Oil Capacity. The oil capacity of the Briggs & Stratton 4.50 foot-pounds gross torque engine is 20 ounces. Adding too much oil, according Briggs and Stratton, can cause engine damage.il Capacity. The oil capacity of the Briggs & Stratton 4.50 foot-pounds gross torque engine is 20 ounces. Adding too much oil, according Briggs and Stratton, can cause engine damage.