The Boating Forum - What is this fine white sediment in my fuel?

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02-27-2009, 10:09 AM
Folks I've ben getting a fine white powder-like sediment in my fuel for some time. It is so fine that is passes thru 10 micron Racor and ends up clogging the VST filter in my 250 Yamaha OX66. Any idea what this stuff is? I have now changed to 2 micron Racor and now it collects in the filter bowl but some is till getting thru to the VST filter. I have had the tank professionally drained/cleaned and still the stuff remains. Is the inside of my Al tank corroding? Is this fine white stuff Aluminum oxide?

Any help appreciated.

02-27-2009, 10:12 AM
Yep its caused by ethanol fuel. Just do a search here on Ethanol or VST and you will read all you care to know about the effects of ethanol.

Problem is ethanol is probably here to stay so the best thing you can do is find an additive to ad to the fuel or go thru the expense and put in a plastic fuel tank.

02-27-2009, 11:28 AM
I believe that white sediment in the filter could indicate that water has gotten into the fuel system. You could try testing the fuel for water contamination to rule that out.

Raybo Marine NY
02-27-2009, 11:53 AM
I was told this is from getting moisture in the fuel, then the coating on the tank and the carb starts to fail.

run your motor on a external tank with good fresh fuel and see what happens.

02-27-2009, 11:57 AM
There are two parts of the Ethanol dilema, both result in a white substance. With water contamination the Ethanol causes a "white slime" that later will dry as a powder looking substance and is often found in pre-filters, final filters, VST screens etc. The other source is from the tank itself. Ethanol is an excellent cleaner/solvent and tanks that are several to many years old have already developed a layer of aluminum oxide on the upper sides and tanl top portions of the tank. With just gasoline this was not a big issue. Now add E10 and it will "clean" all that stuff off and then it is picked up into your fuel system. Either way both problems are hard to solve but if it was a water issue at least you have a chance to get the tank cleaned up, free of water. Older tanks need to be replaced.

I went to a local tank mfg (Luther's in Bristol, RI) last weekend to get a new pick-up tube and if you saw the number of tanks being discarded/replaced with new it would shock you. One part of the marine business that is doing very well is fuel tank replacement.

02-27-2009, 11:58 AM
We all know that water and gas don't mix right? Well water and ethanol do and that ethanol will mix with the gas and along with that goes the water.

There is much written all over the internet about the effects of ethanol especially in marine engines and boat tanks.

The biggest problem is Phase Seperation and you will actually get amounts of ethanol up to e-30 with that process either in your own tank or the tank that you purchase fuel from.

So bassically you are all right in your answers.

Raybo Marine NY
02-27-2009, 12:06 PM
I should have been more clear, the powder comes from the motor, not the fuel tank.
Otherwise EVERYONE would have the powder if it was the fuel tanks

02-27-2009, 12:34 PM
"comes from motor"...? Don't know what you mean. I get it in my fuel filters which are nowhere near the motors......

02-27-2009, 01:35 PM
Thanks for all the replys. Sleeper, I think you hit the nail on the head. I had the white slime you describe on all the filters. I did have water in my tank, probably from E-10 gas sitting in my tank for 2-3 months. But I have since had all the gas sucked out, water removed, filtered to 2 microns and then I burned almost 100% out of the tank. I then converted to a 2 micorn Racor and I then refilled the tank with fresh gas and added Startron to the tank. I took the boat out offshore last weekend and there is no more water showing up in the Racor but I still have the white residue in the bowl and it has still started to clog the VST filter. I must have a corroded tank top. Would the E-10 gas along with using some product like Startron eventually get rid of the problem or am I looking at a new tank? The boat is only a 2002 model. I heard newer tanks are coated with something on the inside to prevent corrosion. Man if I'm looking at a new tank, what a hassle.

Tks much

02-27-2009, 01:39 PM
I don't remember the members name but just a week or two ago there was a thread about VST and why the residue ended up there and not in the filters. It was seen as Phase Seperation caused by the vacume in the VST. Just do a search here for VST.

02-27-2009, 03:35 PM
It is also possible that the sediment is from an emulsifying agent added to the fuel. If that's the case, Star tron will help get rid of it over time.

02-27-2009, 07:05 PM
How old are your tanks. I had pretty the same problem in my 1979 Grady White about 12 years ago. I had replacement tanks built. I busted open the old tanks and there was much of this powder from internal corrosion.

02-27-2009, 09:29 PM
run a stabilizer and no more worries

02-28-2009, 04:50 AM
run a stabilizer and no more worries

And keep extra filters on board!:grin:

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