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Genset Care

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Boat Maintenance Special:

By Capt. Bill Pike

Genset Care And Feeding

The humble generator is an invaluable shipmate, particularly for those of us who cruise in southern climes where air-conditioning is truly desirable. And the primary thing you can do to stretch your genset’s longevity is to run it, under load (after a proper warm-up), on a weekly basis.

Flush your generator’s raw-water cooling system, it’ll help keep her healthy.

Flush your generator’s raw-water cooling system, it’ll help keep her healthy.

“But I don’t have time,” you say. So hire a mechanic already—most likely there are professionals in your area who’ll routinely crank your main and auxiliary engines as part of a general mechanical-maintenance program.

A quick, illustrative story will show the wisdom of this. A couple of years ago, because I was routinely failing to give the Onan 4.0 Marine GenSet in Betty’s engine room a proper workout, I found myself forking over $1,241.47 to cover the reconditioning by a fuel injection equipment shop of three injectors, which had become obfuscated with shellacked fuel and other gunk.

One more genset-related pointer. Periodically flushing your genny’s raw-water cooling system with a descaler like Barnacle Buster from Trac Ecological ( is a known life-extender. Allowing any cooling system to become clogged with mineral and other deposits engenders overheating and stress, mechanical and otherwise. You can flush your system with a gizmo like the rather pricey Port-O-Flush Jr. ($380.95) from Trac or put something together yourself, using a 5-gallon bucket, an old bilge pump, and a few fittings and hoses. The mechanic I hire to do the job employs a device of the latter sort. He taps into my Onan via the hose emanating from its dedicated sea strainer, temporarily removes the impeller from the raw-water pump (and puts the covering plate back on), and completes his hookup by returning the Barnacle Buster fluid to the bucket from a spot just upstream of the marine muffler. Fire when ready, Gridley!