Ethanol avoidance

Discussion in 'Powerboats' started by tom28571, Sep 27, 2009.

  1. pamarine
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    pamarine Marine Electrician

    only because most aircraft piston engine were certified using leaded gas. You can get supplimental certificate for unleaded mogas (no ethanol), but they are done on an individual basis.

    Aviation gasoline has a lower vapor pressure than Automotive Gasoline (7 vs 14). The Lead is introduced to reduce engine knock, and scavengers to remove the lead residue from the engine. Since aircraft are typically run lean to increase power and efficiency, these two combine to give the best performance at altitude.

    It's just too expensive to change atm. and with non-ethanol gas becoming difficult to find, it may never happen. However, what may being the end of Leaded AvGas is not the led, but the scavenging agent. It is currently made in only a handful of places in the world, but due to environmental concerns, that will eventually end.
     
  2. pamarine
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    pamarine Marine Electrician

    trust me, it still occurs. I'm an Aircraft Mechanic by trade and it is one of the more common ailments in those engines.

    As for the Merc Racing engines:

     
  3. marshmat
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    marshmat Senior Member

    The reported lower mileage when using ethanol, that has been mentioned here, is due simply to the fact that, for equivalent energy content, gasoline weighs about 40 percent less than ethanol and takes up about 40 percent less volume. (Of course, the logical conclusion from this fact is that ethanol at the pump should cost at least 40 percent less than the same volume of gasoline....)

    To those who are having problems with fuel system fouling after their region switched to ethanol blended fuels: Your refineries must be doing something wrong. Or they're cheaping out somehow. There are all sorts of problems that ethanol blended fuel can cause, if it's badly refined or has the wrong additive packages. Properly refined and with the appropriate additives, ethanol blends up to 10% should pose no problem for most engines.

    Here in Ontario, we can get up to 10% ethanol in our 87-octane (R+M/2) gasoline (although, depending on the season and availability, it is sometimes quite a bit less). People regularly add a shot of stabilizer to the stuff, leave it in the tank for eight months of winter, and pump it straight into the outboard in the spring. Problems seem to be rather rare.
     
  4. powerabout
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    powerabout Senior Member

    Marshmat
    I think just the issue that its a solvent and hydroscopic its causing the problems in boats as they have non return fuel systems that are vented to the atmosphere.
    It doesnt seem to like to sit like it does in a garden tool or boat.
    ( being stable while it sits is a fundmental standard of avgas)
    Large production boat bulders in the states will have to use charcoal cannister tank vents from 2010 ( I think) so some probs might go away.

    When I place a small open container of acetone on the ground here in Singapore, after 15 minutes its got a tablespoon of water in the bottom, sucked straight from the air.
    I never saw that happening when I lived in Melboune ( OZ)
     
  5. powerabout
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    powerabout Senior Member

    I wonder if they say that because;
    1) dont test so say dont use ( like a cell phone in a plane)
    2) EPA rules prevent them from saying otherwise.

    I'll drop an email to a mate at BRP and see what they say
    Cheers
     
  6. pamarine
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    pamarine Marine Electrician

    Cell phone in plane is actually well-tested and proven to have some to no effect on navigation equipment, So...FAA says no in commercial airliners (better be safe than sorry, but in these days of digital phones, it's closer to none)

    I think it's both a mechnical and EPA thing.
     
  7. CDK
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    CDK retired engineer

    Works with any volatile liquid in high humidity air. Evaporation lowers the temperature and condensation occurs. Whether or not the solvent is hygroscopic is of no importance.
    I think that the fact that gasoline and water do not mix led to the use of poor materials like paper gaskets and cheap alloys. With the addition of ethanol these weakness becomes manifest.

    I do not understand the negative attitude towards ethanol: it is the major ingredient of a bottle of Jack Daniels.
     
  8. powerabout
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    powerabout Senior Member

    I rememer a few of us putting up a sign in our yacht club Bar( over the drink drive warning one)
    It said
    '
    'Drink dont Drive'
    '
    'Beer cheaper than fuel here'

    That was when fuel hit the roof with the usd150/bbl
    The green lobby in Australia is saying that the ethanol is made from the molasses left behind from the suger production?
    I guess the Queenslanders would be complaining if it up'd the price of that stuff they call Bundy ( Bundaberg Rum)
    ( People think only Australians can eat Vegemite, well only Queenlanders can drunk Bundy)


    Makes we wonder these days what charge ( if any) the good old boys in North Carolina would be charged with if stopped by the police with a car full of bottles of clear liquid?
    Does that make Joe Kennedy an environmentalist rather than a bootlegger?
     
  9. FAST FRED
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    FAST FRED Senior Member

    In a hard working aircraft engine (Takeoff) the exhaust valves are hot enough that spots on the valve and exhaust seat will actually weld themselves together.

    When broken by the next valve movement the welded spot leaves , causing valve seat erosion, and pitted valves.

    LEAD is the lubricant that slows the erosion ,(the parts touch on a film of lead) as well as raising the octane rating of the fuel.

    Removing the ethanol is simple , simply ADD WATER to the fuel in a clear 5-gal jug.

    The water and ethanol will overnight sink to the bottom and the top portion can simply be syphoned off.

    Dump the bottom residue in the gas tank of your local politicos limo.

    FF
     
  10. tom28571
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    tom28571 Senior Member

    Fred,

    I'm no chemist, but what happens to the octane when you do that?
     
  11. powerabout
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    powerabout Senior Member

    it will be lower than what it was as the ethanol is higher octane than pump gas
     
  12. tom28571
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    tom28571 Senior Member

    Yes, and I saw an outboard that had the tops of two pistons blown out and blamed on that from pre-detonation. The factory rep agreed and is replacing the powerhead with only 30 hours on it.
     
  13. marshmat
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    marshmat Senior Member

    Ouch.

    This is one of the rare times I'm glad my boat has a 1994 two-stroke Johnson..... the owner's manual for this thing advises that it is not advisable to use fuel with "less than 67 octane" :D

    On a closely related note, there are some suspicions going around that part of the reason the oil companies like alcohols is that a 10% ethanol blend boosts the octane rating enough that they can use slightly crappier, more cheaply refined stuff for the oil-based part of the fuel....
     
  14. TollyWally
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    TollyWally Senior Member

    I've friends in the oil industry who have worked in refineries. The money is really in moving product through the system smoothly without disruption for good margins. Oil companies don't grow corn, alcohol isn't really their thing but they have to take the heat for it's drawbacks.
     

  15. u4ea32
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    u4ea32 Senior Member

    In California, alcohol has been blended with fuels for a long time -- maybe 2 decades now. It has made a HUGE difference in air quality. I have never noticed any problems with any of my boats, carbed or injected, 2 stroke or 4 stroke, used weekly or quarterly. Absolutely never any problem. No difference with the recent increase in percentage.

    I'm not saying people don't have problems with their boats, but I have never seen a fuel problem.

    Alcohol is SUBSTANTIALLY cheaper per BTU than gasoline: its total cost, including buying the land, irrigation, fabrication, and delivery to the pump, is about $1.10 per the same BTUs as a gallon of gasoline. Its much cheaper than petroleum, so the oil companies use it to (a) meet clean burning fuel standards, and (b) to reduce the cost of their product.

    I only know this because I did an extensive business plan (financial model) for a substantial investor.

    Few people have done this analysis, and those that do, tend to pour a LOT of money into alcohol fuel production.
     
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