Which three components form the induction system in a normally-aspirated engine?

• A. An air intake (scoop) and duct to direct ambient air to the carburetor; The carburetor; The inlet manifold between carburetor/throttle unit.
• B. The air intake; The carburetor; The exhaust manifold.
• C. The air intake; The throttle valve; The inlet manifold.
• D. The air intake and duct; The carburetor; The inlet manifold between carburetor/throttle unit.

Answer: (A)

The induction system in a normally-aspirated engine is the path that brings air in, meters it, and distributes the air-fuel mixture to the cylinders. The three components that make up this path are: the air intake with its ducting that channels ambient air to the engine, the carburetor where the air is metered and fuel is mixed, and the inlet (intake) manifold that delivers the air-fuel mixture from the carburetor to each cylinder.

Why this set fits best: the throttle valve is typically integrated inside the carburetor, so it isn’t regarded as a separate induction component. The exhaust manifold belongs to the exhaust system and isn’t part of induction. Therefore, the combination of the air intake and duct, the carburetor, and the inlet manifold best represents the induction system for a normally-aspirated engine.