Is the Generator Ready?

Generators need tender loving care to be a reliable source of power.

Marine generators don’t have it easy. They labor away in tight, stifling corners of the engine room or lazarette and, all too often, are overlooked until something goes wrong. If it’s been a while since your generator was pressed into service, chances are it could use a bit of care. This is especially true if you are planning a summer cruise, which likely starts very soon. The time to ferret out potential problems isn’t at anchor in a secluded cove.


Preventive Maintenance

Before the trip, review your generator’s operating manual and perform all necessary services: oil and filter changes, zinc replacements, belt inspection and replacement, air filter cleaning or replacement, and leak checks. It’s important to begin the process well ahead of the departure date, because if you detect a problem, you will have time to schedule service or repairs. Service centers can be busy at the peak of boating season.

I also suggest the following inspection and troubleshooting routines:

  • Ventilate the compartment, remove any debris such as oily rags or stray parts from the area, and clean the generator’s exterior surfaces and the surrounding area.
  • Make sure the starting battery is fully charged and the terminals are clean.
  • Check and tighten all hose clamps and fittings, especially the exhaust connections.
  • Inspect all electrical connections, and tighten and clean them as needed.
  • Inspect all mounting hardware and other mechanical nut-and-bolt connections to ensure they are secure.
  • Check all fluid levels and add or replace as necessary.
  • Verify all through-hulls are operational.
  • Make sure the generator can be started from all onboard control stations.
  • Turn-on all electrical loads that would be used during generator operations, being sure not to overload the generator. Also, make sure the generator will handle the load it is rated for. As the ammeter climbs, make sure the frequency doesn’t drop much below 60 Hz. Listen for the generator bogging down and watch for black smoke in the exhaust.

A generator that can’t carry its rated amps is just as unhealthy as a main engine that won’t turn at full rpm, and whatever problem is causing the lost power will likely get worse. Run the generator under at least 80 percent load for 30 minutes and watch the temperature gauge to make sure the cooling system is up to the task.

Note the generator’s current operational hours and add the number of hours you expect to log during the trip. Based on the total hours and the service intervals outlined in the operation manual, determine if any service will be required during the trip. If service is required, identify the necessary replacement parts and fluids, and purchase them ahead of time.


Daily Care

Once your cruise is underway, there are a few simple routines that should be performed each day to ensure the generator remains in peak operating condition:

  • Inspect the generator for leaks.
  • Perform any required maintenance based on the operation manual and total hours.
  • Check belt tension, oil and coolant level, and the seawater strainer.



In addition to items required for routine maintenance, it’s a good idea to carry additional items needed to perform common repairs. Having the parts readily at hand could prove invaluable if in an area where parts are difficult or impossible to obtain.

I suggest the following spare parts for cruising boaters:

  • Primary and secondary fuel filter elements
  • Oil filters
  • Air filter
  • V-belt
  • Thermostat and gasket
  • Seawater pump
  • Spare seawater pump impeller and gasket
  • Full set of injectors and washers
  • Fuel pump
  • Solenoid