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New generators use less fuel, burn cleaner, and produce more power than their predecessors.

As the season winds to a close for some, it’s a good time to assess any needs or shortcomings your boat might have. The engines were serviced and they’re purring like proverbial kittens. New props were installed last spring and you managed not to ground them once. The electronics are current. Heck, even the canvas looks brand new. But what about the generator?

Like an insurance policy, or even a loyal deckhand (otherwise known as your spouse), many of us take the generator for granted. It always kicks on when we need it and provides much-needed juice for the myriad appliances many boats now carry. (Has it occurred to you how many appliances you’ve added since you bought the boat?) A microwave oven, a flatscreen, a DVD player, stereo amplifier, and other items gobble up electricity. 

Updating your boat’s generator can pay off in a number of ways. The latest and greatest models finally utilize electronic fuel injection to improve efficiency and reduce the output of carbon monoxide (CO). 

A control pad makes for simple operation.

Generator sizes are based on their output. The amount of kilowatts they produce is usually the number in the model name. Kohler (www.kohler.com) and Westerbeke (www.westerbeke.com) are among the manufacturers making low-CO generators, which reduce carbon monoxide emissions, making it safer and more comfortable to be aboard a boat while the generator is running. Westerbeke uses multiport electronic fuel injection on its low-CO models to improve fuel efficiency, while Kohler uses throttle-body injection. 

Westerbeke’s mighty mite is the 3.5 SBCG low-CO, a gasoline-powered 3.5-kW genset with multi-port EFI. It weighs in at a svelte 188 pounds and is compact at 27 inches long, 17 inches wide, and just under 15 inches tall. But in addition to providing more efficient fuel consumption, the unit has electronic control to maintain a constant engine speed, which keeps it from bogging down when under load. Westerbeke’s smallest diesel genset, by the way, is the 4.0 BCDA. With a footprint that’s not much larger than its gas-fired cousin (28 by 16 inches) and a height (20 inches) that’s just 5 inches taller, it is one of the true diesel space-savers on the market. At 356 pounds, it weighs significantly more than the gas genset.

Kohler has its own small-footprint diesel model gensets starting with the 490-pound, three-cylinder 6EKOD, which produces 6 kW and offers sophisticated functioning and touchscreen interface. It fits in a 31- by 21- by 22-inch envelope, which should save space in your engine compartment. The 9EKOZD is also powered by a three-cylinder diesel and produces 9 kW. It fits into a 34- by 21- by 22-inch space and weighs 548 pounds. Finally, the 11EKOZD is an 11-kW model based on a four-cylinder diesel engine, weighing in at 616 pounds. Each Kohler genset is available in 50- or 60-hertz models and comes with advanced controllers that provide trouble-free operation. The new touch-style control pad has power and start/stop buttons, a two-line, 12-character display, and a simpler setup process. There’s even a USB port for quick software installations and maintenance downloads. The controller has power management, a fuel primer, a hybrid voltage regulator, and an interface with SmartCraft instrumentation.

Cummins-Onan’s (www.powertoyachts.com) Quiet Diesel Series ranges from 4.5 to 99 kW in 50- and 60-hertz units. The Quiet Diesel Series generators are the first marine units with self-monitoring capability and network communication. All these models also meet EPA Tier II Emissions standards and have low vibration and noise output. 

Northern Lights (www.northern-lights.com) will have new marine generators with an integrated base frame at the Fort Lauderdale International Boat Show in October. Currently all models up to 38 kW are built with base frames, which integrates the enclosure into the unit, saving up to 27 percent of the overall size and reducing noise output. The company is also introducing a new exhaust-filtration system, improving sound absorption, and reducing the size of the housings to fit them into a smaller space.

If you’re wondering if you need a generator or you can still get by with an inverter, most experts say that if your electronic accessories require more than 3.5 kW, you need a generator. Add up the power requirements for each appliance you plan to run off the generator. Once you arrive at a total in kilowatt-hours, choose a generator rated to produce at least 20 percent more.

Trying to go cheap with a genset rated too close to your total will cost you in the end. Your new generator will wear out quickly and you’ll wind up buying the correct size replacement unit sooner than should be necessary. Don’t go off the deep end in the other direction either. Using an oversize genset runs the unit at an insufficient load, which will cause it to operate inefficiently, which increases fuel consumption. A generator should run at least at 25-percent load with the ideal being 35 to 70 percent. 

Finally, if you like to take longer cruises, I recommend installing a remote canister-style fuel-water separator in-line for your generator. Most gensets come with a small integral fuel-water separator, but the remote version can save you some headaches by preventing contaminants from getting to that smaller filter because it will clog quickly. Position the remote separator ahead of the motor in the hose routing and make it accessible so you can change the element or clean it out if it gets clogged.

This article originally appeared in the September 2012 issue of Power & Motoryacht magazine.