Years ago I chartered a Tolleycraft for a cruise around Washington State’s
San Juan Islands. Although the boat had seen considerable use, she was
a sturdy old girl and eminently reliable, with one notable exception:
her genset. Located in the lazarette, right under an indifferently sealed
hatch, it was constantly showered by sea water. Consequently, the thing
looked like it had just been dredged out of some sunken World War II U-boat.
And ran like it, too.
The charter operator claimed to be scrupulous about genset maintenance,
which to him consisted solely of annual oil changes and fixing the set
when it didn’t run. As a result, just about everything on my charter
boat’s unit was leaking, rusting, loose, held together with duct
tape, or some combination thereof, and not surprising, it started infrequently
and ran with the assurance of a cardiac patient in a marathon.
Gensets have thankfully become a good deal more reliable and durable since
then, but they still need care if you want them to start promptly and
run without interruption. You know the major things you need to do to
make this happen, like changing the oil and zincs, but there are other
small maintenance tasks that are often overlooked, which also ensure that
your genset will be trouble-free. To find out what those are, we asked
the people who should know: genset manufacturers.
Years or Hours? Changing the oil and filter according to the manufacturer’s
recommendations seems like a no-brainer, but are you sure you know what
those recommendations are? Most intervals are expressed as a combination
of calendar time and engine time—say, one year or 100 hours, whichever
comes first. According to Greg Pressman, Onan’s service manager,
when it comes to oil changes, boaters often concentrate on the time and
ignore the hours. “Usually they change the genset oil when they change
the engine oil,” he says. “They forget that gensets often get
a lot more use than mains.” Make sure you heed those words “whichever
comes first” for all service recommendations.
Cool(ant) Change. Even boaters who maintain proper oil-change intervals
often forget that coolant also should be changed periodically. According
to Kohler, you should change yours every 400 hours or six months. That’s
because coolant degrades over time, even when the genset isn’t being
used. When this happens, it can no longer perform its many duties, which
include elevating the boiling point of plain water, lubricating the circulating
water pump, preventing oxidation, and minimizing mineral deposits that
naturally occur in water. All the manufacturers we spoke to also say that
whenever possible, you should flush the system with fresh water after
draining but before adding new coolant.
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