Abstract: A starting system for an internal combustion engine is provided for enhancing engine startability and performance by simultaneously controlling the volume of air flowing through a carburetor and the ratio of an air/fuel mixture through a single manual operation. The starting system is constructed to utilize atmospheric air control feed back to a carburetor and includes a piston disposed with a chamber which accesses two atmospheric ports. When the piston is positioned to fully close a first of the ports, a second of the ports is fully open. Similarly, when the piston fully opens the second port, the first port is fully closed. The two atmospheric ports access the carburetor idle system and intake manifold of the engine respectively. For starting of the engine in cold temperatures, the starting system also includes a fuel prime arrangement for enriching the ratio of air/fuel delivered to the engine.