Engine

Boat engine maintenance checklist before the season

Updated: 5 min readCaranva Boats

Quick answer

Before the season, check: engine oil and filter, gearbox or drive oil, fuel filters and water separator, raw-water pump impeller, anodes, belts and hoses, coolant, batteries and connections, then run a sea trial checking temperature, oil pressure and water flow from the exhaust.

Engine checklist

Lubrication

  • Oil and filter change (every 100–200 h or yearly).
  • Gearbox, transmission or drive oil.

Fuel

  • Fuel filter and water-separating pre-filter.
  • Hoses, clamps and tank vent.
  • Drain water from the separator.

Cooling

  • Raw-water pump impeller (every 1–2 years).
  • Clean raw-water strainer and working seacock.
  • Coolant level and condition.
  • Heat-exchanger anodes.

Electrical

  • Batteries charged, terminals clean and tight.
  • Alternator and belt.
  • Starter motor and wiring free of corrosion.

Sea trial

  • Starts easily.
  • Water flowing from the exhaust.
  • Normal temperature and oil pressure.
  • No vibration, unusual smoke or leaks.

Outboard specifics

  • Freshwater flush after every use.
  • Lower-unit oil and greasing points.
  • Check propeller, shear pin and leg anode.

If you’d rather not

A marine mechanic or an outboard specialist can do the full service. See our engine service page and plan the year with the maintenance calendar.

Frequently asked questions

How much does an annual boat engine service cost?

It depends on engine type and size and on the parts needed. Ask for quotes with parts and labour itemised so you can compare.

What happens if I don’t replace the impeller?

It hardens and breaks over time; without water flow the engine overheats within minutes and can damage the exhaust and head gasket.

Related guides

See all guides