including common sizes 1/4-20, 5/16-18, and 3/8-16 with corresponding socket sizes. Small engine screws feature various head types including hex, Torx, Phillips, and slotted designs for specific applications. Engine mounting bolts typically require 3/8-inch diameter with thread length determined by equipment manufacturer specifications. Briggs & Stratton bolts include standard hex bolts, shoulder bolts for mufflers and fuel tanks, and thread-forming screws for vertical shaft blind holes. We hold Briggs & Stratton engine screws in stock and sell worldwide.
Available Briggs & Stratton Bolts & Screws
Bolt
703798
Briggs & Stratton
£2.25
In Stock
Wheel Bolt
2108765SM
Briggs & Stratton
£4.05
In Stock
Bolt, 5/16-24 X 2 Tapered, Axle R/H
7011013YP
Briggs & Stratton
£5.03
Available
Screw
793458
Briggs & Stratton
£4.00
In Stock
Screw
691664
Briggs & Stratton
£4.15
In Stock
Screw
690664
Briggs & Stratton
£4.35
In Stock
Screw
691683
Briggs & Stratton
£4.15
In Stock
Screw
691688
Briggs & Stratton
£3.80
In Stock
Screw
691061
Briggs & Stratton
£3.60
In Stock
Screw
691636
Briggs & Stratton
£3.70
In Stock
Screw
592244
Briggs & Stratton
£4.50
In Stock
Screw
690297
Briggs & Stratton
£3.90
In Stock
Frequently Asked Questions
What are shoulder bolts and where are they used?
Shoulder bolts feature smooth unthreaded shanks between the head and threads, acting as precise alignment pins. Used primarily on muffler mounts (allowing thermal expansion through slotted holes) and fuel tank attachments (preventing over-tightening damage). Common sizes are 5/16-18 and 3/8-16 with various shoulder diameters. Part numbers like 691340 and 597133 are common replacements. Standard bolts with washers/sleeves can substitute temporarily, but OEM shoulder bolts ensure proper fit and prevent component shifting.
How do you identify and replace missing engine bolts?
Use your engine model number to access Briggs parts diagrams online showing exact part numbers and specifications. Measure existing identical bolts for diameter, thread pitch, and length—hardware store thread gauges confirm uncertain sizes. Note head style (hex, Torx, Phillips) and type (standard, shoulder, flange). Common sizes: shroud bolts 1/4-20, carburetor 1/4-20 or 5/16-18, head bolts 5/16-18, mounting 3/8-16. OEM bolts ensure proper Grade 5 strength. Generic hardware acceptable for non-critical applications.
What are thread-forming screws and when should they be used?
Thread-forming screws (tri-lobe or tri-flow design) cut their own threads during installation into unthreaded aluminum blind holes. Used extensively on vertical shaft engine mounting. Feature triangular cross-section that self-aligns and resists stripping. Briggs recommends these over standard bolts after testing. Install perpendicular with steady pressure, never back out and reinstall repeatedly as threads wear. Torque lower than standard bolts. Available through Briggs dealers, not typically at generic hardware stores.
What thread types does Briggs & Stratton use - metric or SAE?
Briggs & Stratton engines predominantly use SAE (UNC - Unified National Coarse) threads rather than metric. Common sizes include 1/4-20 for carburetor and shroud bolts, 5/16-18 for head bolts and general assembly, and 3/8-16 for mounting bolts. Socket sizes follow SAE standards: 1/4" bolt uses 7/16" socket, 5/16" uses 1/2", 3/8" uses 9/16". When replacing lost bolts, verify thread type with thread gauge or by testing existing fasteners before purchasing replacements.
Why do carburetor mounting bolts keep coming loose?
Carburetor bolts loosen from insufficient torque, using wrong screwdriver types (flathead on Torx), stripped threads, or compressed gaskets reducing clamping pressure. Solutions: use proper Torx or Phillips bit, apply blue Loctite threadlocker, replace worn gaskets, verify threads aren't stripped (bolt should tighten firmly, not spin freely). Thread size typically 1/4-20 requiring 65 inch-pounds torque. Some mechanics install longer bolts with nylock nuts on the backside for permanent security. Regular inspection prevents air leaks and stalling.