FAA Aviation Mechanic Powerplant (AMP)Fuel, Induction and LubricationMedium
A mechanic is explaining the purpose of the economizer (power enrichment) system in a float-type carburetor to an apprentice. What is the primary function of this system?
- ATo supply fuel to the engine only during idle operation
- BTo provide additional fuel enrichment at high power settings to aid engine cooling and prevent detonation
- CTo prevent fuel vapor lock during hot-weather ground operation
- DTo lean the mixture automatically as altitude increases
Show answer & explanationAnswer & explanation
Correct answer: B. To provide additional fuel enrichment at high power settings to aid engine cooling and prevent detonation
The economizer, or power enrichment system, adds extra fuel at high power/full throttle settings beyond what the main metering system provides. This enriched mixture aids in cooling the cylinders and combustion chamber, helping to prevent detonation at high power.
Why the other options are wrong
- A. Idle fuel is supplied by the idle system, not the economizer.
- C. Vapor lock prevention involves fuel line design and boost pumps, not the economizer valve.
- D. Automatic mixture leaning with altitude is a separate function of altitude compensation, not the economizer.
Economizer (Power Enrichment) System
A carburetor system that enriches the fuel/air mixture at high power settings to aid cylinder cooling and prevent detonation.
- Activates near full throttle/high manifold pressure
- Adds fuel beyond main metering system output
- Helps prevent detonation and excessive cylinder head temperatures
Memory trick: Economizer = extra fuel firefighter cooling hot cylinders at full power