Alcoholic Mercury Outboard

[Speedy]

Here is an itch I’ve been meaning to scratch… Regarding not using Ethanol gasoline in my Mercury 90 HP outboard, because it has alcohol in it. But rather find a gasoline that is Ethanol/alcohol free. I have been told by previous owner, Mercury owner’s manual and local marina operators…So I only use the preferred Ethanol free fuel (High Test), which costs $1.25 a gallon more. No problem. Here is the rub. I’m again told by the same sources that I should always install a bottle or two of Stabil to winterize the fuel tank for the winter...It’s alcohol.  SO…Is alcohol Good or Not Good? I used to run 100% alcohol in my Gasser drag race cars but never in the winter. I might have even taken a little alcohol myself while watching a football game on TV.  Now that it is slightly cooler outside...What does the jury say? Alcoholic Mercury or not?

Speedy

[rolmops]

The answer is simple. It is a myth that there is alcohol in Stabil.

These are the ingredients in Stabil

• Distillates (petroleum), hydrotreated light (64742-47-8)
• Naphthalene (91-20-3)
• Ethylene glycol monobutyl ether (111-76-2)

Edited January 20 by rolmops

[stinger]

I have a Mercury 115hp four stroke that I bought new in 2002 and a Merc 9.9 four stroke kicker new in 2006. I've been using regular 87 octane ethanol gas ever since I owned these engines without any problems. I use marine version stabile at every time I fuel up and double it on my last fishing trip of the season before winter storage. There is usually anywhere from 10 to 20 gallons of fuel in the tank over the winter. My boat has a 48 gallon plastic translucent fuel tank. In the spring when I bring the boat out of storage and before I fire up the engines I siphon out about gallon of fuel from the bottom of the tank into a clear or glass bottle to check for any deposits, water or gunk. The results are very little foreign substances in the bottom of the tank. Using muffs the engines fire right up. I don't have any science or big words that I can't spell behind this post. Just results that I have experienced the last twenty one years with these two engines.

Edited January 20 by stinger

[Andre wallyandre]

I use what is recommended by Mercury. They know their stuff better then us.

[Andre wallyandre]

This should pretty much answer all of your questions on Ethanol.

Mercury Marine remains very active in developing a thorough understanding of important issues and environments in which our products must operate. Mercury’s engineers work constantly to expand our understanding of fuel technologies and their interactions with all Mercury products to ensure they perform properly and reliably. Mercury personnel work in concert with industry groups, such as the National Marine Manufacturers Association (NMMA), to offer input into the overall processes by which many decisions are made regarding fuel regulations and energy policies so future problems are minimized and future developments are beneficial to those who utilize our products.

Included below is a list of questions and answers that address typical concerns of consumers.

Please feel free to contact any Mercury Marine field representative with questions, or contact us at [email protected]. Mercury will do its best to help find answers, whether you’re seeking general information or wishing to discuss legal proposals, or if you’re seeking information regarding ethanol-tolerant materials.

1. What are ethanol and ethanol-blended fuels?
Ethanol for fuel is highly refined beverage (grain) alcohol, approximately 200 proof, that can be produced from natural products such as corn, sugar cane and wheat. New technology will allow ethanol to be made from “cellulosic” feedstocks including corn stalks, grain straw, paper, pulp, wood chips, municipal waste, switchgrass and other sources. Ethanol used for fuel has been “denatured,” or rendered unsafe to drink by the addition of a hydrocarbon (usually gasoline). The ethanol-blended fuel E-10 refers to fuel that contains 10 percent ethanol and 90 percent gasoline. Similarly, E-85 refers to fuel that contains 85 percent ethanol and 15 percent gasoline. E-85 is intended only for engines specially designed to accept high-ethanol content fuel blends, such as the Flexible Fuel Vehicles (FFV) made by some car companies.

2. How is ethanol made?
In the U.S., ethanol is typically produced by removing the starch or sugar portion of corn and fermenting it. The fermented starch is then distilled into alcohol. Excess water is removed, resulting in very pure – 200 proof – ethyl alcohol (ethanol).
In some parts of the world, ethanol is made from a variety of raw materials. For example, sugar cane is used to produce ethanol in Brazil, while sugar beets and wheat straw are commonly used in Europe.
3. What are the characteristics of ethanol?
Ethanol is an oxygenated hydrocarbon compound that has a high octane rating and therefore is useful in increasing the octane level of unleaded gasoline. The EPA, the agency responsible for setting some of the requirements for all gasoline used in the U.S., has allowed the use of ethanol in gasoline at levels up to 10 percent as an octane enhancer and to provide beneficial clean-burning combustion characteristics that help improve some emissions.
Ethanol is hygroscopic (it has an attraction for water) and will more readily mix with water than with gasoline. It has different solvency behaviors than does gasoline, which allows it to loosen rust and debris that might lay undisturbed in fuel systems. And it can more readily remove plasticizers and resins from certain plastic materials that might not be affected by gasoline alone. Loose debris will plug filters and can interfere with engine operation. Additionally, ethanol is corrosive to some metals, especially in combination with water. Although gasoline does not conduct electricity well, ethanol has an appreciable capability to conduct electricity and therefore can promote galvanic corrosion.
4. What is MTBE and why is it being replaced?
MTBE is the chemical shorthand description for methyl tertiary-butyl ether. MTBE is another oxygenated hydrocarbon compound that has a high octane rating. It was initially a preferred compound widely used for octane enhancement as a replacement for leaded compounds in gasoline. When the EPA developed regulations requiring oxygenated gasoline to help reduce smog in several areas of the country, MTBE was the most commonly used compound to supply the additional oxygen, while ethanol was chosen for this purpose in the Midwest region of the country. Recently, most states have banned the use of MTBE because of its tendency to work its way into ground water systems, usually from leaks and spills, as an undesirable contaminant. Ethanol is being used as a replacement.

5. Does ethanol affect horsepower or fuel-efficiency?
Ethanol has a heating value of 76,000 BTU per gallon, which is approximately 30 percent less than gasoline’s heating value (which is approximately 109,000 to 119,000 BTU/gal). The result is E-10 gasoline which should yield slightly lower mileage – a decrease of approximately 3 percent. Fuels containing higher levels of ethanol will have a corresponding reduction in mileage. For example, E85 fuels produce mileage approximately 30 percent less than gasoline.
The octane rating of pure ethanol (200 proof) is about 100 and is therefore useful in elevating the octane value of gasoline. In E-10 blends the presence of ethanol provides about 2.5 to 3 percent of the overall octane rating. The effect on engine horsepower is determined by the octane result of the blended fuel. Care should be taken to select fuels having the octane rating recommended for the engine as indicated in the owner’s manual for proper operation.
Compatibility with Mercury Engines
6. Are Mercury engines compatible with ethanol fuels?
The fuel-system components of Mercury engines will withstand up to 10 percent alcohol content in gasoline – the maximum level currently allowed by the EPA in the U.S. There are some efforts to establish E-20 (20 percent ethanol mixed with 80 gasoline) for use in some areas, but that will require agreement from EPA to grant a waiver. Part of the EPA waiver process will require verification from studies that demonstrate that higher levels of ethanol do not create problems with fuel-system materials or operation of hardware. E-20 has not been extensively studied by Mercury and is not acceptable for use in Mercury products. E-85 fuels must not be used in any Mercury engines and could seriously damage current Mercury products. It is not legal in the U.S. to market any ethanol fuel as gasoline if it contains more than 10 percent ethanol.
7. Will the use of fuels containing ethanol void my engine warranty?
Fuels containing up to 10 percent ethanol are considered acceptable for use in Mercury engines. Fuels containing higher levels of ethanol are not considered acceptable for use, and the use of fuels containing ethanol higher than 10 percent can void the warranty.

8. What about the fuel-system components on the boat?
It is important to follow boat manufacturers’ recommendations when selecting appropriate fuels. Use of an inappropriate fuel can result in damage to the engine and boat components that may require repair or replacement. Fuels with ethanol can attack some fuel-system components, such as tanks and lines, if they are not made from acceptable ethanol-compatible materials. This can lead to operational problems or safety issues such as clogged filters, leaks or engine damage.
9. Can ethanol-blended fuels affect the performance of two-stroke engines?
Two-stroke outboards should experience little or no decrease in performance due to gasoline fuels containing up to 10-percent ethanol when operated according to Mercury’s standard recommendations. When gasoline with ethanol is used for the first time after a fuel changeover from MTBE, the tank must be completely dry prior to introduction of gasoline with ethanol. Otherwise, phase separation could occur that could cause filter plugging or damage to the engine. If an engine is a 1990 or older model frequent inspections of all fuel-system components are advised to identify any signs of leakage, softening, hardening, swelling or corrosion. If any sign of leakage or deterioration is observed, replacement of the affected components is required before further operation.
10. How does ethanol affect my fiberglass fuel tank?
Fiberglass tanks manufactured prior to 1991 may not be compatible with gasoline containing ethanol. It has been reported that, in the presence of ethanol, some resins may be drawn out of fiberglass and carried into the engine where severe damage could occur. If an older fiberglass tank is used, check with the manufacturer to determine if gasoline with ethanol can be safely used.
11. Are older fuel lines prone to failure? What about gaskets?
During the 1980s, many rubber components for use in fuel systems were developed to withstand exposure to fuels containing ethanol. If rubber components in a fuel system are suspected to be of this vintage or older it may be advisable to replace them with newer ethanol-safe components before using fuels containing ethanol. Check with the manufacturer for advice or frequently inspect these fuel-system components for signs of swelling or deterioration and replace if problems are noted.

Recommended Practices

12. Ethanol is replacing MTBE in my region? What should I do?

Before gasoline with ethanol is introduced to your fuel tank, ask your boat manufacturer if any special precautions should be considered with the use of fuel containing ethanol. Check for the presence of water in the fuel tank. If any is found, remove all water and dry the tank completely. As a precaution, it is advisable to carry a few extra filters in case filter plugging becomes a problem during boating.

13. Should I add an additional fine-micron filter to the system to prevent debris from entering the engine?

The addition of another filter to the system will create another possible flow restriction that can starve the engine of fuel. Mercury already provides the appropriate level of filtration to protect the engine from debris.

14. How can a marina prepare for the change from MTBE to ethanol as the fuel oxygenate?

Check with the manufacturer to make certain the tank and lines won’t experience problems with ethanol. Inspect the tank for water and, if present, pump out all water and thoroughly clean the tank. Install ethanol-compatible filters. The tank should be less than 20 percent full before adding the first load of fuel with ethanol.

15. What is phase separation, and how do I deal with it?

If significant amounts of water are present in a fuel tank with gasoline that contains ethanol, the water will be drawn into the fuel until the saturation point is reached for the three-component mixture of water + gasoline + ethanol. Beyond this level of water, phase separation could cause most of the ethanol and water to separate from the bulk fuel and drop to the bottom of the tank, leaving gasoline with a significantly reduced level of ethanol in the upper phase (see Figure 1 below). If the lower phase of water and ethanol is large enough to reach the fuel inlet, it could be pumped directly to the engine and cause significant problems. Even if the ethanol water phase at the bottom of the tank is not drawn into the fuel inlet, the reduced ethanol level of the fuel reduces the octane rating by as much as 3 octane numbers, which could result in engine problems.

The level at which phase separation can occur is determined by a number of variables, including the amount of ethanol, the composition of the fuel, the temperature of the environment and the presence of contaminants. It is very important (A) that the system is inspected for significant quantities of water in the tank before using gasoline with ethanol and (B) to limit exposure of the fuel tank to excess water. If phase separation has occurred, it is necessary to completely remove all free water from the system and replace the fuel before continuing operation. Otherwise, engine problems could occur.



Figure 1: Sample of fuel from fuel tank in which phase separation
has occurred. The upper phase is gasoline with a reduced level
of ethanol. The lower level is a mixture of ethanol and water.

16. Is an additive available that can prevent phase separation?

There is no practical additive that can prevent phase separation from occurring. The only practical solution is to keep water from accumulating in the tank in the first place.

17. Are there any additives that can allow the phase-separated mixture to remix when added to the fuel tank?

No, the only way to avoid further problems is to remove the water, dispose of the depleted fuel, clean the tank and start with a fresh, dry load of fuel.


18. Is there a simple solution to water condensation in the tank as a result of ethanol?

It is best to maintain a full tank of fuel when the engine is not in use. This will reduce the void space above the fuel and will reduce the flow of air in and out of the tank with changes in temperature. This will reduce condensation on the internal walls of the tank and will limit exposure of the ethanol in the fuel to humidity and condensation.

19. What should be done when storing boats with ethanol-blended fuels for extended periods?

When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the temperature cycles up and down. This condensation potentially becomes a problem. 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. It is best used by adding to the tank at the recommended dosage, running the engine for 10 minutes to allow the system to be cleaned, shutting off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, topping off the tank until it’s full, and capping any openings to reduce the amount of exchange with the air that might bring in condensation.

[Andre wallyandre]

Make your fuel selections based on the following criteria, IN THE FOLLOWING ORDER:

-High Traffic, Top-Tier (Name Brand) Fuel
-Appropriate Octane Rating (see above info)
-Lowest possible ethanol content (NEVER to exceed 10%).
-While it may be preferable to utilize a fuel that contains lower (or no) ethanol, use of fuels that are SUBSTANTIALLY higher octane can result in decreased performance, decreased fuel economy, and potential for carbon buildup. Higher octane fuels burn SLOWER and COOLER.

[fisherdude]

I used 87 octane with ethanol and the red stable for years .I ended up with this. 

Edited January 20 by fisherdude

[Speedy]

First…THANK YOU ALL for the many expert opinions and advice! Remember as kids we were told by Dad, ”Don’t do that”. When we asked WHY? The answer was because I said so.

Now I know WHY or WHY NOT answers to fuel winter storage with correct intelligent descriptions.  What made me think about this subject was while I was painting my 3,500 sq. ft of roof with white rubberized paint getting ready to sell my Tucson, AZ house, I was Thinking which was more fun…painting a roof with white paint in the sun or shoveling the white snow off a roof in the cold. Either way my back hurts. LOL

Stay warm you guys and thanks again…Be there soon to my “Forever House” in Vermont.

Speedy

[chowder]

I do what Hank at L&M tells me to do…

[sherman brown]

Ethanol-free gas isn't around where I live so I always have used gas with ethanol in it in everything I have owned in my 45 or so years I've been boating and the only problem I've had was the old gas lines going bad. I haven't lost any of my outboards or Mercruiser motors that I've owned. I used the old Mercury 115 tower of power inline 6 for 25 years and it was still running until I bought a boat that had a 115 Johnson.

 

up until my oldest son and I bought a used 26' Sylvan boat the only time I bought marina gas was while playing in the water. the only place we use the 26' boat is at Geneva Ohio fishing for walleye. now we dock the boat and use marina gas.

Edited January 20 by sherman brown

[Speedy]

Again Thanks for the advice. Reminds me of one of my racing experiences when in the pits while I was being towed to the starting line, my gas generator in my pits ran out. A crew member next to us did me a favor and went in my open trailer and filled the generator for me and re-started it. When I got back 15 minutes later, everyone was upset. Shut the stinky thing off! Seems the nice guy filled my generator with Alcohol/Methanol.

All my gas cans looked alike. Lesson learned. MARK every can with what is in it, even use different colors. Grandpa always said,  ”Don’t mix your alcohol (drinks)” LOL

“Tight Lines” and stay off thin ice.

Speedy

[13owhunter]

I use regular 87 octane in my boat and marine stabil in every tank.  Stabil works....  I top it off with fresh fuel at the end of the season and am confident that I will not have any fuel related issues come spring.  All my 4 stroke equipment gets regular fuel and I run stabil in the fall for the off season.  I have had a total of zero issues due to fuel and I burn quite a bit more fuel than the average guy.  I do put ethanol free fuel in my 2 stoke equipment but i only run through 5 or 6 gallons a year so it doesnt cost a whole lot to do so.

[rolmops]

There is a lot of misinformation and generalization on the gas front. First of all, do you have a big tank that sits in your boat? By all means go ethanol free because it is is in these bigger tanks that the ethanol will attract water and it will just slowly gather until it causes a problem.. Do you use 6 or 5 gallon removable tanks? You can use ethanol gas as long as you empty out your tanks at the end of the season. (stick it in your car tank and yes, you can dump 2 stroke gas in your car too. Just do it in small portions like a gallon  or two at a time with each tank. It does not hurt the engine and it solves the disposal problem.

Is your boat pre 2000? You must change out all your fuel hoses because the hoses used before 2000  will be eaten by the ethanol and start leaking. The same goes for fiberglas fuel tanks. The ethanol will melt the glue that was used to glue them together.

Trailered boats usually have less of a problem compared to boats that lay in a slip. That is because the humidity by the slipped boats is much higher than the humidity next to your house or garag

 Personally, I never use stabil because there are better products on the market. I prefer a product called  "seafoam" because it not only treats the gas,it also cleans the carburetors.

[Speedy]

My fuel concerns began when my I brought my 1987 Sea Nymph, which I had just purchased a few weeks before, to the local Mercury Marine dealer for a full Spring Tune-up. I had to leave VT and return to AZ. But I stored it in my weather-tight garage and I added a bottle of Stabil as advised.  When I brought it to them they called me a few days later with bad news. Said the fuel tank was rusted and had a lot of water in it and it would have to be drained and then replaced. Seems Vermont has a Environmental Code for disposing of waste fuel and oil (I understand, OK) and I was charged $125.00 to empty the tank. They tried and couldn’t find a new replacement tank. I was stuck in AZ so I had no choice but let them find a cure.  When I returned I took the boat back and tried myself to locate a new stock replacement tank. I reached out to the guy in NY who had owned the boat years ago. He had tank problems and replaced it with a new 30 gallon plastic translucent fuel tank designed for Farm storage. He had also replaced all the full lines and fittings and installed the new tank front to back instead of side wards. Then the “Light Bulb” flashed...plastic doesn’t rust; Do this project yourself. The local NAPA auto parts store manager sold me the Stabil and told me that it was good for fuel storage because it contained a lot of Alcohol along with other chemicals to keep and water/condensation from freezing. Another Light Bulb went off. LOL   So I lost my first season messing with this and Vermont’s flooding.

A few of you guys mentioned Seafoam. I have used it many years ago on frozen/rusted/stuck motors that wouldn’t turn over even with a long wrench. Poured the Seafoam in the sparkplug holes and over the old rocker arms and let it set for half hour. Twice it worked, once on an old Model T Ford and another in a well driller’s rig stuck in the field. But once we freed the motor’s drive train and let it run full temp for a while, we then drained it all and installed new oil and filter. Never hear it as a fuel additive to remove water.  But I believe.

Having spent several decades in NHRA drag racing and USAC Indy Car we only used certified Menthol/Alcohol and Nitro Methane. Used products like Power Plus made by Red Line Oil and Benol made by Castrol Oil. Both blended with all types of Alcohol, Nitro and Gasoline fuels. We used a “Paste” on a wooden dowel to dip into the 55 gallon drums of fuel to check for water. But that was high performance automotive engines and not marine. As far as starting cold motors we use spray regular grade pump gas, not high test directly into our injector. Regular would light-off easier when priming our 4,000 HP blown alcohol Hemis. But High test gasoline does made more horse power than regular, ask any Corvette or Ferrari owner what they use.

Again thanks for all the advice; I’m the rookie with boats like this. I did replace the special marine fuel gauge the dealer couldn’t get with a new Stewart Warner Hot Rod gauge from my shelf.   12 volts is 12 volts.

 No Hocus Pocus.  LOL

Speedy

[rolmops]

Seafoam does not remove water. It prevents it from forming in the tank. If you want to remove water there is another product. I think it is called drygas. I never used so I have no opinion about it.

[Speedy]

Thanks again for your input information. I forgot to mention that I did install a can of Dry Gas along with the Stabil in both the boat fuel tank and my Chevy Tahoe sitting next to it in the garage. I think all is good.

Can't wait till Spring.

Tight Lines

Speedy

[muskiedreams]

I have always used 87 octane in my 1990 Grumman with a 1990 75hp Mercury and 1995 15hp 4stroke Evenrude. I bought the boat used in 1996. I trailer the boat and have mostly been in the habit of keeping the tank full when not in use. In winter I add marine stabilizer. I have recently replaced all the small plastic fuel and oil lines inside the 90hp motor. I rebuilt the carbs many years ago but it didn't solve the problem at the time which turned out to be a weak spark issue. I also recently replaced the fuel line between the fuel tank in the bow and the motors BC it was leaking fumes.

 

Since I trailer the boat, every time I use it the fuel in the tank gets mixed up on the way to the launch. So any stratification that may have existed is eliminated before I run the engines. Also, since I don't keep it on the water, there is less opportunity for water to be absorbed from the air since the boat is mostly kept away from the water where there is more humidity during changes in temperature. If the boat is kept on the water with a partially full tank that has vents to avoid pressure changes, every time there is a change in temperature the tank breathes in humid air, the ethanol will absorb it and sink to the bottom. Over time it will build up. Especially over a season with multiple fuel-ups. That is when you really run into trouble. So docking all the time with low fuel level increases the amount of air in the tank and therefore with a large amount of air in the tank each expansion and contraction cycle will draw in a larger amount of moisture into the system. So IMO it is more of a problem for boats that are on the water all season and when the tanks are not kept topped off.

[rolmops]

On 1/22/2024 at 11:00 AM, Speedy said:

Thanks again for your input information. I forgot to mention that I did install a can of Dry Gas along with the Stabil in both the boat fuel tank and my Chevy Tahoe sitting next to it in the garage. I think all is good.

Can't wait till Spring.

Tight Lines

Speedy

Dry gas usually is based on alcohol.  It does what ethanol does. You should use drygas in 2 cases.

First ,when you know that you have water in your tank and do not want it to freeze. That way you prevent small drops of ice to clog up your injectors/carburetors.

Second, when you know there is water in the tank, dump the drygas in there so the water will get absorbed into the gasoline just before you use your vehicle

If you had to use drygas because of one of these reasons , you should run your tank as low as you can without getting stuck then replace your or empty out your water/fuel separator and start with fresh clean fuel

 I once tilted my boat/trailer as steep as possible so all the water and gunk in the tank made its way to the fuel pickup. and pumped all this gunk out through a clear plastic hose into a large glass bottle I kept on pumping until only gasoline came out of the hose.