Gas test results are in!

[Has Been]

July 31 I took an extra 6 gal plasti merc gas can & put exatly 2 gal of reg mobil 10 % ethanol gas in it. Crankded down the vent & cap & set it outback next to my shed. Full sun & cool nights till today. Drained it into a 1 gal glass pickle jar. Drained 1st gal & let set for 20 min. Clear as a bell & not 1 drop of water. Took about a tablespoon of water & dropped it in & it fell to bottom & sat there like bb's. Shook tank good & drained second gal & not a drop of water again. 2nd batch only came to about 7/8 way to top of jar. Either pump cheated me or evap. I spilled a little but not that much. Take from this what you want. Thought I would see more water.

[LongLine]

If the vent and cap were cranked down tight, how would water vapor enter the tank?

Tom B.

(LongLine)

[Has Been]

Check back on the original " Gas Question" post.I asked the same question. There was some disscussion about air flow in a sealed tank. that is what prompted me to do the test. What got me is I put exactly 2 gallons in but there was about 1 7/8 or less that came out.

[L&M]

If the vent and cap were cranked down tight, how would water vapor enter the tank?

Tom B.

(LongLine)

viewtopic.php?f=12&t=19184

Interesting test & results H/B. But I have to admit a few of us had a side bet going as to whether your shed was going to survive the explosion or not.

[Has Been]

Who won and where is my cut?

[jimski2]

Is the plastic tank porous to alcohol fumes?

The alcohol in my plastic tank dissolved the plastic on my Cannon Downrigger and beads on my spinners when I left the vents open on my tanks in six weeks. It glued them to the boat's carpet deck.

[goingagain2]

after using the boat all season with never getting above 1/2 tank (86 gal tank)

from 28 apr to 15 oct. i pulled the last 13 gal from the tank.. no water, vent open

all season. the gas i used was all 87 octane from local oswego gas stations, except

the first 40 gal from pa.

john

[mschott]

the rest of your 2 gallons might have been left in the hose after you were done pumping.

[rolmops]

Your lost gas went out of the cap.

When the plastic tanks sit in the sun the fuel inside heats up enough to create extra pressure that causes your tank to swell up like a balloon.Up to a point where the plastic can stretch no more unless it is heated. But the pressure in the tank still increases.Then the safety design of these plastic tanks takes over and allows the over pressure to escape along the side of the cap.

At night when the tank cools of again ,it will go back to its original size ,it may even shrink a bit,but not much.Unless you put it in the freezer there will be no air entering the tank.

That is why there is less fuel ,but no water.

Try the same experiment with the cap just very loose on the can and you will see water in the fuel.

[Has Been]

Was told by someone ( I cant remember who ) That as the tank heated & cooled the air & moisture would move in and out & repeat itself each night , thus moisture buildup no matter how well sealed. . Which is why I did the test . Absolutly NO moisture drops I saw. Dumped fuel with a funnel into the jar. Spilled a little but not that much. Who knows where the 1/8 gal went to or if it was there to begin with.

[rolmops]

Was told by someone ( I cant remember who ) That as the tank heated & cooled the air & moisture would move in and out & repeat itself each night , thus moisture buildup no matter how well sealed. . Which is why I did the test . Absolutly NO moisture drops I saw. Dumped fuel with a funnel into the jar. Spilled a little but not that much. Who knows where the 1/8 gal went to or if it was there to begin with.

Allow me to refresh your memory.

I claim "the heated and cooling" part. The "No matter how well sealed" part was added by Trap Jaw in his contribution to that thread.

[LongLine]

Here's an interesting artile/FAQ's on Ethanol by Mercury Marine. Scoll down & you'll see an interesting picture.

http://www.mercurymarine.com/service-an ... ry=ethanol

Tom B.

(LongLine)

[Big Dave]

although the meter is back in the system, the gas is measured at the nozzle. What is in the hose is taken into account when weight and measures checks the pump. 100 cu. in under and 200 cu in. over in a 100 gallons. Your gallon jug most likley wasn't a calibrated vessel.. The temp. has to be the same when both measurments are made. They don't fill milk jugs to the top to get the gallon, they are down an inch or two. Those hose drainers are stealing gas from the next guy!!!

[Has Been]

That may be true but only if the hose is emptied by the guy before you.Then the hose must be refilled before it hits the nozel,correct?

[Big Dave]

Yes and it will show on the next persons bill. The guy before you stole gas that you will be billed for. That why the stations try to stop people from doing it. Otherwise you would have to have the meter at the nozzle , and that would be hard to handle.

[HPORT]

I would be interested in hearing how the gasoline looked in 10-30 days, ethanol absorbs water readily. If it can mix with water, it can be assumed that some water could have been introduced but not noticable enough to see seperation when you first dumped it out.

Moisture in and out of the tank is common with on-board tanks, they have check valves that allow this inherit action. So just short of plugging the vent, you are going to get a certain amount of air movement as the pressure changes inside the tank. The task of "topping up the tank before storage" would prevent large amounts of moisture in the system. This is true for most any fuel system, not just marine.

John

[Has Been]

Looked clear as glass. Let it set for 10 minutes. Was wondering if I was not seeing things right so I put some water in my hands & droped it in & it sank to the bottom & sat there like BB's.

[ray koziatek]

Phew had some cabbage stew last night ,,NOW THATS BAD GAS RIGHT THERE!!!

IF I could mass produce that great sent we could drop a few sent bombs on the terriost countrys and tell them it would be the normal response for every threat or attack..

WORLD PEACE AT LAST . unless the wind shifts AAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHH!!! GAS,GAS,GAS!!!!!!!!!!!!!!!!!1

[jimski2]

The boating magazines are recommending now that you empty your tanks for storage. Fill them up in the spring with fresh gasoline.

[dewey123]

Romlops is right about where the gas went. Temperature affects the "size" of the gas. You have Gross and Net gallons depending on the temperature they will be different. The pumps dont cheat you out of any gas. They are calibrated frequently so when the state stops by for a surprise they dont get fined for cheating you out of any gas. Ever notice that sticker issued by the state- weghts and measurement dept.? As for using E-10 and putting water in it to see if you have water on the bottom in time....it will never happen. Ethanol (same thing as alcohol.....and DRY GAS) holds water...it will mix right in with the gas particals and burn up and go through the engine.just like dry gas says it does on the bottle. They are the same thing alcohol is ethanol and dry gas alcohol in a little bottle.