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

Every 5 years regardless of use

Answer

Only when overheating is observed

Answer

Every 1,000 hours

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

To improve fuel efficiency

Answer

To lubricate the propeller shaft

Answer

To reduce engine vibration

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

Slightly amber-colored fuel

Answer

Clear fuel with a faint diesel odor

Answer

Fuel with small air bubbles

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

The lubricant is new and unused

Answer

The gear ratio is incorrect

Answer

The lubricant has exceeded its viscosity rating

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

Pack tightly until no drips occur underway

Answer

Seal completely and pressure-test to 50 psi

Answer

Replace only if visible smoke is present

Question 6

What is the recommended action when PM inspection reveals hairline cracks in a fiberglass hull above the waterline?

Accepted Answer

Assess depth and structural involvement, then repair to prevent moisture intrusion

Answer

No action needed; gelcoat cracks are purely cosmetic

Answer

Monitor for six months before deciding on repair

Answer

Immediately haul the vessel and condemn the hull

Question 7

Which maintenance interval item is MOST critical for a marine gasoline inboard engine to prevent carbon monoxide accumulation in the bilge?

Accepted Answer

Inspecting and maintaining exhaust system integrity

Answer

Changing the oil filter

Answer

Lubricating the throttle cable

Answer

Checking the bilge pump float switch