MST MST Marine Fuel Systems 3

Question 1

What is the proper way to dispose of water-contaminated fuel removed from a marine tank?

Accepted Answer

Take it to a certified hazardous waste facility or marina fuel recycler

Answer

Contaminated fuel is hazardous waste and must be disposed of at an approved facility — dumping it overboard or on land is a federal violation.

Question 2

A fuel-injected outboard has low fuel pressure at the rail. After replacing the fuel filter, pressure is still low. What is the next component to inspect?

Accepted Answer

The electric fuel pump

Answer

If a new filter does not resolve low rail pressure, the electric fuel pump is likely weak or failing and should be tested for volume and pressure output.

Question 3

Which federal regulation requires marine fuel tanks to be certified for use in boats?

Accepted Answer

33 CFR Part 183 (Fuel Systems)

Answer

33 CFR Part 183 establishes Coast Guard standards for fuel systems on recreational boats, including tank certification requirements.

Question 4

What symptom would a cracked VST (vapor separator tank) O-ring on a four-stroke EFI outboard most likely cause?

Accepted Answer

Fuel leak at the VST and possible lean run condition

Answer

A cracked VST O-ring allows air to enter the high-pressure fuel circuit and fuel to leak externally, causing lean operation and a visible fuel leak.

Question 5

Ethanol in marine fuel is known to degrade what common fuel system component?

Accepted Answer

Rubber fuel lines and carburetor diaphragms

Answer

Ethanol swells and deteriorates older rubber fuel lines, gaskets, and carburetor diaphragms not designed for alcohol-blended fuels.

(MST) Marine Service Technician Practice Test

(MST) Marine Service Technician Practice Test

MST MST Marine Fuel Systems 3