EETC Carburetor Service and Repair 2

Question 1

What tool is required to adjust the mixture screw on many EPA-compliant carburetors equipped with limiter caps?

Accepted Answer

Splined or D-shaped limited adjustment tool

Answer

Standard flat-blade screwdriver

Answer

Phillips #2 screwdriver

Answer

Torque wrench with a socket adapter

Question 2

What symptom most clearly indicates the idle mixture screw is set too lean?

Accepted Answer

Engine runs rough and tends to stall at idle speed

Answer

Black smoke emitting from the exhaust at idle

Answer

Excessive fuel consumption during normal operation

Answer

Fouled, black-coated spark plug electrode

Question 3

What is the correct initial starting position for a typical carburetor mixture screw before fine-tuning?

Accepted Answer

1 to 1.5 turns out from lightly seated

Answer

Fully closed (seated) with zero turns out

Answer

3 turns out from lightly seated

Answer

Fully open to maximum travel

Question 4

Which carburetor adjustment directly sets the engine idle speed?

Accepted Answer

Turning the throttle stop screw in or out

Answer

Rotating the main jet to a larger orifice

Answer

Raising or lowering the float height

Answer

Replacing the venturi insert with a different size

Question 5

What is the correct method for verifying carburetor adjustment after making changes?

Accepted Answer

Test performance at idle, mid-range, and full throttle under actual load

Answer

Rev the engine to full throttle briefly with no load attached

Answer

Run the engine at idle for 30 seconds and listen for smoothness

Answer

Check the color of fuel remaining in the bowl after shutdown

Question 6

What color exhaust smoke on a four-stroke engine indicates a rich fuel mixture condition?

Accepted Answer

Black smoke indicating unburned fuel

Answer

White smoke indicating water vapor or coolant

Answer

Blue smoke indicating oil burning

Answer

Gray smoke indicating normal combustion

Question 7

What does float height measurement determine in a carburetor?

Accepted Answer

The fuel level maintained in the float bowl

Answer

The throttle plate angle at idle position

Answer

The diameter of the main jet orifice

Answer

The size of the air bleed passage