PPL Air Tech - Carburettor

What is the fuel air ratio average by weight?

• 1:8

• 1:10

• 1:12

• 1:14

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 doesnt 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 vapourisation of the air

• to distribute the mixture to each cylinder

• to condense the mixture for smoother flow through the manifold

• to improve vapourisation 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

When should the mixture be leaned?

• on a climb

• on start up

• on descent

• on alternator failure

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