Preventive Maintenance Procedures Flashcards

A preventive maintenance log shows a marine vessel's trim tabs have not been serviced in three years. Which component should the technician prioritize inspecting first?

Answer: The hydraulic actuator hoses and ram seals for leaks or deterioration

Hydraulic hoses and ram seals are most vulnerable to age-related cracking and leakage, which would cause trim tab failure or hydraulic fluid contamination of the bilge.

When applying antifouling paint as part of an annual PM haul-out, what is the correct preparatory step before applying new paint over old ablative antifouling?

Answer: Wash the hull, lightly sand to scuff the surface, and ensure old paint is firmly adhered

A clean, scuffed surface promotes adhesion of the new antifouling coat; loose or peeling old paint must be removed to prevent the new coat from delaminating.

During PM on a twin-engine vessel, a technician finds one engine's raw water strainer basket cracked. What is the correct PM action?

Answer: Replace the basket immediately; a cracked strainer can collapse and block raw water flow

A cracked raw water strainer basket can collapse, completely blocking cooling water flow to that engine and causing rapid overheating.

What is the correct PM procedure for a marine vessel's rubber exhaust hose connections (wet exhaust)?

Answer: Inspect for softness, cracks, heat damage, and ensure all hose clamps are double-clamped and tight

Wet exhaust hoses degrade from heat and seawater cycling; double clamps and intact hose material prevent exhaust gases and water from entering the bilge.

A marine technician is setting up a PM schedule for a diesel inboard. When should the injector nozzle spray pattern be tested?

Answer: At OEM-recommended intervals (typically 1,000–2,000 hours) or when smoke, rough running, or hard starting is observed

Injector testing at OEM-specified intervals (or when symptoms arise) ensures proper atomization, combustion efficiency, and prevents engine damage from poor spray patterns.

During a winter layup PM procedure, what is the purpose of fogging oil sprayed into a gasoline marine engine's intake and spark plug holes?

Answer: To coat internal cylinder surfaces and prevent rust during storage

Fogging oil leaves a protective oil film on cylinder walls, rings, and valves to prevent oxidation corrosion during months of non-use.

What is the primary reason a marine technician should use a torque wrench when reinstalling the propeller nut during PM?

Answer: To achieve the OEM-specified clamping load without over- or under-tightening, protecting the shaft taper and hub

Under-torquing allows the prop to spin on the shaft taper; over-torquing can damage the shaft or make future removal extremely difficult, so OEM torque specs must be followed.