What does the primer do on a lawnmower?

The primer on a lawnmower is a small bulb that helps to draw fuel into the carburetor, making it easier to start the engine. By pressing the primer, you inject a small amount of fuel into the engine, which provides the necessary mixture for ignition. This is especially useful for cold starts or when the mower has been sitting for a while. Essentially, it helps to ensure a quick and reliable start-up.