Source : Webster's Revised Unabridged Dictionary (1913)

Self-starter \Self`-start"er\, n.
   A mechanism (usually one operated by electricity, compressed
   air, a spring, or an explosive gas), attached to an
   internal-combustion engine, as on an automobile, and used as
   a means of starting the engine without cranking it by hand.

Source : WordNet®

self-starter
     n 1: an energetic person with unusual initiative
     2: an electric starting motor that automatically starts an
        internal-combustion engine