50 gallons of fuel

[tomasz]

Hello all,

It's been a long time since I had to ask an question on this forum I do have to say that this forum help me a lot since I joined in June of 2012. My problem is that I'm taking a season off from boating, last time I ran the boat was in October 2014 and next time it will be in water is going to be May of 2016 to that's 19 months. I did put a fuel stabilizer but not sure if that will do for that long. Do you guys have any advice?? I'm concerned that boat will not start or fuel turn into varnish or something like that. If it starts do I run it until all gas is out then replace again water fuel separator, spark plugs and wires??? I would rather try not to drain 50 to be exact 55 gallons of fuel. BTW- Just in case you guys wondering why I filled up my boat at the end of the season - it is because I got that information from this forum to prevent water condensation.

Thank you in advance for your advise.

 

[bruceb58]

I would drain it. I also never fill my boat up at the end of a season.

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

 

[alldodge]

Hello all,

It's been a long time since I had to ask an question on this forum I do have to say that this forum help me a lot since I joined in June of 2012. My problem is that I'm taking a season off from boating, last time I ran the boat was in October 2014 and next time it will be in water is going to be May of 2016 to that's 19 months. I did put a fuel stabilizer but not sure if that will do for that long. Do you guys have any advice?? I'm concerned that boat will not start or fuel turn into varnish or something like that. If it starts do I run it until all gas is out then replace again water fuel separator, spark plugs and wires??? I would rather try not to drain 50 to be exact 55 gallons of fuel. BTW- Just in case you guys wondering why I filled up my boat at the end of the season - it is because I got that information from this forum to prevent water condensation.

Thank you in advance for your advise.

Agree, if it's ethanol gas I would drain it, if it's non-ethanol I might think about not doing it and using stabil. Also get the boat started and disconnect the fuel line at the filter and let it die.

On a side note, if you near me I'll drain it for ya into my boat for free

 

[Alumarine]

I'd take the gas cap off and smell it. If it smells like gas I would just use it.
I don't see a need to replace spark plugs and wires unless they're old and need replacing anyway.
Maybe change the filter before and after running the old fuel? I'm just guessing on that.

 

[UncleWillie]

While I typically drain my tank at the end of the season, There is no reason that the fuel will go bad, Just Because...
If there isn't a source of oxygen and/or water into the fuel, it will just sit there doing nothing.
E-10 does not contain magical 'Pheromones' that attract water from the air like moths to a flame.
There is no air in the tank above the fuel.
The evaporating fuel vapor is heavier than air and sits just above the fuel and displaces any air in the tank in short order.
If you can smell gas fumes coming out the vent, There is no air going in.

If after 2 years, you want to confirm the status of your fuel, pull a sample from the tank into a jar.
Seal and shake the jar vigorously.
If the Gas looks cloudy, you have a water problem.
Normal gas is clear and light yellow in color.
If it is dark amber and will hold a "Head" of foam for more than 5 seconds, the fuel has oxidized and is full of "Gum".


Odds are very high you will not have any problem whatsoever if the fuel system fill caps and vent are working properly.
I have an ongoing experiment with gas in a vented jar. It has been sitting since Nov 2011 and is still looking good.

 

[tomasz]

While I typically drain my tank at the end of the season, There is no reason that the fuel will go bad, Just Because...
If there isn't a source of oxygen and/or water into the fuel, it will just sit there doing nothing.
E-10 does not contain magical 'Pheromones' that attract water from the air like moths to a flame.
There is no air in the tank above the fuel.
The evaporating fuel vapor is heavier than air and sits just above the fuel and displaces any air in the tank in short order.
If you can smell gas fumes coming out the vent, There is no air going in.

If after 2 years, you want to confirm the status of your fuel, pull a sample from the tank into a jar.
Seal and shake the jar vigorously.
If the Gas looks cloudy, you have a water problem.
Normal gas is clear and light yellow in color.
If it is dark amber and will hold a "Head" of foam for more than 5 seconds, the fuel has oxidized and is full of "Gum".


Odds are very high you will not have any problem whatsoever if the fuel system fill caps and vent are working properly.
I have an ongoing experiment with gas in a vented jar. It has been sitting since Nov 2011 and is still looking good.

Wow, that is a great advise. I will surely approach this matter in the way you described it and hopefully the fuel is fine.

Thank so much.

 

[tomasz]

I'd take the gas cap off and smell it. If it smells like gas I would just use it.
I don't see a need to replace spark plugs and wires unless they're old and need replacing anyway.
Maybe change the filter before and after running the old fuel? I'm just guessing on that.

Thank you for your help, I will definitely check out the gas first before I fire my boat up.

 

[tomasz]

Agree, if it's ethanol gas I would drain it, if it's non-ethanol I might think about not doing it and using stabil. Also get the boat started and disconnect the fuel line at the filter and let it die.

On a side note, if you near me I'll drain it for ya into my boat for free

Luckily, my list fill up was at the new gas station not at the marina. The gas station supposedly sells not ethanol gas. Thank you for your help.

 

[tomasz]

I would drain it. I also never fill my boat up at the end of a season.

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

Thank you for your reply. I might give it a try next season and not fill up my boat.

 

[tomasz]

Agree, if it's ethanol gas I would drain it, if it's non-ethanol I might think about not doing it and using stabil. Also get the boat started and disconnect the fuel line at the filter and let it die.

On a side note, if you near me I'll drain it for ya into my boat for free

Thank you for your help.

 

[H20Rat]

If you can smell gas fumes coming out the vent, There is no air going in.

Odds are very high you will not have any problem whatsoever if the fuel system fill caps and vent are working properly.
I have an ongoing experiment with gas in a vented jar. It has been sitting since Nov 2011 and is still looking good.

Great write up, except for that. If you can smell ANYTHING, it means there is air going in. Can't have something coming out of the tank without an equal amount of something going back in, simply physics. Smelling something proves that is happening.

As long as there is an open vent of some sort, you will always have gas vapor escaping, and in return, atmospheric air entering through normal equilibrium processes. Additionally, because of temperature changes, the tank essentially 'breathes'. At a minimum, the tank will suck in air in the evening when the gas cools down, and blow out air in the morning when it warms back up. 50 gallons of gas will change volume by .95 gallons if it changes temperature by 35.2 degrees. That is a substantial amount of air being pumped in and out daily. (not counting the tank itself changing size, which is minimal)

Are your vented jars in a temperature controlled environment? How much temperature swing do they see? Your jar on the right... I wouldn't want that in an engine!

As a related note, the gas in my roto-tiller was completely turned into varnish this spring. Used it last fall. I only burn non-ethanol gas in small engines and boats.

 

[bruceb58]

If you had a 40 gallon tank that was half full and the tank was exposed to a 20 degree F difference every night(unlikely if its really that much). The amount of air entering and exiting the tank would be less than a gallon volume. If that air was 100% humidity EVERYDAY and it ALL condensed(extremely unlikely) you would generate around 1/2 ounce of water in a year's time.

Obviously, not worth worrying about.

 

[UncleWillie]

...Are your vented jars in a temperature controlled environment? How much temperature swing do they see?
Your jar on the right... I wouldn't want that in an engine!...

My Test Facility is an unheated detached garage.
It sees 20 below in the winter, 90+ in the summer, and becomes swampy damp on those spring days when it suddenly warms up.
It is about as real world as you can produce.

It is a Mason jar with a 6 inch length of 1/8 pvc tubing attached to the lid to simulate a vent line.
In 3-1/2 years about 10 % of the fuel has evaporated out the hose. There is no water apparent in the fuel.
This would be expected as others have described, the water vapor in the air can reach equilibrium with the water in the fuel.
100% Saturation is possible but separation due to water vapor is not.

The Jar on the Right was produced via natural processes in under a week.
A Completely Full Jar of Fuel, with no lid whatsoever, was left to do what it would, on a shelf, with normal garage ventilation.
About 10% of the fuel evaporated each day. By day 5 it was noticeably Amber.
By Day 6 it would hold a "Foam Head" for over 3 minutes.
It is notable that no water ever appeared in the gas, despite it being exposed to unlimited ambient air.
And I would declare that fuel as "Bad" without hesitation.

I would like to add that a full fuel tank under a deck, represents a significant thermal mass that is reasonably well insulated from the ambient air temperature swings. Even more so if the boat spends its days on a body of water that changes temperature at rates measured in degrees per week instead of hours.
The air might change 20-30 degrees day to night, But the tank temperature swing will be significantly less.
Warm moist air surrounding the tank may make the sweat on the outside but that does not mean the same thing is happening on the inside.

 

[Bonus Check]

I just drain my tank completely at the end of the season using whatever gas I get out of the boat in my truck. That way at the beginning of the season I put all new fresh fuel in the tank. I have never had water in my empty tank. Sit your empty fuel jugs up in the winter. You know the ones you buy lawnmower gas in. I bet they do not get moisture in them just sitting inside your garage in the winter while empty. Draining the tank when you winterize takes the guess work out of whether the fuel you start the season with is good or not.

 

[UncleWillie]

Great write up, except for that. If you can smell ANYTHING, it means there is air going in. Can't have something coming out of the tank without an equal amount of something going back in, simply physics. Smelling something proves that is happening...

I would argue that vapors can exit a tank without any inflow.
As Butane is a major component of gasoline, and has a boiling point of 30F at ambient pressures; as the Butane and other Components evaporate, they will cause the tank to vent without any air coming into the tank.
A gas vapor smell at the vent, isn't conclusive evidence that air is entering from somewhere else.

 

[H20Rat]

I would argue that vapors can exit a tank without any inflow.
As Butane is a major component of gasoline, and has a boiling point of 30F at ambient pressures; as the Butane and other Components evaporate, they will cause the tank to vent without any air coming into the tank.
A gas vapor smell at the vent, isn't conclusive evidence that air is entering from somewhere else.

How about the other point, of the tank 'breathing' due to daily thermal expansion? It is impossible not to have both inflow and outflow of a vented gasoline tank, if there is fuel in it. The more fuel you have, the worse the problem is.

 

[bruceb58]

The more fuel you have, the worse the problem is.

The amount that the fuel expands/contracts brings in such a tiny amount of outside air that the amount of moisture in that outside air is miniscule even if it condensed 100%, which of course it won't.

 

[UncleWillie]

While a tank may breath you will not smell vapors during the inhale but you will smell them during the exhale.
So, to get petty and anal, if you are smelling fumes nothing is going in. :joyous:

As I keep reading these posts , I start to ask myself, "Does the tank ever actually inhale?" or is it just a given common sense idea that may not be true.
While an empty tank, No Fuel, may be expected to breath, a mostly full tank may not have enough "Lung Power" to reverse the flow. Especially during the summer months.
As the tank and fuel cools the vapor will compress. The 80F(300K) vapor cooling to 60F(289K) will contract 289/300= 4%.
A 25 gallon head space will contract by 1 gallon. If during the same period, 1 gallon of evaporation vapors were to be produced, the net flow would be zero.
That amount to ~1/2oz of gas evaporating from a half full, 50gal tank, over a period of some hours. Quite reasonable!
25 gallons of fuel in a tank below decks may have a difficult time loosing 20 degrees of temperature over the course of a few hours unless the ambient temperature swing was in the 50 deg range. Very unreasonable.
Now during the winter months in the North, with temps well below freezing, the evaporation rates are going to extremely reduced, and the Inhale will be more likely.
To our benefit, when this occurs, the water vapor in the air is also at annual lows. It is Cold, But it is a Dry Cold!
Of course when the air wins, it will float above the vapor of the tank and be the first vapors to be pushed out as soon as expansion took place again.

As stated by Bruce, all this worry about water vapors are...

...Obviously, not worth worrying about.