Genuine Briggs & Stratton 495606 Carburetor Rebuild Kit. If the engine is running poorly then the carburetor may be restricted and need to be cleaned and some of the internal seals and diaphragm replaced.
Fuel Tank Cap, 3-5 HP Horizontal, Selected Model
Small engine carburetor assembly. If the engine runs rough, then the carburetor may be restricted and unable to supply enough fuel and air mixture to the engine.