Choosing the Right Marine Fuel For Your Boat

Fuel for Thought

How to decide the best option for your boat engine?

Different boat engines require different fuels, and as a boat owner, you may be able to choose between a number of options at the pump. Use the wrong fuel, however, and you could end up doing irreparable damage to your boat’s engine as well as its fuel tank. Let’s go over the basic types of fuel you might find when filling up and which ones to use and, more importantly, not use.

E15 Fuel—A Great Way to Ruin Your Boat Engine

Chances are you’ve heard of E15, and it’s becoming more and more popular. But this is the one fuel that you do not want to use to fill up your tank. Most engines built over the last 20 years can and do work with E10 fuel, so it isn’t a surprise that boat owners might believe that E15 will work with their engine as well. Unfortunately, this is a common misconception that can ruin a boat’s engine.

Even the Environmental Protection Agency (EPA) advises against the use of E15 in boat engines. In fact, they’re so worried about it that they’ve forced companies to submit a Model Misfueling Mitigation Plan that must be approved before they can begin selling E15 at their stations.

What will happen if you put E15 in your boat’s engine or fuel tanks? E15 is made up of 15 percent ethanol, and ethanol can be highly corrosive. You’ll end up with deteriorated components and clogged fuel filters. Use the fuel long enough and it will result in fuel leaks and damaged fuel tanks. This is not only harmful to your boat, but it’s also dangerous to the environment. Many trailerable boats are filled up at the gas station, where E15 and now E85 are available and are designed for later-model automobile engines. Make sure to grab the right pump, E10 only, which may not be the same you use for your new truck.

So what type of fuel should you put in your boat? This will depend on your boat’s engine, but here are the main options:

Diesel Fuel
Ethanol-free Gasoline
E10 Fuel
Oil and Gas Mixtures

Diesel Fuel

While there are some new diesel outboard engines on the market, these are rare and your outboard is likely to be a gas engine. On the other hand, if you’ve purchased a larger boat with an inboard motor, you may find yourself with an engine that requires diesel fuel. Diesel fuel is more expensive, but it’s also more efficient. The engines that this fuel powers usually offer much higher torque and horsepower. On top of this, diesel engines tend to be more robust than gas-powered engines so you should get more life (and years) out of them.

Ethanol-free Gasoline

Ethanol-free gasoline does not come with the corrosive effects that gasoline with ethanol has; however, it is more expensive and can often be hard to find. Also, this fuel should not be used in an engine that has been using E10 fuel. The reason is that ethanol-free fuel uses the chemical additive methyl tert-butyl ether (MTBE) as an octane enhancer and to fulfill the oxygenate requirements set by Congress for the Clean Air Act but is now banned in some states. This additive, when combined with ethanol, can lead to clogged fuel filters.

E10 Fuel

When E10 fuel was first introduced into boat motors, it did not do well. This was partially attributed to the fact that E10 was being mixed with MTBE. There were other problems as well, but the main reason was that boat engines just weren’t designed to run on E10 fuel.

Fortunately, this is no longer the case, and E10 is safe for most boat engines. This being said, I’d advise all boat owners to check their owner’s manual before putting any fuel in their boat’s engine.

E10 is currently the easiest fuel to find. It’s also the least expensive, viable fuel that you can use in your boat. Most boat owners who have gas engines will probably use E10 fuel, including those who used ethanol-free gas in the past. When making the switch, be sure to completely remove all of the old fuel from the tanks and the engines, and clean them as well. Taking these steps will greatly reduce the chances of clogged fuel lines and other engine troubles.

Oil and Gas Mixtures

Many boat engines require a special mixture of oil and gas. The oil that is added to this fuel mixture helps lubricate the engine’s moving parts and makes the engine run smoother than a gas-only fuel.

The oil and gas ratios for each engine will vary so check your owner’s manual before creating these mixtures. Choose marine oil for this mixture to get the best performance and longest life out of the engine.

At the end of the day, boat fuel types aren’t too complicated. Read the owner’s manual, and you shouldn’t have any trouble choosing the right fuel for your boat.

By Morten Storgaard, Southern Boating July 2020

Top Three Boat Systems

Every boat owner should know these top three boat systems—and know them well.

Congratulations! You’ve purchased your dream boat, and you’re ready to cruise faraway lands in search of adventure and fruity drinks with little umbrellas in them. Not so fast! Now the real fun begins as you learn about the operation and function of the various equipment on board prior to heading out.

To help boost your maritime learning curve, here are three common boat systems every cruiser should be familiar with.

DC electrical system

When it comes to your boat’s DC electrical system, knowledge is power! Smart boaters will acquaint themselves with major components and how they interact to provide juice to the various systems and equipment on board before problems arise.

Parts to know on sight:

DC system components you should become intimately familiar with include batteries/battery banks, primary on/ off battery switches and the location of any breakers or fuses within the system.

Spare parts to carry and be able to change/fix:

If your DC system utilizes fuses, knowing where they are and having spares for each type (cartridge, spade, etc.) is a must. Read through the owner’s manuals of electrical equipment you have installed (to determine if they come with inline fuses), and don’t forget to carry spares for any unusual or specialty fuses you may need (engine starting, windlass, etc.).

In addition to the tools commonly found in the basic kit, the No. 1 item you’ll want to have on board when troubleshooting your DC system is a multimeter. It’s indispensable for tracing DC voltages, testing fuses and tracking down broken wires or corroded connectors. You don’t need anything fancy, and since they can be found at most hardware stores for as little as $5, there’s no excuse for not having one in your toolkit.

Other good-to-have items are a 15-foot jumper wire with alligator clips on each end (to help troubleshoot wiring circuits), crimpon butt and terminal connectors, wire tripper/crimpers, heat shrink and liquid electrical tape (for sealing connections), WD-40 (or a similar corrosion inhibitor), a small wire brush (for clearing away corrosion), and possibly an assortment of wire (various lengths and sizes).

Fuel system

When fellow cruisers say getting there is half the fun, it’s obvious they’ve never been stranded on the water due to a stalled engine. If it happens, you’ll find getting your boat moving again will be ALL the fun you’re looking for. More often than not, an on-the-water, no-go event will likely involve the fuel system.

Parts to know on sight:

This is another system that you should be able to trace out (from tank fi ll to engine) before problems occur. Components to locate and identify include a fuel tank fill hose and fuel line fittings, fuel shut-off valves and all fuel filters.

Spare parts to carry and be able to change/fix:

Have spare filter cartridges or cartridges for both primary and secondary filters on hand. Familiarity with the requirements for bleeding your diesel after fuel filter changes is also highly recommended. This maintenance item will go much smoother if you know how to do it beforehand.

Sanitation system

With the possible exception of “Where’s all this water coming from?”, probably no other statement strikes more fear in a boat owner’s heart than: “The toilet isn’t working for some reason.” It’s particularly troubling when you realize the issue typically doesn’t make itself known until after “the deed” has already been done.

Parts to know on sight:

This depends on the type of marine sanitation system you have installed. Gravity fed toilets (aka Porta Potti-type units) are pretty simple and work just like the name implies. They have a bowl that essentially dumps its contents directly into an integral holding tank, which can be removed and discarded in the appropriate receptacle on shore.

Permanently mounted sanitation systems will generally have a flushwater intake thru-hull and seacock (although in some cases this may also be plumbed to the boat’s freshwater system), a manual- or electric-flush toilet, a holding tank, and a deck fitting for dockside pumpouts.

Additional components you may see (depending on the system) include “Y” selector valves (allowing you to discharge bowl contents directly overboard or into a holding tank or waste from a holding tank to a macerator or deck pump-out), vented loops (to prevent back siphoning and flooding), a macerator pump, and an overboard discharge thru-hull and seacock.

Spare parts to carry and be able to change/fix:

Spare parts can range from gaskets and seals to entire rebuild kits for the toilet pump. A great place to look for advice on this is the owner’s manual, which will usually provide a suggested list of spare parts. A basic tool kit containing screwdrivers, a socket set, etc., as well as a few extra hose clamps, will also come in handy, particularly if you have to disassemble hose runs to look for clogs—a job that’s just as nasty as it sounds.

By Frank Lanier Southern Boating August 2017

Clean Fuel for Happy Cruising

9 out of 10 problems with diesel engines are the result of contaminated fuel. We’ll show you how to keep your fuel system in tip-top condition.

According to national repair statistics, 9 out of 10 problems associated with diesel engines will be the result of contaminated fuel. Here’s how to keep your fuel system in top condition and avoid becoming a statistic.

One of the major differences between gasoline and diesel engines is the way they use fuel. Gasoline is simply a fuel that’s burned to produce heat and power, but diesel fuel also acts as a lubricant, which is why it feels oily. Diesel engines also circulate more fuel than is needed to produce power. This extra fuel not only helps lubricate the engine but also carries away excess heat.

The key to keeping a diesel engine happy is clean fuel. The reason for all of this clean fuel hubbub has to do with your engine’s fuel injectors. These precision-tuned components deliver a precise, ultra-fine mist into the combustion chamber. They don’t like contaminants, and even microscopic specks of dirt or water can wreak havoc on the combustion process and your injectors.

Fuel filters are the first line of defense. A typical diesel fuel system contains a larger primary filter mounted on a bulkhead near the engine and a smaller secondary filter mounted on the engine itself. The primary filter does the lion’s share of fuel filtration, while the finer mesh secondary unit does the clean-up work by filtering out any microscopic particles of grit and water that make it past the primary. Many diesels will also have a second primary filter plumbed into their fuel system allowing you to change a clogged filter while keeping the engine running.

Primary filters should have a clear sediment bowl and allow you to visually check for water or sediment—part of your daily routine while cruising.

Fuel filters should be changed when dirty but prior to affecting engine performance. This can be accomplished by replacing filters at regular intervals—X number of hours or annually, for example. A more accurate way to monitor filter performance, however, is by installing a vacuum gauge at the primary filter. This provides a visual representation of fuel flow restriction through the primary filter or conversely, how hard it is for the engine to suck fuel through it. The higher the gauge pressure, the more clogged the filter is and the more pertinent the need for replacement. To help keep bad fuel from entering your tank in the first place, use a multi-stage fuel filter funnel when taking on clean fuel. Popular examples of these include the Racor Fuel Filter Funnel (ph.parker.com/us/en/fuel-filter-funnel) or “Mr. Funnel” (mrfunnel.com).

Even with your fancy new filter funnel and other such precautions, the best option is always to purchase the cleanest fuel possible. Choose marinas that have a high rate of clean fuel sales and thus, fuel turnover. One of the best marinas I’ve ever seen in this regard was located beside a major highway and also served as a truck stop. If you have any doubts about the cleanliness of the fuel down at the Rake ‘n’ Scrape Fritter Shack and Marina, pump some into a clean glass jar before fueling and let it sit a few minutes to see if any water and dirt settle to the bottom. If you see either, buy your fuel somewhere else.

But buying clean fuel is only half the battle. Two of your biggest enemies in the battle for clean fuel are water contamination once on board and during long-term storage. Diesels use pressure to generate combustion, and when water enters the engine it turns to steam, which has the potential to blow your injectors to pieces. Water also mixes with the sulfur in your fuel to create sulfuric acid, which can cause internal engine parts to corrode.

So how does water get into your fuel tank? One way is through the tank’s vent system. Unlike the closed fuel system in your car, a boat’s tank is vented. This open system lets moisture in where it can condense on the inside walls of your tank due to daily heating and cooling cycles. The more air you have in your tank, the more moisture and potential condensation. To combat this, the recommendation is to keep your fuel tank fully topped off (up to 95 percent), particularly during long-term storage. Another common point of entry is your fuel tank deck fill due to damaged or missing O-rings. Fuel fills located on side decks are especially vulnerable in this regard (particularly on sailboats) as they can ship a lot of water during rough passages, heavy rains or even during wash downs.

As water enters your fuel tank it eventually separates and settles to the bottom, a common problem with long-term stored fuel. That’s when it gets buggy. Microbes thrive in this water and their only goal in life is to eat and multiply. Sure, you can add biocides after the fact and kill them, but the problem lies in disposing of them afterward. In the case of dead microbes, they’ll lie in wait at the bottom of your tank until that first rough passage and then rise up zombie-like to clog filters and wreak vengeance on your fuel system or worse still, your engine. The best strategy (particularly for long-term storage) is to treat your clean fuel with stabilizers and biocides before a bug issue occurs, and prevent water from entering your tank in the first place. No water, no critters.

Fuel Storage

Don’t Fuel Around.

Oil is the result of decaying matter of once-living organisms compacted over untold tens of millions of years. As layer upon layer of sediment settled one on top of the other, the increasing pressure and the ensuing rising temperatures produced a chemical change whereby the remains—way too complex to discuss here—were transformed into the raw material that would eventually lead to petroleum. Most boat owners are savvy enough to chart their necessary fuel-ups with plenty of reserve built in. But if you enjoy covering long distances and do not have the proper tankage—or do not trust the quality of the fuel in a certain port of call—you might consider carrying bladder tanks to store your extra fuel.

“Not all fuel bladders are created equal,” says David Dack, VP of sales for Aero Tec Laboratories (ATL), a company specializing in flexible containment technology. “First off, always look for the best quality possible. Money should be no object with this equipment. The one thing you do not want to deal with when carrying volatile diesel fuel or gasoline is an inferior product.” ATL manufacturers bladders constructed from rugged, military-spec, rubberized fabric equipped with such built-in safety features as pressure relief and anti-backflow valves. “The former prevents any pressure build-up as the fuel expands, for example, with the bladder sitting in the sun in the cockpit. The latter prevents any back-spill while taking on fuel.” Ease of use is a primary concern as well. Make sure you position the tank(s) so the weight is evenly distributed as not to throw your boat off. “The bladder must be firmly fastened to the deck with a tie-down kit that is secured over the stand pipe and then ratcheted down. We suggest using a cargo net as an added security measure in case of rough seas,” Dack recommends. “Bladders are most stable when completely full and can be easily rolled up or folded and tucked away within a vented compartment.”

ATL manufacturers bladders constructed from rugged, military-spec, rubberized fabric equipped with such built-in safety features as pressure relief and anti-backflow valves

With ATL equipment, a half-inch brass ball valve assembly with a composite hose barb fitting is standard, with an optional one-inch ball valve for those who are looking for faster fuel transfer. Reinforced hose is then slipped over the barbed fitting on the outlet while the other end is run into the vessel’s main tank. A siphon or gravity feed is then initiated to start the flow of fuel from the bladder to the main tank. Alternatively, an explosion-proof pump may be used to transfer the contents of the bladder to the boat’s main tank. “We also offer our space-saving FueLocker™ design not only for those whose deck space is limited but also to maximize those areas where traditional pillow type of tanks can take up lots more real estate,” Dack suggests.

If you boat seasonally you will want to pay special attention to the fuel in your tanks when preparing for winter lay up. “For inboard gasoline or diesel boats, and with all the issues concerning ethanol, we add a fuel stabilizer and top off the tanks to minimize the chance of any water condensation from happening, which stimulates biological growth and corrosion.” says Dan Cordano, Service Manager for the Suntex Liberty Landing Marina in Jersey City, New Jersey. For outboards with small portable fuel tanks, Cordano suggests running the engine until it stalls out before putting it away. With those portable tanks, he suggests making sure you use the familiar red plastic for gasoline and yellow for diesel to avoid any confusion.

“Besides the inherent nature of fuel degrading over time, boats have a vented system and the possibility of introducing water, whether during seasonal storage or not, is always a problem. You want to do whatever you can to avoid that situation,” says Janis Grundman, National Sales Manager for Technol, a company specializing in fuel stabilizers. “Make sure of your fuel source, keep your tanks topped off whenever possible, and use a stabilizer during those lay-up times. Using an additive during regular operating times will help to prevent any engine problems. And always follow the manufacturers’ recommendations for the amount to use per gallon.”

Until we figure out a better way to power our boats, perhaps with solar, wind, electric, another energy source, or a combination thereof, taking the proper precautions and getting the best out of our fuel systems will keep your boat running smoothly and safely.

By Ken Kreisler, Southern Boating July 2014

DieselFusion Additive

DieselFusion is a fuel additive that utilizes nano-technology to enhance marine fuels and protect vital engine components. DieselFusion dramatically reduces exhaust soot and fumes up to 80 percent and increases fuel economy up to 18 percent while extending engine life. This non-hazardous, eco-friendly product delivers a higher level of engine efficiency, so you can explore with confidence. Available in pints and gallons, a pint of DieselFusion treats 640 gallons of diesel fuel with fuel cost savings starting 30 minutes after dosing. MSRP starts at $59.95 per pint; Contact DavidSHalcomb@gmail.com or call (262) 914-7002.

Southern Boating January 2014