Air Tech- Carburettor and Fuel Injection

What is the purpose of the Venturi in the carburettor?

• to cool down the fuel/air mixture for evaporation

• to heat up the fuel/air mixture for evaporation

• to draw out the fuel from the nozzle

• to accelerate air so the throttle butterfly doesn't flutter

What controls the rate at which air flows through the Venturi?

• the throttle butterfly

• the mixture control

• the accelerator pump

• the metering jet

Why does a carburettor have an atomisation and diffusion system?

• to improve vaporisation of the air

• to distribute the mixture to each cylinder

• to condense the mixture for smoother flow through the manifold

• to improve vaporisation of the fuel

What system ensures there's sufficient fuel for engine operation when the throttle control is closed?

• accelerating system

• enrichment system

• idling system

• idle cut-off system

Why is a mixture control required?

• To regulate the amount of fuel being metered

• To regulate the amount of air being metered

• To increase the rate of mixture flow

• To increase the rate of fuel flow as throttle is opened

In 'standard' sea level conditions, mixture should be set to...

• FULL RICH

• FULL LEAN

• IDLE CUT OFF

• 50% LEAN

How do you know when the mixture is leaned correctly on a fixed pitch propeller?

• the RPM increases to a maximum

• the RPM reduces to 2000rpm

• the manifold pressure increases to a maximum

• the manifold pressure reduces to 18 inches

What will an over-rich mixture most likely create?

• detonation due to too much fuel

• pre-ignition due to too much fuel

• detonation due to not enough fuel

• pre-ignition due to not enough fuel

Which is worse?

• pre-ignition

• detonation

Why should the engine be stopped using idle cut-off?

• to ensure no fuel is left in the tanks

• to ensure no fuel remains in the system

• because turning the magnetos to OFF could cause damage

• because the engine would detonated if the magnetos alone were used