Ethanol additive

[tacx]

I'm confused on the issue of ethanol additives we put in our boat fuels. My daughter bought a boat and asked me " if we have to put ethanol additives in our boat engines, why don't we have to put it in our cars?" I couldn't answer her.
So why?
Tom

 

[Scott Danforth]

not sure what you are putting in your motor.

 

[dingbat]

Becouse a marketing department said so

E-10 is the best fuel system cleaner on the market

 

[b.gagnon]

It's not much of an issue if the boat doesn't sit unused much. The alcohol sucks water from the air and causes the fuel to gel up. The biggest problem is if you have an old motor that was not designed to run with ethanol in the fuel. The fuel lines and fuel pump's get eaten by the ethanol (additives don't help with this). Also if you have a fiberglass fuel tank it will need to be replaced.

 

[briangcc]

Stabil makes a stabilizer for ethanol gas. Usually use this while boat is layed up for storage.


That being said, my year old boat specifically calls for ethanol free gas. I believe there's a sticker right on the gas cap and I think it's either no E-15 or E-10. As its under factory warranty and there's a couple gas stations close by that sell ethanol free gas that's all it'll run on during my ownership.

I ran regular 87 octane gas through my Four Winns while I owned it and towards the end the marina was telling me I had debris in the fuel filter. Probably direct result of the ethanol eating away the fuel lines. Offloaded the boat before I had to deal with a major repair bill.

 

[oldjeep]

I'm confused on the issue of ethanol additives we put in our boat fuels. My daughter bought a boat and asked me " if we have to put ethanol additives in our boat engines, why don't we have to put it in our cars?" I couldn't answer her.
So why?
Tom

It must feel good to have raised a daughter smarter than you

 

[BRICH1260]

Like said above, not much of an issue if you are going to burn the fuel off soon. Its only an issue when the fuel will sit for prolonged periods. It`s probably assumed that gas in a car will be burnt up fairly quickly.

 

[high&dry]

The additives are used because boats sit for often long periods between use. The ethanol can (and will) absorb moisture and phase separate from the gasoline. Then it causes a mess with the fuel system and can damage the engine, fuel system. Even gasoline without ethanol needs a stabilizer for storage or off use time.
H&D

 

[jkust]

Pretty much I use the standard e87 in my boats without issue. Have had plenty of issues with carburetor based machines like snowblowers as well as one of my old sleds that has carbs when I don't summarize properly. I tested for fun last year what happens when I use the 93 octane/ethanol free gas in my waverunner since it is easy to test top speeds with those versus my boat. Our ethanol free gas only comes in 93 octane for which a higher octane than 87 is not beneficial for yamaha sc waverunners. The difference was a constant two mph increase in top speed without ethanol. 70mph with ethanol free vs 68mph with E10. I think the e free gas is about two bucks more per gallon so not really worth the cost just to say I can go 70.

 

[Chris1956]

I am very surprised that any new boat would require alcohol-free gasoline. I thought new US boats (and other vehicles) were required to burn E10.

As far as I know, E15 (and higher alcohol fuels) can only be used safely in select vehicles called Flex-Fuel. I never heard of a flex-fuel boat engine, as those require more sensors then engines that use E10.

 

[NYBo]

The fuel systems in cars are sealed from the atmosphere except to allow air in as fuel is pumped out of the tank. This is not the case except for boats made in the past few years so there is a constant in and out of air as temperatures change. With that air comes water vapor.

 

[high&dry]

My 2004 Mercury Optimax 150 Saltwater is rated for 10% ethanol fuel and runs fine save for a slight reduction in power. This does not negate the need for additives to prevent water accumulation and resulting phase separation of fuel stored in a boat often weeks or months.

If you have an (stored) automobile or seasonal equipment where it is not practical to drain the fuel then you should use the same additives being discussed here.

My Whaler holds 60 gallons of fuel. It is just not practical to drain it so I top it off with no-ethonal fuel but I still use additives like Stabil or Mercury Fuel Treatment #1(I think it is?).

 

[Scott Danforth]

everything in the past 20 years is rated for E10. E15 has no place in small engines, outboards or boat motors.

 

[dingbat]

https://www.epa.gov/sites/production/files/2015-09/documents/waterphs.pdf


Another way water can enter gasoline is through absorption from the air. Water, in the form of water vapor, can dissolve in gasoline. The more humid the air, the faster the water vapor will dissolve in the gasoline. Due to chemical equilibrium, however, assuming a constant temperature, phase separation willnever occur if the only source of water is from the air. Only enough water to saturate the fuel can enter the system, and no more. Water vapor, however, dissolves in gasoline very slowly, even at very high humidity. For example, at a constant temperature of 100 degrees F and relative humidity of 100%, it would take well over 200 days to saturate one gallon of gasoline in an open gasoline can (assuming the only source of water is water vapor from the air). Water absorption from the air is far slower at lower temperatures and humidities. (At a temperature of 70 degrees and relative humidity of 70%, it would take over
two years to saturate one gallon of conventional gasoline in the same gasoline can.) Again, oxygenated gasolines can hold more water than conventional gasoline, and would therefore take much longer to saturate with water.

 

[JimS123]

The alcohol sucks water from the air and causes the fuel to gel up. The biggest problem is if you have an old motor that was not designed to run with ethanol in the fuel. The fuel lines and fuel pump's get eaten by the ethanol (additives don't help with this).

Total nonsense. Ethanol has been in use for 20 years. I have 60 year old motors that run just fine.

Mercury marine recently published a white paper on the subject. It talks about many of the myths.

 

[NYBo]

Another thing to consider is the fuel filler cap. On many boats, it is exposed and horizontal. If the o-ring has deteriorated, water will get into the tank.

 

[Chris1956]

Ethanol-free gasoline does not absorb water. That is why we needed to occasionally use dry-gas in our cars in the 70s and earlier. E10 absorbs this water.

As was mentioned, the obvious cure is to use the boat often, and every time you top off with E10, it will safely absorb any moisture in the fuel, and burn it, on the next boat trip.

Not sure it makes sense to top off tanks with non-ethanol gasoline, as this allows water to build up.

 

[Silvertip]

Engines don't know and could care less whether the fuel has ethanol in it. The rubber parts in the fuel system if not ethanol tolerant is the issue. Worrying about water in the fuel is also a non issue unless the boat is used very infrequently. A water separating fuel filter should take care of that issue as well. Been using ethanol fuels for decades in all my vehicles and yard equipment. My weed whacker is 25 years old and the only issue has been fuel line replacement. Even Tygon gets brittle in gasoline over the years. My Chevy Impala burned E85 whenever the price difference was 35 - 40 cents/gallon. 150,000 on it when I sold it.

 

[high&dry]

Ethanol or not, if you are not draining the fuel then top off before longer storage or off use. I use no ethanal fuel so I top off with no ethanol fuel. A full tank is less like to have condensation as there is no place for moisture laden air to occupy.

In the aviation world, 100LL is still the primary piston aircraft fuel. It definitely has no ethanol in it, lol. Nonetheless we sump our fuel tanks before flight and one might be surprised to see water in the fuel. Keeping the fuel tanks topped helps to prevent what os essentially condensation. With ethanol fuel, that condensation can cause phase separation as the ethanol is hydroscopic.

Frsh ethanol fuel runs fine in my boat, but since we only get a few outings per year and it sits for six months through the winter if we used ethanol fuel, which I have innthe past, phase seperation is real and it has happened to us. I still use Stabil over winter but by not using the ethanol fuel I at least remove that worry from my plate.

 

[Scott Danforth]

Engines don't know and could care less whether the fuel has ethanol in it. The rubber parts in the fuel system if not ethanol tolerant is the issue. Worrying about water in the fuel is also a non issue unless the boat is used very infrequently. A water separating fuel filter should take care of that issue as well. Been using ethanol fuels for decades in all my vehicles and yard equipment. My weed whacker is 25 years old and the only issue has been fuel line replacement. Even Tygon gets brittle in gasoline over the years. My Chevy Impala burned E85 whenever the price difference was 35 - 40 cents/gallon. 150,000 on it when I sold it.

flex fuel engines are different than simple small engines. on a flex fuel engine, the ECU compensates timing and fueling based on the amount of corn squeezings in the fuel. small engines, outboards, etc. go into melt down around 15% ethanol as simple EFI systems and carbs can not adjust.

hence the big old sticker on small engines, outboards, motorcycles, etc up to 10% max.

Kawasaki, Briggs, Subaru, Honda, Ryobi, etc had a bunch of failures a few years back with their motors in outdoor power equipment, specifically in a few specific states. turns out the fuel was close to E20 and being labeled as E10. this is what stirred up OPEI, NMMA, AEMA, AMA, AACA and GIE (among others) to petition the EPA. Many lawsuits followed

comparing your flex-fueled chevy to a marine motor is like comparing tomatoes and peanuts.