Gasoline & Ethanol

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Gasoline & Ethanol

E -10 Gasoline

The RNLI, Sea Tow, USCG and many organizations will tell you that the most calls they get for assistance start by being engine related. They will also tell you that 90% of engine failures are due to Fuel issues. Bad Fuel is not a inconvenience issue it is a safety issue.

Most gasoline users are owners of sport fishing and center console boats that use outboard engines

Latest news of ethanol and gasoline

What is E-10 gasoline and what are the issues.

Increasingly you will find gasoline labeled E-10. This is government mandated to decrease US dependence on foreign oil, and reduce carbon monoxide emissions by 20 %. There is a move afoot to further increase Ethanol levels to 15% which would not be good for the boating industry and boaters as engines are not designed for more than 10% Ethanol. Use this link to find out more

E10, Is a gasoline blended with up to 10 % ethanol alcohol and is now in widespread use in the U.S. Ethanol, ethyl alcohol, is made from corn, sugar and other grains

E-10's use in boats is State dependant. Here is the American coalition for Ethanol site. On the East Coast, MD and VA and points north use E-10 while NC uses pure gasoline. On the West Coast. Hawaii, uses E-10 while the Midwest has been using E-10 for over a decade.

Steps to keep fuel clean

  • Clean Fuel tanks
  • Use clean Fuel
  • Filter Fuel before it gets to engine
  • Stabilize Fuel that's stored or sits idle
  • remove water from Fuel.

The main issues with E-10 are :

The biggest concern is the level of Ethanol in your gas. Outboard motors and gas engines are now warranted by the engine manufacturers to use E-10. However more than 10% can be dangerous to your engine. When you fill up ask what you are getting.

Ethanol attracts water. The water will drop out of the Fuel and settle at the bottom of the tank, (Called Phase Separation) taking the ethanol with it. If the water does not get to the height of the pickup you may not have problems. However when it gets rough, the water gets bounced around and gets sucked up into the engine, now you have a problem.

Ethanol is a excellent solvent, which means it will dissolve many particles and contaminants in your tank and even the tank itself if its fiberglass.

These dissolved particles can find their way to your engine. The answer here is to use a 10 micron fuel filter and check with your engine manufacturer for recommendations.

Older Fiberglass tanks can be a problem. If you suspect your old tanks you may be better off replacing them.

Due to its solvent nature Ethanol can eat away fuel system parts. However since the introduction of E-10, motor manufacturers have come to address these issues. The solvent issues have been addressed by making the fuel system alcohol proof. New engines are now E-10 ready.

In most states (not all) its required by law that pumps pumping E-10 must be labeled

Clean Fuel tanks

Inspect your tank and if you have any doubts clean it. This will get rid of any water and contaminates before you fill up with good fuel.

Clean Fuel tanks

Mobile services are available to clean your tanks. They are commonly know as Fuel polishing services. They come and pump the fuel in your tanks through a filtration system. This can give you clean Fuel at the beginning of the season.

Quality Yacht Services Marine Fuel System is a company based in Florida covering the Florida Keys, that is an example of a tank cleaning service. They will clean gasoline as well as Diesel tanks. Check your local area for a similar service.

Petro scrub offers Fuel tank filtering and cleaning on the east Coast US.

Use clean fuel

Buy Fuel from a reliable source, that you can be confident in. If you have an source unknown to you check the fuel. Pour some fuel in a container and let it settle. Water and dirt will settle to the bottom. If you see either, filter the fuel before it goes into the tank, or better yet, buy your fuel somewhere else.

Or use one of these filters. This is your first defense.

Use clean fuel

West Marine WM-F8C

WM-F8C these filters were tested by Powerboat Reports (March 2003) and rated better than other more expensive funnels. Teflon-coated, stainless-steel filter separates water and dirt from gasoline, diesel and kerosene fuels. Made from industrial standard electro conductive polypropylene that can be grounded for extra safety. Fuel flows quickly through the filter into the tank and water stays in the funnel. Practical-Sailor did a test and found it to be the best despite its low cost. $35.

Fuel Filter Funnels Medium Funnel - 3.5GPM, 8-3/4 inchH x 5-1/2 inchDia., 100 Micron

Use clean fuel

Fast Funnel

Disposable funnel for spill free fueling or oil fill.

The above filters can remove water and solids down to .005 inch but cannot remove emulsified water. For the you will need a turbine type water separator (like the Racor spin on ).

Fuel Filtering

Because Ethanol is a great solvent is going to dissolve many of the contaminants in your tank, maybe even the tank itself. These small particles are going to find their way into your fuel system. Have spare filters.

Its recommended that you install a 10 micron fuel filter. When using E-10 to begin with you may go thru a few filters as the contaminants go thru the system. At some point the tanks will end up clean and you should then be OK.

Fuel Filtering

Check you engine manufacturers recommendations on filtering.

Yamaha 10 micron Fuel filters

Yamaha designed your outboard, and we know what it takes to protect it. Our new 10-Micron Fuel Filters filter out contaminants and separate water from the fuel, ahead of the onboard filters and injectors. They have a high-performance flow rate and a much larger filtering surface than other filters on the market, and they’re manufactured to strict Yamaha standards.

Suzuki, Mercury Marine mercury say all their new outboard engines have the required filters, Evinrude

Fuel Filtering

Fuel filter water separator

Fuel filters are not enough these days and it best to look at a Fuel filter water separator.

Spin-On Series Gasoline Fuel Filter/Water Separators

Racor's famous Aquabloc® filter media separates water into the bottom of the drain bowl and ensures virtually 100% removal of water and solid contaminants. Filters come in different sizes for gasoline engines and any rate of fuel flow. Designed for use on the suction side of pump. All filters feature a die-cast aluminum head which is anodized and painted.

See-thru bowls allow easy visual inspection for water; metal bowls are recommended for use in areas of high heat and are required by the US Coast Guard on gas inboards. Standard filter size is 10 micron. Standard pipe-to-hose barbs are used for installation.

Stabilize and Fuel Storage

Phase separation is the separation of water in fuel and due to the density of water it drops to the bottom of the tank (see right). The problem is if your fuel pickup is in water you are not going far. To guard against phase separation keep tanks full and use a Fuel stabilizer.

Fuel Stabilizers slow phase separation, but will not stop it. If you are in season and are regularly using fuel and refilling your tanks you will not suffer phase separation. Phase separation occurs when fuel sits unused.

Fuel Stabilizers provide stabilizing chemistry and are needed when fuel sits for extended periods. Phase separation (when water separates from the fuel and drags the ethanol with it) typically occurs when tanks are 1/4-1/2 full. So keep the tanks 90-95% full and stabilize.

Check your engine manufacturer for their recommendations. Here is Mercury Marine from the Mercury marine site. What should be done when storing boats with ethanol-blended fuels for extended periods? Mercury Marine Fuel System Treatment & Stabilizer can help maintain fuel systems in storage. It contains oxidation inhibitors to reduce oxidation and gum formation, metal chelating agents to protect metal components from corrosion, water absorbing agents to reduce the presence of free water, and dispersants to help suspend and disperse debris. Mercury Marine fuel system treatment & stabilizer

The best way to prevent phase separation in E-10 is to “keep it dry.

Readily available Fuel Stabilizers at local stores

Valvtect Ethanol Gasoline Treatment

Specially formulated to prevent ethanol and non-ethanol gasoline related problems. ValvTect Marine Gasoline Ethanol Treatment is designed to stabilize fuel up to one year, prevent octane loss, control moisture, prevent phase separation, prevent corrosion, clean up carbon deposits and reduce fuel consumption. 12oz. bottle treats 120 gallons.

Readily available Fuel Stabilizers at local stores


StarTron manufacturers of storage stabilizers for marine fuels, recently introduced Star*Tron.
Star*Tron is an enzyme-based additive for gas or diesel fuels that solves a host of fuel-related problems. Stabilizes gas for short and long term periods of inactivity (up to one year) while preventing the formation of varnish. Eliminates carbon buildup in fuel delivery system and exhaust components. Increases octane and removes water from the fuel, making it the perfect solution to prevent and eliminate ethanol (E-10) fuel problems. Eight ounces treats 128 gallons of gas.

Readily available Fuel Stabilizers at local stores

PRI-G E-10 Gasoline Fuel Treatment

Your boat or RV sits. The fuel goes bad. And you're facing major expenses getting things back in shape. Protect your treasured investment and your pocketbook against the costly effects of fuel system gum and varnish.

Golden Eagle STA-BIL

Fuel stabilizer keeps fuel fresh for quick, easy starts after storage. Removes water to prevent corrosion and cleans carburetors and fuel injectors

STA-BIL Fuel Stabilizer is safe to use in all gasoline's, including gasoline/oil mixtures and ethanol blends (including gasoline with up to 10% ethanol)

Remove Water

We know that if you leave a boat for a long period that you should fill up the fuel tank. This reduces the chance of condensation as there is less room for air. Air forms condensation and the water produced gets into the fuel.

Removing Water

c quip super soaker

CQip wins innovation award for its new Super Soaker a device bag type device that sinks to the bottom of the Fuel tank and soaks up water.

The super soaker absorbs water from beneath the fuel. Tie off the

Remove Water

H20 out

One area where air and condensation can get in is through the fuel tank breather and vent line. This simple vent can let in moist air. You do see people stuffing rags into the vent fitting to stop moist air getting in.

To combat this problem, the h20 out from Pindell Engineering is a high tech filter that eliminate the moisture. The installation is simple as the fitting splices into the vent hose line.

Water separation or phase separation

As we have seen Phase separation occurs when water separates from the fuel and drags the ethanol with it to the bottom of the tank. This typically happens when the water in the fuel gets to be 0.5% or more.

If you have fuel that has sat for 60-90 days and it contains more than the above level of water then the fuel should probably get discarded. To stop this happening keep tanks full, add stabilizers and keep water out or well below that 0.5% level..

If you have suspect Fuel. Pour some fuel in a container and let it settle, the water and contaminants will settle

Marine Development & Research

MDR claims they have tests have shown that MDRs NEWEST PRODUCT, E-ZORB (MDR-574), will totally emulsify the phased separation of water and Ethanol at the bottom of a fuel tank right back into the fuel, allowing it to pass through the finest filters and safely burn through with the fuel. At the same time, the octane lost when the Ethanol went to the bottom of the tank with the water will also be replaced back into the fuel.

Resource Articles on Ethanol

BoatUS article on Ethanol

BOATUS "we have found that once the transition to E-10 is complete and the first few tanks of ethanol enriched fuel are run through the system, the issues with E-10 are manageable" says Bob Adriance, Technical advisor with BoatUS. "we also seen that owners who use their boats frequently and cycle through fuel have less problems than those that are only occasionally used"

Test for levels of Ethanol

To check that the gasoline you use contains no more than 10% ethanol.

Try using this test kit from Fuel Testers.

This test kit can help you understand the level of Ethanol.

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