It supplies electricity to the spark plugs and is completely independent of the aircraft electrical system. The oil filter is the white horizontal cylinder. The gyro suction pump is the horizontal metal cylinder with the red stripes. The engine mount is in the upper right. Most aircraft with carburetors have them mounted on the bottom of the engine.
Air normally flows into the engine through the tube on the right after it is filtered.
It then passes into the mixing box on the bottom of the carburetor. When the pilot selects carburetor heat, a valve in the mixing box turns diverting heated air into the carburetor from the tube on the left. The throttle connection is visible on the top of the carburetor.