MTC Preventive Maintenance Procedures 2

Question 1

How often should raw water impellers on marine engines typically be inspected or replaced?

Accepted Answer

Every 200–300 hours or annually, whichever comes first

Answer

Raw water impellers degrade with use and age, so OEM guidelines commonly specify inspection or replacement every 200–300 hours or once per season.

Question 2

What is the primary purpose of zincs (sacrificial anodes) in marine preventive maintenance?

Accepted Answer

To protect metal components from galvanic corrosion

Answer

Sacrificial anodes corrode preferentially to protect more valuable metal parts from galvanic corrosion in an electrolytic environment.

Question 3

When inspecting a marine diesel fuel system during PM, which condition in the fuel filter bowl is most concerning?

Accepted Answer

Dark fuel with visible water or microbial growth

Answer

Dark fuel with water or microbial (algae/bacteria) contamination can clog injectors and cause injection system damage if not addressed.

Question 4

A technician is performing PM on a marine outboard. What does checking the gear lube for a milky appearance indicate?

Accepted Answer

Water has infiltrated the lower unit, likely via a failed seal

Answer

Milky or grey gear lube indicates water intrusion through a damaged propeller shaft seal or drain/fill plug gasket.

Question 5

During a vessel's annual PM, what is the correct procedure when replacing a stuffing box packing?

Accepted Answer

Allow 1–2 drops per minute while underway to lubricate the shaft

Answer

A properly adjusted stuffing box should allow a slow drip (1–2 drops per minute) underway to provide lubrication and prevent overheating of the packing material.

(MTC) Marine Technician Certification Practice Test

(MTC) Marine Technician Certification Practice Test

MTC Preventive Maintenance Procedures 2