Condensation in fuel tanks over winter...

[trog100]

is this one myth or fact.. ????<br /><br />look at all the condensation that forms on your car widshield every morning and then think of this happening on all the metal surfaces inside your fuel tank.. then feel the desperate need to make sure its as full as possible to cut down both on air volume and exposed surfaces inside the tank.. all sounds logical.. but is it..??<br /><br />there are a couple of good reasons for not filling the tank if u dont have to.. folks seem to think that gas goes bad very quickly and secondly its money better in your pocket than sat dead in your fuel tank.. especially in areas of the world where it would cost 400 US dollars to fill a fifty gallon tank..<br /><br />anyways take a fifty gallon metal tank.. sometime in the fall/autumn put five gallons of gas in there and seal it up.. leave to brew for five months over winter in your backyard then open and inspect gas.. ????<br /><br />useing the windshield analogy the stuff would be pretty watere-logged but based on the simple logic that a certain volume of air can only contain so much water and there is no reason to believe that its all gonna end up in the gas.. there wouldnt be much at all..<br /><br />okay so a gas tank in a boat might not be 100% sealed but if not it could easily be made so.. <br /><br />okay so i cant fault the "better safe than sorry" arguement and praps in todays every-rising price of gas it might make sense to stock up on some in your boat.. but somehow i cant help but feel that the not filling your tank over winter leads to water-logged gas theory is based more on mythology than fact..<br /><br />at the worse a spoonfull of water perhaps.. easily diluted with the addition of twenty gallons of fresh gas in the spring would solve any winterization problems to me..<br /><br />also the gummed up carb theory isnt caused by one float-chamber of gas evaporating over winter its caused by many many float-chambers of gas evaporating due to excess heat in engine compartments everytime the boat is run.. which over time might/does lead to problems..<br /><br />just a thought.. or some thoughts..<br /><br />trog100

 

[tommays]

Re: Condensation in fuel tanks over winter...

Less air less places for condensate to form at least that’s how its worked for me the couple of decades <br /><br />tommays

 

[qaztwo]

Re: Condensation in fuel tanks over winter...

1st Water and gas don't mix. 2nd I would not want to seal a gas tank from the atmosphere. 3rd put a piece of unprotected steel in your car for a few months and see if it starts to rust. Now put it in the bottom of your boat surround by foam wood and glass and let it sit for 10 years. By the way I've sumped fuel out of planes that have only set overnight during a wild temp swing with half to 3/4 full tanks, and gotten more then a spoonfull of water out of them.

 

[Winger Ed.]

Re: Condensation in fuel tanks over winter...

Use a fuel stabilizer and fill the tank. That's the best. As prev. said, 'no air in the tank, no room for condensation to occur'.<br /><br />Or, keep up with your water seperator, and hope for the best.

 

[cmyers_uk]

Re: Condensation in fuel tanks over winter...

I have always filled the tank and never used stabalizer as it seems very hard to come by in the UK. I leave the boat for 5 months and have never had any fuel problems or problems with water in the fuel. Im not sure if there are different additives added to the fuel in the UK though.

 

[trog100]

Re: Condensation in fuel tanks over winter...

the gas going bad quick theory dosnt seem common in the UK as Chris says and i also have never ever come across "fuel stabilizer" praps we do have "better" gas.. who knows.... we should have at the price it costs.. he he<br /><br />Course the other problem i would have is that riverside gas pumps (we have diesel but not gas) dont exist in the UK so gas/petrol has to be "canned" in.. <br /><br />i was worried about all those surfaces inside an empty tank and the full tank less air and surfaces does amke sense.. <br /><br />but the sealed tank or something akin to a sealed tank theory also seems to make sense..<br /><br />to me the air in a boat fuel tank is the "same" air all winter long.. its not continually being changed so any condensation caused by a temperature change would be a one off.. so based on that theory.. assuming the suitable temp change u would get the same amount of water in the fuel in just one night as would get over many nights..<br /><br />course the other factor is that a boat tank sunk in the bottom of a boat as mine is.. covered in wood/glass carpet etc.. isnt subject to constant or rapid temperature changes quite like say an airplane tank would be.. <br /><br />my boat will stay in the water over winter.. England is "damp".. very damp.. at this time of year the entire outside of the boat.. canopy.. windshield.. every thing.. is dripping with water.. so bad i have to put a large towel spread flat on my dash to catch the water that drips off the inside of the windscreen.. this does tend to dry off in the daytime.. but pretty much every night it comes back..<br /><br />my tank is mostly say quarter full<br /><br />now if this kinda thing condensation wise was going on inside my fuel tank (i dread to think) i am sure the engine would never ever start.. water in the fuel would be a major problen all the time.. incidentaly my 89-ish merc isnt fitted with any kind of water/fuel serperator device or filter<br /><br />out of interest in these horrible english conditions my boat had stood.. err.. floated.. unmoved (it probably had the odd engine run and battery charge.. definitely no engine fogging) at its moorings for three whole years before i bought it.. it had about half a tank of gas in it.. wrongly and probably out of ignorance i simple ran the boat and used up the gas.. it ran well enough for me to get it all used up.. i never noticed anything overly wrong with how that engine ran on what should have (theoretically) been unusable gas..<br /><br />my boat had been neglected its a fact.. but it dosnt seem to have done it much harm..<br /><br />now as for the bottom.. well.. he he he.. three inches of fresh water mussels kept the top speed down to about 15 mph and the engine rpm down to 2800 flat out.. the boat in this condition had a wake behind it like the queen mary and the bow was pointing at the sky.. he he he.. impressive in its own kinda way but not very efficient.. whoops..<br /><br />it didnt tale long to use the half tank of gas in this condition by the way.. he he he<br /><br />with a clean (ablative antifoul paint) bottom the boat tops out about 40 mph and 4800 rpm<br /><br />living and learning.. trog100

 

[tommays]

Re: Condensation in fuel tanks over winter...

trog<br />i dont how you guys get away with out the water sepator in the US thats like asking to get stranded<br /><br />but then we now get a 10% methanol blend that sucks up water like a spounge in fact in the US there are about 19 regional blends of fuel to control emissions as well as many places that just get 100% gas <br /><br />tommays

 

[Winger Ed.]

Re: Condensation in fuel tanks over winter...

Originally posted by trog100:<br /> the air in a boat fuel tank is the "same" air all winter long

That only works if the tank is sealed.<br /><br />If its vented-- as most are, there is air circulation.<br /><br />During a warm day, the air inside expands and vents out.<br /><br />When the air cools at night; cool, moist air gets sucked back in.<br /><br />If you have a high humidity condition, like when the 'dew' falls on your car and everything else outside, its condensation from the moist air cooling.<br /><br />When that moist air gets sucked back into the tank every night, and then it warms the next day, the water sweats out and condenses on the airspace inside the tank walls as 'yesterday's air vents back out.<br /><br />Then, 'last night's moisture' from the air that was sucked in, runs to the bottom of the tank as liquid water. Next day, the cycle repeats.<br /><br />The bigger the air space, the more and more condensation you'll have building up in the tank. <br /><br />About the most critical application of a gasoline engine is in an airplane. The condensate forming like it does is why they are supposed to be stored with the fuel tanks topped off as full as you can get them.

 

[trog100]

Re: Condensation in fuel tanks over winter...

probably wrong to "think" about these things but my mind wanders to garage and marina fuel tanks and how they cope with this condensation problem.. i am sure they are not full all the time.. my marina has just installed a new diesel tank.. it sits above ground subject to about as much temperatures change as u can get.. ???<br /><br />a few years ago (about 25.. he he) i had an old car i used to run.. it didnt do a lot of mileage thow it was in daily use..<br /><br />in the winter it developed a strange problem.. it would fire up perfectly but after about a few hundred yards of "driving off" it came to a stop.. all it would do was idle.. any attempt at opening the throttle stalled it.. thow it still idled perfectly.. after about ten minutes the problem disappeared and the car drove perfectly..<br /><br />anyways mucho headscatching and a bit of swearing went into trying to find the answer to this intermittant problem.. it only happened "sometimes"..<br /><br />i found the answer by accident really.. having pulled the aircleaner off and replaced it (as u should.. he he) many times.. one day i did as u shouldnt and left the bugger off.. the next time it happened it was obvious what was happening..<br /><br />looking down the down-draft carb (after this couple of minutes drive off period) revealed a lump of ice about as big as a sugar-lump sat nicely on top of the main jet.. no ice anywhere else only on top of the main jet tube.. as i said earler even with this lump of ice the car idled away perfectly.. course after about ten minutes the lump of ice melted and off went the car for the rest of the (engine warmed up) drive perfectly..<br /><br />with the aircleaner on of course this lump of ice couldnt be seen and by the time it was taken of the bloody lump of ice had melted which was why it took me so long to find the answer.. and of course it only happened during actual freezing temps..<br /><br />this gets a bit sillier but a long time ealier i had lost the fuel cap of this car and simply bunged a rag in the hole to bung it up.. the car had a nice fuel flap which covered the rag so being as it didnt look unsightly it kinda got left.. he he <br /><br />sillier still.. the filler cap on this particular car was on the top of the rear wing not at the side as they mostly are.. underneath this nice looking flap was a kinda well which collected water.. my rag-type fuel cap was actling like a wick.. soaking up this water in the well and very neatly dripping it into the fuel tank.. removing the rag got rid of the problem.. i never did get around to replacing the proprietory fuel cap..<br /><br />only a couple of gallons of fuel in the tank.. a steady drip drip of water from my "wick".. governed of course by how often it rained and that well filled up.. that fuel had one hell of a water content.. but apart from the problem of actual freezing of this "water" at the point it met the icy blast of cold air as it came out of the main jet tube during actuall below freezing point temperatures and only then during the "cold engine" drive off period.. it didnt seem to affect the way that engine ran in the slightest.. ???<br /><br />basically my experience over a lifetime lead me to believe that fuel can contain a high water content.. that it probably does far more often than we believe.. that except in real freezing conditions it doesnt cause the problems that we think it does..<br /><br />that a nice see-thru water trap in the fuel tells u what is happening but u dont really need one and that fancy filter type arrangements might well do more harm than good.. especially if they bung up and refuse to pass anything due to too much water being trapped in em..<br /><br />i am also inclined to think that even thow we all know that fuel and water dont mix that somehow it does (praps only in droplet form) it dosnt just lay in pure water form in the bottom of the tank.. else our engines would never start at all.. especially that one i had twenty five years ago..<br /><br />who knows.. its better to be safe than sorry and to have an airplane engine fail due to fuel freezing might well be fatal.. especially if the bugger cuts-out just after the wheels have left the ground.. whoops..<br /><br />trog100

 

[Catchem]

Re: Condensation in fuel tanks over winter...

Ethanol enhanced gasoline "will separate"after a couple of months.Hence the need for stabilizer in your gas if you are storing it for any length of time over 2 months,be it car ,bike or boat,etc.

 

[Winger Ed.]

Re: Condensation in fuel tanks over winter...

Originally posted by trog100:<br /> garage and marina fuel tanks and how they cope with this condensation problem

The pick-up for most gasoline tanks is a 'skimmer' that floats on top of the fuel level.<br />Horror stories abound of fuel being put in a car when the storage tank was near empty and the skimmer sucked up the water that accumulates in the tank and overwhelms the fuel seperator/filter on the car. <br /><br />On Diesel storage tanks, there is a very elaborate filtration and water seperation system that the fuel goes through before its delivered. If a few drops of water make it into a diesel engine through the fuel injectors, it won't just run rough for a minute--- it will be destroyed.<br /><br />Since your car did so well 25 years ago, your boat will probably be fine. I wouldn't worry about it.

 

[trog100]

Re: Condensation in fuel tanks over winter...

to be honest i dont overly worry about it..<br /><br />i also remember twenty years back having to light fires under truck diesel tanks during long periods of freezing weather before the buggers would start..<br /><br />did we really do things like that.. kinda makes me wonder how we all survived.. he he he..<br /><br />incidentally i am pretty sure we dont have this ethanal in our gas like it appears u do in the US ours does seem to keep.. course we could just be living in blissfull ignorance of having it which also might be another reason why no one seems to sell fuel stabilizer.. dunno<br /><br />anyways my boat will sit in the water over the english not overly cold but very damp winter.. i will give a little run every one or two weeks just to kid myself that it still runs.. i have an oil filled electric radiator thingy in the boat i set to come on overnight if the forcast says below freezing temps for more than one night.. it will have praps a quarter tank of gas most of the time.. i will let u know how it fares.. <br /><br />trog

 

[Richard Petersen]

Re: Condensation in fuel tanks over winter...

Do we really have to worry about our boat engine so much? We sure as hell don't worry about the same engine and gas brands in a car left alone for months in the winter. They DO NOT have sealed tanks. They are made of a rust-proof metal just like a marine tank. Get over this. The stuff is sold to make money. 1920 to 1990 NO ONE ever needed "stabilizer". The only thing it stabilizes is, some ones income. I have never changed the antifreeze in any car I have owned since 1970. Not 1 had a coolant problem. Some had 125,000+. Change my foot.Additives mean the big industries make unsafe products. Crap- from the fear PR people hustling SNAKE OIL.

 

[Richard Petersen]

Re: Condensation in fuel tanks over winter...

Trog 100 I think is absolutly right on his thought of fuel bowl evaporation on hot shut downs of carbed engines. After a 3 mile run at 4800 rpm and a very quick slow down in gear, in summer brings on a rough idle in gear for about 2 minutes. Goose it and it runs fine. Old fashioned case of " percolation of fuel " it gets to hot with out a fuel line cooler just before the carb.

 

[Richard Petersen]

Re: Condensation in fuel tanks over winter...

This a procedure that works great on O/B engines that can't start, lawn mowers, chain saws, generators and just about any engine that sat long enough to dry out the fuel bowl. More than 1 year old ? FIRST - do not try to start it!!!! drain all the old fuel out. It has probably evaporated all the high OCTANE vapors out. That is what really starts the engine. Put in a 1/4 tankfull of HI TEST. Open the fuel shut off valve. Let the fuel flow into the carb. Let it sit for at least 1 hour. Reason? fresh gas dissolves the old dried film of varnish in all those tiny fuel holes. Choke the engine normally, it will start as easily as the last time you started it. If not, A gasket has split or the float is now soaking up fuel.

 

[tommays]

Re: Condensation in fuel tanks over winter...

i want some of that 30 year antifreeze and i really want to buy a marine fuel tank thats made out of never rust/corrode metal it will save boat owners all these problems with cuting up the floors to change that leaking fuel tank<br /><br />and do you also have some never rot wood<br /><br />tommays

 

[Richard Petersen]

Re: Condensation in fuel tanks over winter...

I guess you will have to join me as a beleiver and happy owner of only Honda and Nissan cars. I have never had to replace anything except - air filter, oil, oil filter, tires, air in tires, windshield washer fluid, wiper blades and add gasoline. they always pass emissions in N J. Period. I love muscle iron, but I will not support poor quality. Oh, I faithfully change the oil every 10 to 12,000 miles. The engines crank case only uses filtered air. How does dirt get in the oil? They laugh all the way to the bank at 3 to 6,000 mile oil change and filter people. I am 67 and have grown up with con artists in almost every line of bussines.

 

[Richard Petersen]

Re: Condensation in fuel tanks over winter...

Do you really beleive the boat manufactuers specify a tank metal that will rust? I think the USCG requires a tank metal that will not rust. After 5 years a tank is on it's own.