Here's why:
* Two valves per cylinder: Most modern gasoline engines, including those in lawn mowers, use two valves per cylinder: one intake valve and one exhaust valve.
* Two cylinders: Since your engine has two cylinders, it will have a total of 4 valves (2 valves/cylinder * 2 cylinders = 4 valves).
However, there are some exceptions:
* Older engines: Some very old Briggs & Stratton engines might have only one valve per cylinder (an "overhead valve" design), resulting in just 2 valves total.
* Specific models: There may be specific Briggs & Stratton models with variations. If you need to confirm the valve count for your exact model, you can refer to the engine's manual or check the engine's identification tag.
