Removing water from gas

Had a slight issue last outing and my kicker tank ended up with a lot of water in it. ( rain night before. Vent open and it was strapped to transom )
Now I have 5 gallons of gas in there and quite a bit of water. I want to run it in my lawn mower. I’m thinking I can let it separate in a clear container and pump off the top and leave just a little. Is my lawn mower going to care? I have dry gas that I can add. Or should I really just toss it?

I have poured gas off the top of water and I have sucked the water out from under the gas. Make sure the syphon hose is in the lowest point of the tank if sucking the water out and stop when you start getting all gas. I never had a problem with either. Mower won’t care as long as there isn’t any visible water in it (unlikely anything else would either).

Aircraft frequently drain water out of the bottom of the fuel tanks and the lowest point in the fuel system through quick drains.

I have a bucket I am getting ready to separate. My waste oil drum was left outside with the plugs loose (I thought they were tight). I give my waste oil to a buddy who has a waste oil furnace so I don’t want to give him 10 gallons of water with the oil. The bucket is what I got after I started getting oil out of the drum.

I've done it more than once

no problem. do it all the time

While dyno testing a bunch of diesel engines, we had a fuel cooler go bad and mix about 500 gallons of diesel with water. since we had to get rid of the bad fuel, we filled 9 55 gallon drums with the contaminated diesel and I took it home. I let it sit a month, then using a bottom siphon, extracted the water, ran neighbors tractor and both of Dad's diesel vehicles for almost a year on free diesel.

Syphoning the water off the bottom is less messy . I just tilt the container so one corner is lowest and stick the hose into the corner . Syphon into a clear container so you can see when the water runs out and you start getting fuel . Piece of cake

Mc Tool said:

Syphoning the water off the bottom is less messy . I just tilt the container so one corner is lowest and stick the hose into the corner . Syphon into a clear container so you can see when the water runs out and you start getting fuel . Piece of cake

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this is best answer

If you shake it and let it re-separate you have slightly less ethanol fuel too... depending how much water ended up in the tank.

The first sample I took in a quart jar was nearly 50/50. I pumped a gallon off the bottom and then I got a clear larger container and pumped it off the bottom and let it separate and it didn’t have much at all. Filled my mowers and cans last night.

Pmt133 said:

If you shake it and let it re-separate you have slightly less ethanol fuel too... depending how much water ended up in the tank.

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Alcohol absorbs water. Doing what you suggest puts more water in the fuel. Putting some water and some fuel in a clear container, marking the line where the two meet, shaking the container and letting it settle will lower the water line indicating alcohol in the fuel if there is alcohol present. It is a common test used by pilots to verify no alcohol in their fuel if they buy it somewhere besides an airport.

An easier test is to put a drop of food coloring in the fuel. If the drop stays together and sinks there is no alcohol. If the drop disperses it is being absorbed by the alcohol.

Jeff J said:

Alcohol absorbs water. Doing what you suggest puts more water in the fuel. Putting some water and some fuel in a clear container, marking the line where the two meet, shaking the container and letting it settle will lower the water line indicating alcohol in the fuel if there is alcohol present. It is a common test used by pilots to verify no alcohol in their fuel if they buy it somewhere besides an airport.

An easier test is to put a drop of food coloring in the fuel. If the drop stays together and sinks there is no alcohol. If the drop disperses it is being absorbed by the alcohol.

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When it's in saturation the equilibrium drives the other way. If you leave e10 on a bench in an open jar you will actually see it absorb water and have droplet formation on the surface. If you have enough water in the fuel it can and does drive the other way. We do washes like this all the time in the lab and it chemically is correct.

There are test kits that do exactly this too. E10 will take about a shot of water per gallon before saturation. But the reaction will go the other way. Otherwise those test kits wouldn't be able to show you the ethanol content. It goes both ways.

Add an oz or 2 of two cycle oil. It will color the gasoline and alcohol, but not the water. It will be easier to see when siphoning the water off.

Chris1956 said:

Add an oz or 2 of two cycle oil. It will color the gasoline and alcohol, but not the water. It will be easier to see when siphoning the water off.

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Honestly that’s a great idea. Luckily I was an able to see the water fuel line very easily. It’s kind of mesmerizing watching the water droplets fall through the gasoline