priming pump[′prīm·iŋ ‚pəmp]
A device on motor vehicles and tanks, providing a means of injecting a spray of fuel into the engine to facilitate starting.
A small, hand- or electrically operated pump, used to spray gasoline into the induction system of a reciprocating engine for starting the engine. The fuel does not pass through the carburetor. The pump must be locked during flight to avoid excessive fuel being drawn into the cylinders, especially at low power settings, which may result in an overly rich mixture and the realization of much less range than anticipated.