Gas additives?

[Keith7481]

I'm in the process of buying a used boat, 1998 Four Winns 238 Vista, 5.0 OMC/Volvo SXDP. The current owner tells me he uses a fuel additive because of concerns about how ethanol could affect the engine, but he wasn't very specific about what problems might occur. Anyone have any thoughts on this issue??

 

[Fishermark]

Re: Gas additives?

I suspect that most additives at best do no good - and at worse cause many problems.

Even Stabil can cause problems as it emulsifies the gas and water and keeps the water from separating out of the mix. A little bit of water - not a problem. A LOT of water - big problem.

I avoid additives altogether.

 

[havasuboatman]

Re: Gas additives?

I agree with Fishermark, Use fuel stabilizer for a boat that is going to be stored. But that is all. when you fuel use quality fuels

 

[Bondo]

Re: Gas additives?

The current owner tells me he uses a fuel additive because of concerns about how ethanol could affect the engine, but he wasn't very specific about what problems might occur.

Ayuh,.... My guess is, he isn't to specific, 'cause he don't have a Clue....

The Ethanol gas seems to be tough on some fuel Tanks,+ plumbing,...
But,..
The motors don't seem to care at All...

 

[Keith7481]

Re: Gas additives?

That was my thought as well. I have an older motor (1986,3.0) that works just fine with gas with 10% ethanol, I was just concerned that the newer motor could be more fussy. Thanks for the replies.
Keith

 

[bruceb58]

Re: Gas additives?

Its only a problem when you get enough water in your tank so that you get an emulsion because of phase separation. He was probably using a gas drier. Not a problem using an additive for that.

 

[HT32BSX115]

Re: Gas additives?

Howdy,



It's a common problem that some think ethanol is responsible for problems by mixing with condensed water and then phase separating.

10% ethanol doesn't seem to hurt anything......(However, it IS a problem in some fiberglass tanks because the ethanol will soften some resins that boat makers used to use.)


Having operated, worked on and flown little airplanes since the 70's, a lot of us used to worry about moisture condensing in the fuel tanks if the tanks were left "not full".

There's similar worries with marine fuel tanks.


My experience is, I have NEVER found water in an aircraft fuel tank regardless of fuel level.

I also thought condensation would be a problem in boat fuel tanks if left at any level other than full. I never have experienced water in a boat tank either......and I have always thought the "old wives tail" about it was suspect until I read the following article by a Marine Surveyor.

http://www.yachtsurvey.com/myth_of_condensation_in_fuel_tanks.htm


I also used to think that leaving gasoline in a tank for 6mo or more needed Stabil, Seafoam, or other snake oil in there with it.

Now I don't worry about it.

Now I just put the boat away with 1/4-1/2 tank. I fill it up and change the fuel filter before I use it next season.

In most cases it's only going to sit for 6-8 months anyway. (SEP-MAR etc)


Cheers,


Rick

 

[Silvertip]

Re: Gas additives?

Watch for my E10 fuel test tomorrow (provided I remember to take the pictures) and measurements. That ought to keep the Forums humming for the rest of the winter. 28 below zero here a couple days ago. E-85 at $2.19/gal vs $2.74/gal for regular. My Impala loves corn squeezins and so does my wallet!

 

[Don S]

Re: Gas additives?

I'm going to move this thread over to Boat Topics and Questions, since it's not just a question with IO's, but also outboards, and in Boat topics, the outboard guys will have a chance to see this too.

 

[HT32BSX115]

Re: Gas additives?

Watch for my E10 fuel test tomorrow (provided I remember to take the pictures) and measurements. That ought to keep the Forums humming for the rest of the winter. 28 below zero here a couple days ago. E-85 at $2.19/gal vs $2.74/gal for regular. My Impala loves corn squeezins and so does my wallet!

Your GM (Govt Motors) Impala is a "Flex-Fuel" car?


What sort of mileage does it get on E-85?

 

[QC]

Re: Gas additives?

E-85 at $2.19/gal vs $2.74/gal for regular. My Impala loves corn squeezins and so does my wallet!

Your wallet has been hosed . . . A gallon of E85 only contains approximately 82,393 BTUs, a gallon of gasoline contains approximately 116,090 BTUs. Ultimately you pay for BTUs, not volume You'd need to pay $1.94 per gallon to break even. These are Low Heat Value (LHV) figures. Any responses need to consider/reflect that as well.

 

[bruceb58]

Re: Gas additives?

Watch for my E10 fuel test tomorrow (provided I remember to take the pictures) and measurements. That ought to keep the Forums humming for the rest of the winter. 28 below zero here a couple days ago. E-85 at $2.19/gal vs $2.74/gal for regular. My Impala loves corn squeezins and so does my wallet!

The regular gasoline is a better buy if you are going by BTU content. Many people will say "Well I get this MPG so its cheaper". Mainly wishful thinking.



E10 has 0.1 * 76 + 0.9 * 115.5 = 111.55K BTU/gallon
E85 has 0.85 * 76 + 0.15 * 115.5 = 81.93BTU/gallon

E10 $2.74/111.55= $0.0246/KBTU or $2.46 / 100,000 BTU
E85 $2.19/81.93= $0.0267/KBTU 0r $2.67 / 100,00 BTU

E10 is cheaper and you don't have to fill your tank up as often.

Note:Edited my original numbers using LHV

 

[SNye45]

Re: Gas additives?

I have a main engine (115hp EFI) and a 9.9 kicker on my boat.

I have had all kinds of problems with fuel with my 9.9 but none with the main. A local dealer told me that since the EFI "atomizes" the fuel before it "ignites" it can cope with the 10% ethanol in normal gas, but since the 9.9 is carbureted "fuel is drawn in" the carbs get clogged up very easily. After an expensive cleaning bill, I now run the 9.9 fully open and have bitten the bullet and now buy only un-ethanol gas.

Just my 2 cents worth

 

[bruceb58]

Re: Gas additives?

You can look here to see what the mileage numbers are. Flex Fuel Vehicles are included.

http://www.fueleconomy.gov/feg/download.shtml

For a 2007 Impala

Impala FFV
16/23 ...E85
21/31 ...Gas

Looks like they see a 75% delta

So if gas is $2.74, the break even point is $2.06

 

[coolguy147]

Re: Gas additives?

i used stabil on my little gas tanks. 2 gallons and 1 gallon because i usually dont use them up all the way. weed eater lawn mower maybe atv every once in a while.

i prefer seafoam. i believe its the best. except i mainly use stabil cause its cheaper lol

 

[QC]

Re: Gas additives?

Yeah, Bruce, we were posting at the same time obviously . . . Energy content is somewhat variable by region, season and local gasoline blends. Hence the differences, but the point is the same, E85 is not equivalent to gasoline, so neither are economic comparisons that do not equalize the energy.

 

[HT32BSX115]

Re: Gas additives?

i prefer seafoam. i believe its the best. except i mainly use stabil cause its cheaper lol

I prefer neither. Which is even cheaper.

I now run the 9.9 fully open and have bitten the bullet and now buy only un-ethanol gas.

Not sure what you mean by "fully open"

E10 doesn't really cause any problems in small carbureted engines.

Even if you think you're getting "un-ethanol" gas, you may be mistaken..... A lot of stations are selling E10 now and even they don't know they're selling it.

There is NO gasoline in this country that is oxygenated with MTBE or ETBE anymore. It was banned several years ago.

If you live in an area that requires oxygenated gasoline, you'll be running E-10 (which can contain 5-10% ethanol ..... EPA currently limits it to 10% (except in E85) but that may change if they have their way...)


I have run E10 in everything I own from lawnmowers to tractors, cars and boats and I cannot tell any difference. We don't get non-oxygenated gasoline here in Western Wa any more.

If you want to be absolutely sure that you're NOT using E-10, you'll need to test your fuel using the procedure in the following link.

Otherwise you may be surprised to know that the fuel you thought was alcohol free, isn't!


http://www.eaa.org/autofuel/faqs/alcohol_testing.asp



Cheers,


Rick

 

[H20Rat]

Re: Gas additives?

I run e40-e50 in my turbocharged car, and it loves it! I have specifically tuned it for that mix of fuel, I was able to raise timing quite a bit, as well as go to around 20 psi of boost. Ethanol has a much higher effective octane rating, as well as burning cooler. (I saw a dip in EGT's immediately) After I got all the bugs out of the tune, I ended up dropping about 1 to 2 mpg, but gained a SUBSTANTIAL amount of torque and hp in the process. (The mpg drop might be caused more by my right foot than anything else)

 

[kaferhaus]

Re: Gas additives?

My experience is, I have NEVER found water in an aircraft fuel tank regardless of fuel level.

Well then you're the only pilot I know that's never found water in fuel tank. I've drawn off as much as 4-5 ounces at a time during pre-flight inspections and that is from 20Gal tanks.

Perhaps you live in a very arid evironment, here in the deep south with high humidity and often little temp separation between the dew point it's VERY common to find water in aircraft fuel tanks.

Otherwise there'd be no point in that little clear plastic tube that every aircraft has for detecting water in the fuel or the drain cocks under every wing....

I also did a lot of flying in the SF bay area back in the early 80s... finding a few ounces of water in the tanks was not uncommon there either.

 

[sickwilly]

Re: Gas additives?

Please edit again -- it does not add up. You indicate that Ethanol has 84.6 BTU -- therefore a mix that is 85% Ethanol and 15% gasoline (with a BTU value of 125K) could not have a lower BTU value than the Ethanol value alone -- which your formula says = 81.9 BTU.

The regular gasoline is a better buy if you are going by BTU content. Many people will say "Well I get this MPG so its cheaper". Mainly wishful thinking.

Regular gasoline 125K BTU/gallon
Ethanol 84.6K BTU/gallon

E10 has 0.1 * 76 + 0.9 * 115.5 = 111.55K BTU/gallon
E85 has 0.85 * 76 + 0.15 * 115.5 = 81.93BTU/gallon

E10 $2.74/111.55= $0.0246/KBTU or $2.46 / 100,000 BTU
E85 $2.19/81.93= $0.0267/KBTU 0r $2.67 / 100,00 BTU

E10 is cheaper and you don't have to fill your tank up as often.

Note:Edited my original numbers using LHV