10% ethanol fuel vs ethanol free fuel for boat/outboard motor use?

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Nov 18, 2020
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In previous years i always ran what we in europe call E0 fuel which is octane 98 gasoline with 0% ethanol, this because i know that this is easier on the fuel lines/gaskets and does not attract moist or leave behind residue as much as E10 which is the regular octane 95 with the legal requirement of 10% ethanol for emissions(scam).

However with the recent rise in fuel prices and even normal E10 fuel rising above 2 euros a litre i decided to now switch to the cheaper E10, this because it was more like peace of mind to run the simple carburated 2008 Honda hp 20 4 stroke outboard 380cc 2 cylinder on the fuel more or less designed for modern turbo cars with the higher octane rating, in theory this motor as a normaly aspirated motor should benefit from a lower octane fuel.

My only concerns are:
- Because ethanol is hydroscopic the fuel absorbs moisture from the air, all modern cars have vacuum sealed fuel system/tank so that is not a problem. However my boat just has a oem plastic 25l tank with a vent screw on the cap. The tank is in outside air/rain etc.. and is not covered. i can not close the valve because i tried this before but if the sun kicks in it almost explodes because of the pressure build up:ROFLMAO:

- My honda owners manual says that the system is designed to run max 10% ethanol fuel, i use the boat a lot and eventhough it doesnt consume a lot its more or less empty every month so i dont see the deteriorating of the ethanol as hazard like it is with a lot of classic vehicles.

-Outboard motors run at lower water/oil temps and eventhough my engine sees a lot of hours at full throttle 25 knts the nr1 problem with (carburated) outboards is fuel diluition at (cold)trawling speeds which is invitable. Last year my oil also came out pitch black like it came out of a 15k oci diesel engine oil change and smelt like gasoline.
Will the ethanol/fuel in the oil be a reason for problems because the motor spends its life in such a humid enviroment? I mean problems that can be created by the ethanol.

Let me know if you have any experience on this topic and if theres something i am missing out on.

-Powerwise do you think there will be any (marginal) difference? This is not a 2.5 bar boost world rally car but a carburated 380cc 2 cyl 4 stroke with 20hp. Generaly speaking the lower the octane the more power it would have. It has no knock sensors so everything is fixed.
 
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I think your motor will be just fine on the E10. Plenty of parts of the US don't have reasonable access to E0 gas at marinas or otherwise, and people seem to be okay boating there.
If you're using a tank of fuel monthly, the fuel will be fresh enough for you, ethanol or not. The only thing you might consider is running a tank of E0 before storing the motor for the winter, if you think of it. But your plan sounds like a good one.
 
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All I can tell you is 90% of my business is cleaning and repairing boat injectors for marinas, E10 is responsible for a lot of injector and composite fuel tank damage, I see it every day.
Unlike car engines boats live on water, the fuel gets saturated with absorbed moisture and at some point it will drop out. The moisture gets into the injectors and corrodes them. I am doing a set today that have rust inside the injector from a metal fuel rail
 

FZ1

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I don't think the e10 will hurt it. Run the gas that runs the smoothest in the engine. You could pick up the tank and shake it periodically to well distribute any condensation.
 
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The key to diverting problems is to use the boat frequently. There are fuel additives that can be used that helps with moisture and corrosion. I use every winter. No problems. STA-BIL 360 Marine. Pour in the prescribed amount, then add the fuel. I doubt you want to shake that fuel tank as previously mentioned.
 
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All I can tell you is 90% of my business is cleaning and repairing boat injectors for marinas, E10 is responsible for a lot of injector and composite fuel tank damage, I see it every day.
Unlike car engines boats live on water, the fuel gets saturated with absorbed moisture and at some point it will drop out. The moisture gets into the injectors and corrodes them. I am doing a set today that have rust inside the injector from a metal fuel rail
Boats that sit do tend to have more issues.
 
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All I can tell you is 90% of my business is cleaning and repairing boat injectors for marinas, E10 is responsible for a lot of injector and composite fuel tank damage, I see it every day.
Unlike car engines boats live on water, the fuel gets saturated with absorbed moisture and at some point it will drop out. The moisture gets into the injectors and corrodes them. I am doing a set today that have rust inside the injector from a metal fuel rail


Flyingdutchman, I suggest you listen to Trav ( his comment is quoted above ) and disregard the comments which claim you won't have a problem with ethanol, because you WILL have problems due to ethanol use, and the only questions are when the problems occur and how much money it costs you to resolve the problems. By the way, Trav appears to be certified as a Master professional mechanic, and for me that would mean his opinion should be weighted more heavily, because he probably knows more than the rest of the commenters in this thread, myself included, and he probably also has a lot more real-world experience.

It would be best in the long run to pay more for the fuel which contains no ethanol. Ethanol is corrosive as well as hygroscopic and the small amount of money you save by using fuel that is less expensive but which contains ethanol will be more than offset by the costs incurred when your engine's fuel system has problems.

Ethanol has less BTU per gallon than pure gasoline, but it's unlikely you will notice the reduced power output if you use fuel which contains 10% ethanol. What you WILL notice is when your engine has trouble starting or running because of corrosion in the fuel system.

Consider the higher cost of the ethanol-free fuel as a form of insurance premium payment. One way or another you're going to pay. Personally I think paying more for ethanol-free fuel is obviously the best choice, but there are always some people who need to learn the hard way ( I don't know if you are such a person, but I doubt you are because you took the time to ask questions about ethanol fuel ).

I own three motorcycles, three cars, and a lawn mower. All these devices get fuel that is ethanol free, after I had to spend close to US $1,000 to repair damage to the fuel injection system on one of my cars. I also had to buy a new carburetor ( this carb was quite inexpensive in comparison to the Bosch fuel injection parts for the car ) for the lawn mower.

I will never again use fuel which contains ethanol in any of my cars, motorcycles, or mowers, unless I am on a long trip and the only available fuel contains ethanol such that the only way I can continue driving to my destination is to use fuel which contains ethanol.

And yes, ethanol is a scam. The big agribusiness companies ( in the US an example of such company would be ADM, Archer Daniels Midland ) have politicians in their pockets so we get ethanol fuel whether it's actually doing the environment any good or not.
 
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If you're using a tank of fuel monthly, the fuel will be fresh enough for you, ethanol or not.

Sorry, but there's seriously flawed logic in that statement.

You have NO way to know how long fuel sat in a large storage tank at a fuel farm before it was pumped into the tanker truck which delivered that fuel to the place where you then pumped the fuel into your boat's tank.

You also do not know whether the fuel in question was pumped into the tanker truck from the bottom of that large storage tank, where more water tends to collect. I used to fuel aircraft professionally, and I am speaking from experience, having drained the sumps of fuel trucks more times than I could count. In the case of aviation fuel ethanol was not a factor, but simple condensation from humid air cooling to the condensation point served to cause significant contamination of fuel, such that draining sumps was done every day, and draining of any given sump was continued until the sample of fuel was free of water.
 
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You will also use more E-10 gas than non ethanol gas. Meaning you will not travel as far with e10.

It’s also VERY true e10 attracts and absorbs moisture with can add to corrosion, a boat sits for long periods of time without fresh new gas constantly replacing the old gas.

You don’t say the age of your boat but if the boat is not made for e10 you can really have issues.

With all the above said if you trailer your boat, it’s not stored near the water and assuming it’s a current boat manufactured with e10 standards you most likely will be just fine using e10 plus a common sense additive for winter storage. (This is what I do)

I do favor non ethanol gas if I can conveniently buy it from a station where I know it’s fresh. Meaning an active station at a reasonable cost. I actually notice more MPG in my Harley King but had been a while since I used it.
 
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pay me now or pay more later IMO. i use E0 in all my carbd equipment, your choice your $$$$. my traded hardly sportster would see 60 mpg on shell premium E0 years ago then when they only had E10 i got at least 5 mpgs less, + as noted boat engines are prolly more prone to issues due to their environment.
 
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Flyingdutchman, I suggest you listen to Trav ( his comment is quoted above ) and disregard the comments which claim you won't have a problem with ethanol, because you WILL have problems due to ethanol use, and the only questions are when the problems occur and how much money it costs you to resolve the problems. By the way, Trav appears to be certified as a Master professional mechanic, and for me that would mean his opinion should be weighted more heavily, because he probably knows more than the rest of the commenters in this thread, myself included, and he probably also has a lot more real-world experience.

It would be best in the long run to pay more for the fuel which contains no ethanol. Ethanol is corrosive as well as hygroscopic and the small amount of money you save by using fuel that is less expensive but which contains ethanol will be more than offset by the costs incurred when your engine's fuel system has problems.

Ethanol has less BTU per gallon than pure gasoline, but it's unlikely you will notice the reduced power output if you use fuel which contains 10% ethanol. What you WILL notice is when your engine has trouble starting or running because of corrosion in the fuel system.

Consider the higher cost of the ethanol-free fuel as a form of insurance premium payment. One way or another you're going to pay. Personally I think paying more for ethanol-free fuel is obviously the best choice, but there are always some people who need to learn the hard way ( I don't know if you are such a person, but I doubt you are because you took the time to ask questions about ethanol fuel ).

I own three motorcycles, three cars, and a lawn mower. All these devices get fuel that is ethanol free, after I had to spend close to US $1,000 to repair damage to the fuel injection system on one of my cars. I also had to buy a new carburetor ( this carb was quite inexpensive in comparison to the Bosch fuel injection parts for the car ) for the lawn mower.

I will never again use fuel which contains ethanol in any of my cars, motorcycles, or mowers, unless I am on a long trip and the only available fuel contains ethanol such that the only way I can continue driving to my destination is to use fuel which contains ethanol.

And yes, ethanol is a scam. The big agribusiness companies ( in the US an example of such company would be ADM, Archer Daniels Midland ) have politicians in their pockets so we get ethanol fuel whether it's actually doing the environment any good or not.
I own a small fuel injector business, that is the reason I see them every day.
 
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I would pay extra for E0 gas for my boat but I would not go crazy trying to find it. My boat will be at a marina with its own fuel pumps. I will probably use what the marina sells.
 

Flyingdutchman

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Thanks for all the replies, the motor is a 20hp 2008 honda outboard and according to the manual it is approved for 10%ethanol. Its a carbed motor so if the ethanol will clog it it will only require manual cleaning which i can do by my self.

However with crossing canals and lakes and sometimes at sea i dont want to risk having any problems so i will probably switch back to E0 then after this tank is empty.
As i said i will consume the 25l tank of fuel atleast every month so the fuel never really gets old. However i now already emptied the tank because there was a small amount of water visable in the bottom. This was however the 2nd time that i filled up the fuel tank. Last year after an entire season on e0 i only had a tiny amount of water compared to what i now already have in 3 weeks.

I dont think it will create any problems however as most said this might come in the long run. It only uses on average a gallon per hour so the increased cost is negligeble.

Its only a visual thing but the e10 fuel is dark yellow by colour and smells also not really like gasoline used to.
The e0 is crystalclear like water and smells delicious. (For a petrol head)
 
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E0 for marine use. You do not want to have engine troubles on the water when the weather is kicking up all because you wanted to save a few dollars on the tank of gas. You could try separating the ethanol from the fuel yourself but then you’re ending up with less fuel so you might as well just pay for the E0.
 
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You have NO way to know how long fuel sat in a large storage tank at a fuel farm before it was pumped into the tanker truck which delivered that fuel to the place where you then pumped the fuel into your boat's tank.

It doesn't sit around very long in this area. Within days of Colonial Pipeline shutting down due to malware in their SCADA network, there were gasoline shortages.
 
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You also do not know whether the fuel in question was pumped into the tanker truck from the bottom of that large storage tank, where more water tends to collect.

If the tank is filled with E10 gasoline, water doesn't collect on the bottom.....until enough water has entered the tank that phase separation has occurred. Then what's on the bottom is a mixture of ethanol and water. And the gasoline on the top is low-octane gas, something below 87 octane (since ethanol serves as an octane booster).

And if all that happens, that fuel tank farm has some serious operational problems.

EDIT: And it appears that fuel tank farms have separate tanks for ethanol and "BOB" (before oxygenate blending) gas.

"Ethanol needs to be mixed into gasoline at the local terminal racks, just before it's delivered. The ethanol and gasoline are splash blended as the tanker truck fills before making the final trip to the gasoline station."

 
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