Definition
A small hand-operated pump that draws fuel from the tank and delivers it directly into the intake ports of the engine cylinders or into the intake manifold, used to aid starting — particularly in cold weather when the engine is hard to start.
Plain English
A little pump in the cockpit that squirts a small amount of fuel straight into the engine to help it start, especially when it is cold.
Context Anchor
You encounter the fuel primer during engine starting procedures, especially in cold weather or after the aircraft has been sitting.
Derivation
From the verb 'to prime,' meaning to prepare something for action by supplying it with what it needs to begin working — the same sense as priming a water pump. The primer 'primes' the engine with fuel before the start.
Why Pilots Care
Reduces cranking time, protects the starter and battery, and prevents damage from prolonged attempts to start an engine without sufficient fuel vapor.
Analogy
It is like giving a campfire a small, careful starter amount before the main fire catches. Too little may not help, and too much can create trouble.
Intuition Check
A fuel primer is not a teaching book or a paint coating. Here, primer means a device or action that prepares the engine to start by adding a small amount of fuel.
Example Sentence 1
Before starting the engine on a cold morning, the pilot gave the fuel primer two strokes and then locked it.
Example Sentence 2
After a flooded start, the checklist called for clearing the engine with the throttle open and no further use of the fuel primer.