Where does a pressure injection carburetor obtain fuel pressure?

• A. From a gravity feed reservoir
• B. From an engine-driven fuel pump
• C. From a separate electric pump in the tank
• D. From atmospheric pressure in the intake

Answer: (B)

Pressure injection carburetors need a steady, controlled fuel pressure to meter and deliver fuel into the intake. That pressure comes from an engine-driven fuel pump, which maintains a constant supply regardless of engine speed or aircraft attitude. Gravity feed wouldn’t provide reliable pressure and could vary with climbs, turns, or fuel level. An extra electric pump in the tank isn’t the standard source for this system, and atmospheric pressure in the intake can’t create the necessary fuel pressure. So, the fuel pressure for a pressure injection carburetor is obtained from the engine-driven fuel pump.