Water in Fuel

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I suspect a small amount of water entered the fuel tank as the cap on boat was not replaced after fueling and the boat had begun to be washed down. Engine is Yamaha F150 with external canister water seperating filter. Boat is a 2004 model 208. Boat is in water. Should I add any type of fuel additive? Tank has 30-40 gallons of fuel in it now. Have heard that some fuel additives may be bad for motor being run on auto gas staion fuel which contains ethanol? Thanks
 

Doc Stressor

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E10 gas will hold up to about 0.5% water. So you may well be OK.

There are a few additives that will increase the amount of water that the fuel can hold in suspension. However, the effect is small. It's never more than the volume of fuel additive that you put in the tank. Adding fresh dry E10 is actually more effective since it will hold more water.

If you do get phase separation, which will be visible in your fuel/water separator, you are screwed. There is no product that can really reverse the problem. You'll have to pump the tank and either discard the fuel or have it polished (filtered, water removed, octane level restored).
 

SmokyMtnGrady

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I am not a water in the fuel expert. Do you really know how much water got into the tank? A few drops or a few gallons? If it is a few gallons and it was my boat I would get rid of the gas. Take somewhere and empty the tank out completely. Some might suggest having the gas conditioned where upon folks run the fuel through a series of water fuel seperators and back into the tank. I am not familiar with this and can not offer an opinion one way or another on its effectiveness. Others may be able to offer insight on this.

I live in an area where I can not readily get ethanol free fuel, hence gas station fuel. At every fill up I add Yamaha Ring Free and Stabil. I would think Ring Free is a must using gas station gas more so than ethanol free gas.
 

alfa1023

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Couple of options in my opinion based on past experience.

When I got my 330 Express. found out the hard way (motors stopped) that I had excess amounts of water in fuel tanks. Had a guy come to the house (boat is on a lift in backyard) and "polished" the fuel. Basically a process through agitation and big arse fuel / water separators that takes the water out of the gas. Took almost 5 gals of water out of my gas tanks.

Easier option would be to run the boat for a little while (maybe 30 minutes) and then stop and pull your fuel / water separators and drain them to see how much water is in them. In the above case, mine were 100% full of water. Be sure to have several spares on hand as you will not want to reuse the separator once it has had a bunch of water in it.

Good luck and let us know how you make out.
 

Doc Stressor

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The only problem with that is if you do find water in the separator bowl bowl when you're using ethanol containing fuel is you already have phase separation. While the engine will run until the water/ethanol layer saturates the filter element, the octane level of the fuel phase will only be 84-85. Since your F150 requires 87 octane, that can cause detonation and engine damage. That's why they boost the octane back up after they polish ethanol containing fuel. Most of the ethanol will be removed with the water and that lowers the octane. If your engine has a knock sensor, there shouldn't be any damage. But if some of the water emulsion gets into your fuel system, it will need to be completely cleaned out. That means new internal filters, including the VST filter element, and often the injectors.

So the best way to proceed is with common sense. Understand that 10 gallons of E10 will hold about 1-1/4 oz of water. If only an ounce or two got into the tank, just add some fresh E10 and keep checking your fuel separator bowl. If you see any cloudiness indicting an emulsion, stop the engine and get the tank pumped.

There is a product called K100 that is mostly 2-butoxyethanol. This is a type of alcohol that will increase the ability of E10 fuel to hold water. But you need to add a lot of it if you want to dry out a wet tank. Like over 8 oz per 10 gallons. I'm familiar with the chemistry and it should be able to emulsify water in the fuel on a volume to volume basis (1 oz should hold up to 1 oz of water). But I haven't used it myself, so I can't really recommend it. Pumping emulsified water at high pressure can damage fuel injectors.
 

seasick

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I have left my fuel cap off on my 208 twice. One time it rained like heck for 3 days before I noticed the cap.
Bottom line? Not any water in the tank. I actually pulled the sender and pumped out the bottom of the tank to be safe. The second time I just put the cap on and went about my boating. The design of the cap and its placement is good and flowing water doesn't run over it, but rather around it.
I suspect you will be fine..
If you start to have some issues, then you would investigate further.