from The Century Dictionary.
- noun The lever attached to and operating a starting-gear; specifically, in vertical-beam engines with lifting poppet-valves, such as side-wheel marine engines, the lever which operates a supplementary rock-shaft by which the valve-rods are lifted in starting slowly from rest: used also for working the engine backward when it is not designed to operate in either direction by its own valve-gear.
Sorry, no etymologies found.
With a final wave of his hand, Wertheimer grasped the starting-lever.
He pulled the starting-lever forward, stopping his headway; for he must be sure of his welcome.
He threw back the starting-lever, and the thing began moving.
This is the road to Bryan, isn't it? "she asked, with her hand on the starting-lever.