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How to Top Off a Boat's Fuel Tank
Without Spilling Gas Overboard

a fuel collar prevents spilling gas when filling a boat fuel tank

In the old days we simply shrugged our shoulders if a few ounces of premix dripped overboard and made an ever widening rainbow slick on the water. But today carelessness at the fuel dock can cost you a USCG citation and big fine.

Careless Refueling Habits
Can Cost You
A USCG Citation And A Fine

Even worse, we now know that a sheen of fuel evaporates into the atmosphere polluting the air we and our children breathe. Because of legal and environmental liability some timid boaters make sure the fuel dock handles the operation. But for those of us who prefer hands-on boating here follow a couple of steps for clean as a whistle refueling.

boat fuel gauge

1. Never trust an electric fuel gauge.

Senders are notoriously inaccurate, falsely claiming a tank is quarter full when it's really half full. You could end up overfilling, with a gush of fuel spilling overboard. So be patient, be attentive even when the boat needs a hundred gallons just to top off. The best way to keep track of fuel tank capacity is to rely on an electronic fuel management system. Not only do these gizmos compute mileage and optimal engine rpm, they also keep track of how much gas has flowed out of the tank.

Centek  Fuel Kleen Collar

2. Wrap an oil absorbent collar around the deck fill

For good housekeeping, wrap a collar around the deck fill before poking the nozzle in the hole. Then should a small amount of gasoline escape the special hi-tech fabric will absorb it. I store them on board in a plastic baggy right next to the funnel we'll be talking about later on in this story.

Centek Fuel Kleen collar installed on Nozzle

fuel air separators prevent air bubbles from spilling gasoline

3. Consider installing a fuel recovery system

Fuel air separators prevent air bubbles from spilling gasoline. Should air bubbles percolate up out of the tank the unit will capture any burbling gasoline in a bottle. Some models don't capture the fuel, per se, but instead flow it into an expansion chamber that drains back into the tank.

oil absorbent sheets

4. Sop up gasoline spills with oilzorb sheets

Have oil absorbent sheets readily on hand. Use the kind of oil absorbent sheets intended for keeping oil changes squeaky clean. That way, should a few drops spill on the gel coat, it's an easy matter to absorb the fuel droplets before they cascade down the topsides and into the water. I also use these sheets with the pump nozzle, wiping its nose so to speak, in order to keep droplets from spilling onto my boat or onto the pavement. These sheets absorb 15-20 times their weight in oil related products, not water and float even when saturated.

Just like the previously mentioned fuel collar, I keep one in a double-wrapped plastic baggy so the sheet can be used over and over again without smelling up the boat. Obviously, if the sheet is sopping wet with fuel its better to disposing of it outright.

Racor fuel filter funnel

5. Pre-filtering marine fuel is a wise strategy

Prefilter gasoline to keep junk out of the fuel tank. Use a boat specific funnel with a long constant diameter snout that fits the deck fill like a glove. I prefer one fitted with a series of progressively tighter weave mesh screens that keep gravel and other larger particulate matter out of the fuel supply. Some models incorporate a water separator, keeping gas dry. Funnels come in different sizes, the bigger the funnel the faster it flows fuel. Even a cheap funnel with a simple mesh screen is better than nothing.

Alcohol-Fuel-Problems cover foto

How to Solve
Alcohol Fuel Problems
in Boats

Learn How to Best Use Fuel Filter Funnels and Additives to Remedy Alcohol Fuel issues

Fueling a motor boat, an electrical generator or a personal watercraft with ethanol isn't a problem when you know the secret to keeping the engine happy.

By now you already know that Ethanol-laced gasoline is notorious for causing big problems with outboard motors, stern drives and inboard engines. Whether or not it should ever put to sea is a moot point. Whether we like it or not, that's what's on the fuel docks. But the fact of the matter is that boat and personal watercraft owners need not suffer. In fact, millions of boaters burn E-10 without problems. Here's how to make this BioFuel work for you.

The author is a factory-trained marine mechanic and service manager who, as a contributing editor, wrote about marine engine technology and repairs for Motor Boating magazine for three decades as well as contributing stories to Popular Mechanics, and various Boating and Yachting magazines in the US, Australia, Singapore and Brazil. He has plied the trade in the Caribbean, Iowa, Arizona and California.

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