Engine Room Inspections
ritical checks for your annual haulout


by Frank Lanier


While most boaters are onboard with the basics of engine room maintenance (checking the engine oil, draining fuel filters, etc) your annual haul-out is an excellent time to inspect those attention starved items that may not be part of your normal maintenance routine.

Prepping for your annual haul-out ideally starts with the vessel still in the water.  Conduct a through sea trail now for issues to be addressed while hauled (worn engine mounts, leaky stuffing boxes, etc).  Although the following inspection list is not all inclusive, combining it with the items noted during your sea trial should go a long way towards preventing unexpected downtime during the coming year.

General engine and generator checks

  • Change oil and filters as per manufacturer’s recommendations (annually at a minimum).  Date filters with a permanent marker as a visual scheduling reminder.
  • Check all belts for proper tension.  Using your thumb, apply moderate pressure halfway between pulleys – the belt should deflect around 3/8” depending on its length.  Replace cracked, fraying, or delaminated belts and always keep a spare onboard for each.
  • Check engine beds and mounts for cracks, broken bolts, or looseness.  Worn, failing, or undersized engine mounts can cause a multitude of problems, such as shaft misalignment, which can lead to vibration, shaft damage, and failure of other components (cutless bearings, stuffing boxes, transmissions, or even the hull itself).  While inspecting the rear engine mounts, give the propeller shaft a strong tug horizontally and vertically to detect any looseness or wear in the transmission.
  • Provide chafe protection for all engine and generator hoses and wiring where necessary.

Cooling and exhaust systems

  • Check coolant level and concentration – drain, flush and change coolant as per manufacturer’s instructions.  Some coolants may last up to 5 years, however their rust inhibiting qualities may not make it that long.
  • Check engine zincs, with an eye towards replacement if in doubt they’ll last the season.
  • Check coolant and raw water pumps for leaks – pull and inspect impellor blades for set or deterioration.  Replacing impellors annually is cheep insurance considering the headaches a failed one can cause (keep the undamaged used ones onboard as emergency spares).
  • Pull, clean, and inspect all sea strainers – note seal kit numbers to purchase onboard spares.
  • Check cooling water seacocks for corrosion, leaks, missing hardware, physical damage, and smoothness of operation.  If frozen or damaged, remove for maintenance or replacement as required.  To check the seacock, remove its hose and look through the seacock to verify operation and spot blockages (this also gives you a chance to inspect the hose).  Another option is shining a flashlight into the through-hull from the outside and observing its operation while someone inside opens and closes it.
  • Inspect cooling system hoses for damage, deformation (such as swelling at the ends) or crackling sounds when squeezed – hoses should be firm, but supple.  Make sure each is double clamped with stainless steel clamps where possible.   Double hose clamps should only be installed where there is sufficient length of barb available (at least 1/4″ from the end of the hose barb or fitting to the 2nd  clamp).
  • Thoroughly inspect all engine and generator exhaust system components for leaks, damage, corrosion, etc.  This is extremely important, as leaks here can introduce CO into the interior of the vessel with deadly results.

Fuel System

  • Inspect the entire fuel system (from fill to vent) for damage, leaks, corroded clamps, etc.
  • Inspect all hoses for chafing, deterioration, etc, ensuring all are USCG approved types.
  • Check that all hoses are double clamped (where possible) and that installations provide sufficient slack to prevent damage from engine vibration.
  • Verify the system is properly grounded (fill to tank, tank to vessel grounding system).  Check all connections to ensure they are in good order.
  • Check each fuel tank for corrosion, leaks, and proper mounting.
  • Verify operation of fuel manifold valves, tank shut off valves, and all emergency fuel shut offs (such as those typically located at the helm).


  • Inspect engine room exhaust systems for proper operation (this is particularly important for gasoline powered vessels).
  • Ensure all exhaust blowers are operational.
    Inspect all ventilation ductwork – replace if split or damaged.
  • Ensure exhaust ductwork ends are secured as nearly as practicable below the engines and above the normal accumulation of bilge water.

Fire Extinguishers

  • Check all fixed and portable units, verifying each have been inspected and tagged within the past year by a licensed service facility.  The typically dry chemical hand held units most boaters buy should be considered disposable and replaced every 5 years or so.
  • Verify operation of all gasoline vapor detectors.
  • Ensure the engine compartment is clean and free of oily rags, cleaning supplies, or other flammable materials.


  • Batteries should be installed in liquid tight / acid-proof containers and secured against movement (no more than 1 inch in any direction).
  • Verify all terminals are corrosion free, tight, and properly covered (to prevent accidental shorting).
  • Top off wet cell batteries with distilled water.
    Loose or corroded battery cables are common problems, however another is equipment hot-wired directly to the battery without using a fuse or breaker – a poor installation practice and potential fire hazard.
  • Consider changing all battery connections using wing nuts to standard connectors. Wing nuts are difficult to properly torque and may work loose due to vessel movement.


  • Verify that engine room AC outlets are the GFCI (ground-fault interrupt) type.  You’ll also need to verify GFCI operation (simple plug-in testers can be purchased at most any hardware store for under $10).
  • If the existing receptacle boxes are not deep enough to accept a GFCI type outlet and can’t be easily changed, another option is installation of a new box of adequate size with GFCI near the main panel.  Existing circuits can then be downstream fed from the new box, providing them with GFCI protection.
  • Keep an eye out for loose, hanging wire runs, damaged conductors and chafe, especially where wires pass through a bulkhead (these should be protected by rubber grommets).
  • Replace all electrical tape joints and those utilizing household twist on “wirenuts” with proper marine grade connectors – both eventually fall off, leaving exposed conductors).

Bilge pumps

  • Verify operation of all engine room bilge pumps.
  • Ensure pumps and automatic switches are securely mounted.
  • If equipped with an automatic switch, ensure pumps can also be turned on via a separate manual switch (in the event of a float switch failure).
  • Pull, clean, and inspect all strum boxes (intake filters) ensuring each is properly mounted.