Definition
In a float-type carburetor, the discharge nozzle is the small outlet, located in the venturi, through which fuel is drawn from the float chamber and sprayed into the airstream entering the engine. The pressure drop created by air accelerating through the venturi pulls fuel up through the nozzle, where it atomizes and mixes with the incoming air to form the combustible fuel-air charge.
Plain English
It is the tiny spout inside the carburetor where fuel comes out and gets mixed into the air being sucked into the engine.
Context Anchor
Seen in carburetor diagrams and explanations of how fuel leaves the float chamber and enters the airflow.
Derivation
‘Discharge’ comes from the Old French ‘descharger’, meaning to unload or release. ‘Nozzle’ is a small ‘nose’ — a projecting spout. Together: the small spout that releases the fuel.
Why Pilots Care
A blocked or malfunctioning discharge nozzle disrupts the fuel-air mixture, which can cause rough running, power loss, or engine stoppage.
Intuition Check
Discharge here does not mean an electrical spark or a battery going dead. It means fuel being released from a small outlet into the carburetor airflow.
Example Sentence 1
As airflow through the venturi increased, fuel was drawn from the float chamber and sprayed into the air through the discharge nozzle.
Example Sentence 2
During the preflight inspection the pilot checked the carburetor for any debris that might block the discharge nozzle.