Possibly water in gas tank due to stupidity

TheRussian

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Jul 10, 2013
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Hello,

When I winterized my boat I accidentally left the gas tank cap open for a couple of weeks while the boat was still outside. During that time we had some snow and rain, and water probably got in. I have no idea how much water could have gotten it, but I’m sure that some did.

Can anyone recommend what do to now? It’s a full tank, so I don’t really want to waste it, and if the only option is to drain the tanks I’m not sure what to do with the contaminated gas.

If I have to drain it, how do I do it? The tank is mounted under the deck, but obviously there are a couple of hatches that allow access... I never opened them yet.

Thanks!
 

Grub54891

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Pump it out into clean 55 gallon barrels. Then flush the tanks with a good dose of fuel,and isopropyl. Wait till it's freezing weather and pump the fuel from the barrels back in,leaving the frozen water in the bottom-I usualy stop short of the ice in the bottom. I've done this on 2 different boats,and never had an issue. To be sure ya have all the water out,I pull the fuel sender,put a rag on a stick and wipe out the remaining leftovers.works for me!
 

tpenfield

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Water and gas don't mix, so that is why alcohol was invented ( among other reasons). If you have ethanol in your fuel, then the water will probably mix right in. Else, get a few cans of 'dry gas' and deal with it that way.

No need to do anything else IMO . . . besides if the tank was/is full, how much water can really get in there :noidea:
 

TheRussian

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The tank is a 20gal tank, and it was full but not completely. I don't think that there is "that" much water in there if any... max a cup or two (I hope)? I put in ethanol free fuel, or at least that's what Shell tells me. So if there is not a lot of water and I can mix it in with the fuel using dry gas... will that actually work and will it still combust? I mean, I don't even have a pump to pump it out with... let alone a 55gal tank.
Thanks
 

UncleWillie

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Oct 18, 2011
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...So if there is not a lot of water and I can mix it in with the fuel using dry gas... will that actually work and will it still combust? ...

YES, it will still combust.
If you can get a siphon line into the the bottom of the tank; Siphon out a few quarts to see if you are getting any water.
A lot of water will be easily visible on the bottom of a jar.
If mostly clear, Shake the jar vigorously. If the gas looks Milky/Opaque, You have a trace of water in it.

If it was E-00 Gas, the water will be on the bottom and it will have NOT stripped the (non-existing) Alcohol out out the fuel.
"Dry Gas" is Methanol or IsoPropyl Alcohol. Adding it to the fuel it will put the Water into solution just like E-10 (Ethanol) gas would have naturally.

Your Fuel mileage may be slightly lower, but not so much that you will notice unless you accurately measure it.
But a 5% loss is much better that the 100% loss if you just dispose of the whole tank.

There is hope, and you are not the first person with this same problem.
This is why the "DryGas"/"Heat" products exist.
 
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HT32BSX115

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The tank is a 20gal tank, and it was full but not completely. I don't think that there is "that" much water in there if any... max a cup or two (I hope)? I put in ethanol free fuel, or at least that's what Shell tells me. So if there is not a lot of water and I can mix it in with the fuel using dry gas... will that actually work and will it still combust? I mean, I don't even have a pump to pump it out with... let alone a 55gal tank.
Thanks

Howdy,

Get yourself some 5 gallon fuel containers.

Go down to the "Good Will" store and buy yourself a good thick felt hat.

Get a large funnel, place the felt hat in the funnel and siphon the gasoline into the hat and funnel into your containers.

The water (and any debris) will be stopped by the felt hat once it's saturated with gasoline.

Leave the boat fuel tank empty and run the gasoline in your car.

Regards,


Rick
 

achris

More fish than mountain goat
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May 19, 2004
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Even a litre won't cause any problems. As water is denser than petrol it will sink to the bottom of the tank. I would take the fuel line off, syphon out a gallon or 2, and reconnect the fuel line. Buy a couple or 3 water separating fuel filters and just change them after an hour of run time. Oh, the gallon or so you syphoned off, let it sit for a day, drain the petrol off the top and ditch the water. You can even return the clean petrol to the boat tank... :D

Chris........
 

redneck joe

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yeah only 20 gallons? use a 5 gallon to siphon, go to gas station on low tank in vehicle, put in, fill up, add Heet. Repeat until gone. When all have been run thru vehicle, use Seafoam (I always double the 'recipie')
 

Bondo

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Even a litre won't cause any problems. As water is denser than petrol it will sink to the bottom of the tank. I would take the fuel line off, syphon out a gallon or 2, and reconnect the fuel line. Buy a couple or 3 water separating fuel filters and just change them after an hour of run time. Oh, the gallon or so you syphoned off, let it sit for a day, drain the petrol off the top and ditch the water. You can even return the clean petrol to the boat tank... :D

Chris........

Ayuh,.... Ya beat me to it,....

It's water, it's sittin' on the bottom of the tank, pump a little bit out, 'n plan on changin' the gas filter again, after yer 1st trip in the spring,...
 

Grub54891

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As bondo and archis said. My methods were done as the boat owners wanted the fuel gone. A couple 80 gallon tanks with 10-15 gallons of water in them from misplaced/leaking gascaps,located right where the flat part of the deck is. Smaller amounts can be dealt with as stated.
 

Bondo

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As bondo and archis said. My methods were done as the boat owners wanted the fuel gone. A couple 80 gallon tanks with 10-15 gallons of water in them from misplaced/leaking gascaps,located right where the flat part of the deck is. Smaller amounts can be dealt with as stated.

Ayuh,..... Don'tcha Love it,....... Free Gas,..... :D ;)

I sometimes wish I drove a gas powered car,...
 

HT32BSX115

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Ayuh,..... Don'tcha Love it,....... Free Gas,..... :D ;)

I sometimes wish I drove a gas powered car,...

Yeah...... I can see a great little business addition here....... "Bills marine gas recycling"!!!! "We'll dispose of your contaminated gas for you!!!" (for a "small" fee of course!!!)

I mean, "CONTAMINATED gas DISPOSAL"!! You don't want anyone thinking that gas is any good!!!!
 
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thumpar

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After doing one of the above make sure you have a fuel water separator.
 

stonyloam

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Ok, let's see about how much water you might be dealing with here. An inch of rain is about 27,000 gal per acre (43,500 sq ft), which is about 0.61 gal (78 oz) per sq ft. Assuming your tank opening is about 2 inches, that is 3.1 sq in/144 sq in per sq ft, or 0.020 sq ft x 78 oz/ sq ft comes out to about 1.7 ounces of water (rain) or about 0.17 ounces of water (snow) per inch go precipitation. That is 2 ounces of water in 2,500 ounces of gas. So you may do as you wish, but if it were me, I would just put on a fresh filter in the spring and not worry about it.
 

HT32BSX115

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The "Felt Hat Trick" is the most unusual filter I've heard of. :eek:

I have filtered many hundreds of gallons of gasoline through felt........Once the felt is saturated with gasoline you'll note that water just "beads up" on the felt and will not pass..........
 

gm280

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After reading some of these interesting ideas, you don't have to go and buy some unique siphoning setup thingy. You have a fuel bulb inline on your fuel line to the engine...right? And so just disconnect that fuel line form the engine and start squeezing it and get fuel flowing and you can sit back and watch as the container fills up. If you use something you can see through, the water should be visible. Otherwise any of the ideas supplied seem plausible to me... I have to admit, I learn something interesting/new every time I read such comments... Oh and for the record, it isn't stupidity, but merely a lesson learned. :D
 

Fishermark

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After reading some of these interesting ideas, you don't have to go and buy some unique siphoning setup thingy. You have a fuel bulb inline on your fuel line to the engine...right? And so just disconnect that fuel line form the engine and start squeezing it and get fuel flowing and you can sit back and watch as the container fills up. If you use something you can see through, the water should be visible. Otherwise any of the ideas supplied seem plausible to me... I have to admit, I learn something interesting/new every time I read such comments... Oh and for the record, it isn't stupidity, but merely a lesson learned. :D

Being an I/O you shouldn't have a primer bulb. It would be a big "no-no." On a related note - simply disconnecting the fuel line and siphoning the gas out shouldn't work either due to the anti-siphon valve.

BUT - I also agree that the easiest and best thing to do is simply change out your fuel water separator cartridge a couple of times. If you don't have a separator installed, now is a good time to install one.
 
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