Small engine primer bulb. The primer bulb draws additional fuel into the carburetor to help start the engine.
NGK Spark Plug (BPM8Y). The spark plug ignites the fuel and air mixture in the engine's cylinder to power the engine. If the spark plug is has fouled (if the tip of the spark plug is burnt or damaged), the engine may not start or may run rough.
Fuel tank vent (also called a check valve). The fuel tank vent allows air to re-enter the fuel tank. If the vent is clogged, the engine may stall.
Walbro carburetor repair kit. If the carburetor is clogged, the engine won't get enough fuel. As a result, the engine may not start or may run rough. It is often possible to repair the carburetor if it is clogged.