Small Engines Chapter 9

During normal engine operation, the air-fuel mixture is typically a ratio of _____ part(s) of air to _____ part(s) of fuel.

15 to 1

What is the purpose of the carburetor float?

Maintain a constant level of fuel in the float bowl.

Vacuum carburetors _____.

are always mounted on top of the fuel tank

As soon as the intake valve opens or the intake port is uncovered in a gas engine, _____ forces air through the carburetor and manifold to fill that vacuum.

atmospheric pressure

The carburetor _____ is a round disc mounted on a shaft located at the intake end of the carburetor

choke

A(n) ______ carburetor can provide larger volumes of fuel for high-speed and high-power output.

downdraft

A wet bulb primer _____.

draws fuel from the fuel tank and pumps it into the air horn

An air-vane governor is operated by the stream of air created by cooling fins on the _____.

flywheel

A carburetor's primary function is to mix proper proportions of _____ and _____ to operate the engine.

fuel and air

A dry bulb primer _____.

increases the air pressure in the float bowl to force fuel into the main nozzle

As fuel is used from the float bowl, the float lowers and unseats a(n) _____ valve which lets fuel enter the bowl.

needle

When closed, the choke provides the _____ (leaner, richer) air-fuel mixture needed during the starting of a cold engine.

richer

Air velocity must be highest in the _____ carburetor.

updraft

In a two-cycle engine with a diaphragm-type carburetor, the fuel is drawn into the crankcase during the _____ of the piston.

upstroke

In order for the engine to operate, the carburetor must _____.

vaporize the gasoline

A(n) _____ in the float bowl is used to equalize the air pressure above the fuel in the float bowl and the air pressure entering the carburetor.

vent