Briggs & Stratton Lawn & Garden Equipment Engine Hex Screw 691108 0.48 x 4.00 x 4.00 Genuine OEM. This is a Genuine OEM Briggs & Stratton part. This screw (part number 691108) is for lawn and garden equipment engines. Follow appropriate safety practices when installing screw 691108.- Briggs & Stratton Lawn & Garden Equipment Engine Hex Screw 691108 0.48 x 4.00 x 4.00 Genuine OEM.