full tank vs. empty tank for storage

[onmedic]

I'm getting my boat winterized and the place i'm storing it at wants batteries out, (for sure, i understand that and will be charging mine every few months at home), but he also wants the fuel tanks empty. He has alot of boats at his place. Looking for some advice on this topic. I know other guys who put in as much as possible so theres less condensation then put in fuel stabilizer. Have also heard the arguement that fuels now a days start to go south right quick even with stabilizer and should start each season with some nice fresh fuel.

 

[Philster]

Re: full tank vs. empty tank for storage

Condensation = myth.

Empty is preferred. If not empty, treat with Stabil or other product of choice.

Either way is fine.

 

[perchin]

Re: full tank vs. empty tank for storage

yep.... empty would be preffered, and also how I store mine.

 

[AllAboard]

Re: full tank vs. empty tank for storage

Condensation = myth.

Do you own a motorcycle? It seems all the bikers say to keep the tank full in the off-season. I do for this very reason. I always wondered myself but was scared to argue with a bunch of bikers LOL

What causes tanks to rust if condensation is a myth?

 

[rwidman]

Re: full tank vs. empty tank for storage

I'm getting my boat winterized and the place i'm storing it at wants batteries out, (for sure, i understand that and will be charging mine every few months at home), but he also wants the fuel tanks empty. He has alot of boats at his place. Looking for some advice on this topic. I know other guys who put in as much as possible so theres less condensation then put in fuel stabilizer. Have also heard the arguement that fuels now a days start to go south right quick even with stabilizer and should start each season with some nice fresh fuel.

If the manager of the storage facility requires the fuel tank to be empty, there's not much point in asking the question unless the answer would cause you to store it somewhere else.

Most experts would recommend that it be stored about 95% full (leave room for expansion) of fuel that had stabilizer added when the fuel was first purchased (you can't 'stabilize" old fuel). Based on my knowledge and experience with condensation, I would agree with these experts.

If the storage area has a constant temperature and low humidity (a cave, for instance), empty would be acceptable.

BTW: Since it's not possible to fully empty a boat's fuel tank, the empty space will be filled with fuel vapor, a potentially explosive situation.

 

[109jb]

Re: full tank vs. empty tank for storage

Condensation = myth.

Then it is a myth that I have experienced first hand.

Empty is preferred.

Preferred by you maybe. I prefer storing with full tanks.

 

[Numlaar]

Re: full tank vs. empty tank for storage

I know where I am at (FL, with very high humidity), that the suggested method is tanks full, with stabilizer... when you consider that fuel tanks are vented to the open air, add in the fact that most now have E10 gas in them, you are getting a water attractant (ethanol) along with high humidity, in a confined space, you WILL get condensation that forms.

If you had a non-vented fuel tank, then the argument can go either way...

Ask to see a water seperator the first run after winter!

 

[Woodnaut]

Re: full tank vs. empty tank for storage

This part of the year is hurricane season around here. Therefore, I keep it full of stabilized gas so I have a good supply for the generator when the lights go out.

 

[oops!]

Re: full tank vs. empty tank for storage

metal tanks......full with stabil.

fuel tanks DO condensate......thats why aircraft have a special tool for checking for condensation in the tanks during pre-flight checks.......if the pilots dont do it.....they die.

in a marine storage situation.....full is allways the way to go unless otherwise specified. (empty is actually a bad policy because the chances of explosion are multliplied with an empty or near empty tank.

cheers
oops

btw...i hate storage questions because that means the season is near the end

 

[Pirate_40]

Re: full tank vs. empty tank for storage

Here's my routine. Some may or may not agree but it's works well for me. I leave them a 1/4 full with stabilizer at layup. Then upon recomissioning I will change the separators add about an 1/8. I Take her for a spin and run it down an 1/8 and I'll drain the separators and change the filters. I'll repeat this process on my next trip with a 1/2 tank and after that, fill er up. Keep in mind that my off season is only six weeks.

 

[Ike-110722]

Re: full tank vs. empty tank for storage

Actually the first poster Philster had it right, Either way is fine, empty or full. It's the in between that gets you in trouble. see http://www.boatus.com/seaworthy/ethanolwinter.asp This is a great article on storing your boat with gas in the tank, or empty.

 

[Triton II]

Re: full tank vs. empty tank for storage

In the military, aircraft are normally hangared with full tanks - to reduce the explosion risk and to minimise condensation. Doesn't matter where in the world, or whether Jet A1/Avtur or Avgas (kero or petrol), or whether it's for overnight hangarage or long term maintenance storage, that's just how it's done (in the air force at least). Most Jet A1/Avtur has an additive called FSII - fuel system icing inhibitor - that lowers the freezing point of the water particles within the fuel (in turn caused by condensation) to about the same temperature as the base fuel, preventing flame-outs due to fuel freezing in the lines at high altitude.

My advice, based on experience is to store full with a stabiliser. Having said that, I often don't follow the advice above, but we boat all year round here so the fuel never gets that old. Just my .02c's worth!

TII

 

[109jb]

Re: full tank vs. empty tank for storage

Actually the first poster Philster had it right, Either way is fine, empty or full. It's the in between that gets you in trouble. see http://www.boatus.com/seaworthy/ethanolwinter.asp This is a great article on storing your boat with gas in the tank, or empty.

If either way is fine then why did the article you linked to have this right in the middle:

DO

* Add Stabilizer
* Top off the tank (to about 95% full)
* Use your boat frequently during the season so that
gasoline doesn?t go stale in the tank

DON?T

* Leave the boat?s tanks partially filled
* Let the boat sit idle for months over the summer.

 

[joehult]

Re: full tank vs. empty tank for storage

Done it three ways over the years, never have had a problem. When i first bought the boat I would top off the tank and use several pints of seafoam. Then I started dumping the remaining fuel at the end of the season, and refilling the tank prior to storage with stabil. But now I just dump the fuel at the end of season, and right before the season starts I dump the remaining fuel and water that gathers during the winter and burn it in an open pit

 

[Triton II]

Re: full tank vs. empty tank for storage

If either way is fine then why did the article you linked to have this right in the middle:

DO

* Add Stabilizer
* Top off the tank (to about 95% full)
* Use your boat frequently during the season so that
gasoline doesn?t go stale in the tank

DON?T

* Leave the boat?s tanks partially filled
* Let the boat sit idle for months over the summer.

To be fair, the article does state that the first choice (largely impractical for most boat owners) is to COMPLETELY empty the tanks. However, because it's not normally possible to do this, then filling to 95% and using a stabiliser is the next preferred choice.

TII

 

[109jb]

Re: full tank vs. empty tank for storage

To be fair, the article does state that the first choice (largely impractical for most boat owners) is to COMPLETELY empty the tanks. However, because it's not normally possible to do this, then filling to 95% and using a stabiliser is the next preferred choice.

TII

The article doesn't say it is "not normally possible", is says "Unfortunately, completely emptying a built-in tank safely is nearly impossible." I would have to agree with it being almost impossible. I had the 25 gallon tank from my Sea Ray completely out of the boat and couldn't get ALL of the fuel out of it and I was rolling it around on its side, upside down, front end vertical, and every which way in-between.

 

[Philster]

Re: full tank vs. empty tank for storage

There is some begging the question going on here.

Those who operate from a premise that a full tank is better at preventing condensation issues come to the table assuming condensation is an issue. Traditionally, the burden of proof is on those making the condensation claims. In other words, you concern yourself with full is better than empty because your premise (which appears groundless) is that condensation is significant in empty tanks.

My premise for empty over full is the ethanol issue, which has better-documented phase-separation issues. Further, many boaters find their boating seasons canceled sometimes, and they are going to be left with old gas... sometimes 80-150 gallons or more in the tank. That's a lot of fuel to sit there and lose octane and be prone to phase separation. Some boaters miss an entire year, or more.

Anecdotal evidence is cute, but a study that is more controlled is much more valid.

Is an empty tank prone to collecting condensation... or isn't it? I posit that it is not, and I cite the following well-respected surveyor.

http://www.google.com/url?sa=t&sour...zqDcDw&usg=AFQjCNEYJBCmXB6vrUaRgUu2qgTJeDQw_A

 

[badkins50]

Re: full tank vs. empty tank for storage

Do you own a motorcycle? It seems all the bikers say to keep the tank full in the off-season. I do for this very reason. I always wondered myself but was scared to argue with a bunch of bikers LOL

What causes tanks to rust if condensation is a myth?

They keep it full so when the weather gives us a break, they can get out without any interference slowing them down .

I leave the gas and treat it for the winter then come next season before I start it up I empty the tank (only 20 gallons anyway) and use it for my lawn toys for the summer.

 

[45Auto]

Re: full tank vs. empty tank for storage

I posit that it is not, and I cite the following well-respected surveyor.

Are you seriously citing Pascoe as a "well-respected" surveyor?? By whom? Some of his stuff is OK, some is atrocious. Thermodynamics is DEFINITELY not his strong suit.

You really doubt tank condensation? Have you ever had a basic thermodynamics class? Can you solve problem 8.171? I'll do it at lunch, don't have time right now and it's been a while since I've had to do any tank calcs - have to dig up a psychrometric chart.

Here's another Marine Surveyor (just as "well-respected") who seems to feel differently than Pascoe:

http://www.limarinesurveyor.com/fuel_systems.htm

Clean fuel is very important to both gasoline and diesel engines but ever more for diesel engines. Water in the fuel will cause the engine to run poorly and may even damage the engine. Boat fuel tanks are subject to condensation due to the set up time that most boats are not used. Changes in temperature and humidity will allow water accumulation inside a boat fuel tank. Fuel water separators are highly recommended for any fuel system. Fuel tanks must be filled to capacity in off seasons this will limit the amount of condensation allowed to form inside.

I deal with fuel tank condensation almost constantly here in New Orleans. Maybe in the northeast it's not a problem, but that doesn't mean it doesn't exist. Do you know what "100% humidity" means? It's pretty much the normal southern weather condition. It means that the dew point is equal to the air temperature. ANY surface cooler than the ambient air temperature will have condensation form on it. We build tanks for the aerospace industry, and there's a reason EVERYTHING built is purged and stored with dry nitrogen inside. Get a little condensation in your boat tank, it gets sucked into the water filter, nobody ever knows. Get a little condensation in your aircraft or spaceship tank, it turns to ice, blocks the fuel flow, and people die. Up to you whether you're smart enough to learn from history or not .....

Pascoe's theories on condensation are as flawed as his theories on electronic ignition and fuel injection. I'm sure GM, Mercury, Yamaha, Honda, Suzuki, Bombardier, Evinrude, etc are dismayed to hear that they've wasted all that development on those electronic ignitions and fuel injection. Maybe you can get all the engine manufacturers of boats, jetskis, motorcycles, snowmobiles, etc, to "respect" him and go back to points and carburetors (along with the non-condensing fuel tanks) since those electronic things are so sensitive to moisture .... my freaking 1972 dirt bike had electronic ignition and it STAYED almost permanantly under water and mud running enduros in Florida!

Why not electronic ignitions and EFI fuel systems? Quite simply because of cost and reliability. Crusader has strictly avoided electronic systems, and rightly so because let's face it, these engines get wet. Whether its leaking decks or hatches, stuffing boxes throwing water or leaking hoses or whatnot, reliability goes out the hatch when sensitive systems are involved. Experience people know that the outstanding virtue is ruggedness and the ability to survive the environment. So, too, ease and cost of servicing. In that regard, you just can't beat the plain old carburetor and standard ignition system.

 

[Philster]

Re: full tank vs. empty tank for storage

45Auto, you have to be the easiest guy to take the bait. The point of my post was that you can't just jump into a thread an operate off a flawed premise. It was instructional in how to make a case, cite a reference, etc.

I live on the ocean, so I am familiar with humidity. I also live in an area that cools/warms, often rapidly.

Your cite is nothing more than more anecdotes (actually, I think it lacks even them). What we could do is find a study that shows just what happens inside a tank... or did that happen already?