Gunk in the diesel tank

[GeorgeH]

I was topping up the diesel fuel tank on Spartina and didn't check the storage container that had the diesel fuel. When I looked into the container I saw a bunch of crud at the bottom which may have gone into the diesel tank. I can easily pump out the diesel tank but was wondering if I can filter the fuel, clean out the tank and put it back in?

Has anyone done something similar and what would I use to filter the diesel fuel for reuse. Getting rid of 16 gallons would be a problem.

Thanks for any suggestions,

-George

[kerrydeare]

... can filter the fuel, clean out the tank and put it back in? Has anyone done something similar and what would I use to filter the diesel fuel for reuse ...

I have had similar "fun."

You can use a simple siphon tube to empty the tank, but there is little chance you will be able to get the tank completely dry; something will always remain, and the only sure cure is pulling the tank (not a likely option). In any case, just siphon into (say) 5 gallon diesel jugs, and then carefully filter the fuel as you feed it back into the tank. Any simple paper filter device will do the job, and what's left will be picked up by your (multistage, I hope) fuel filters. Of course you will be spending a bit on fuel filter elements.

[Jim Walsh]

I was topping up the diesel fuel tank on Spartina and didn't check the storage container that had the diesel fuel. When I looked into the container I saw a bunch of crud at the bottom which may have gone into the diesel tank. I can easily pump out the diesel tank but was wondering if I can filter the fuel, clean out the tank and put it back in?

Has anyone done something similar and what would I use to filter the diesel fuel for reuse. Getting rid of 16 gallons would be a problem.

Thanks for any suggestions,

-George

Were I in your shoes I would remove the tank if it is twenty years (or more) old so it could be emptied, flushed, and inspected. It can be pressure tested if it appears to be in decent shape and reinstalled. If it looks questionable or fails a pressure test it is the perfect time of the year for a replacement.
My tank lasted twenty three or four years and that is a decent life expectancy for an aluminum fuel tank.
There may be a bright side to your situation. Take advantage of your predicament.

[sgbernd]

It all depends on how much gunk is in there and what it is.

If you see only a little, I'd not worry about it and let the filters handle it, that the the job for which they were created. The gunk will be trapped and come out next time you replace the filters. If the quantity is enough that you think it might clog the filter while underway, you might consider fuel "polishing", which may be hired commercially or you can make a set-up to do it yourself. The idea is to run the fuel in the tank thru an external filter until most of the crud is removed, caught in your external filter. Search the literature for how to make such a system, usually they are a diesel filter with a bunch of spare elements, electric fuel pump, a board on which to mount them, and a inlet and outlet hose of sufficient length to reach into the tank thru the inspection port. If you can gain inspection access to the tank and shine a flashlight into the fuel, it makes it easy to attach the inlet hose of the system to a stiff wire wand and vacuum up the crud you see while you exhaust the cleaned fuel back into the tank.

Regards,
Steve

[Adamkim]

Can you get all of the crud easily like that, Steve?

[sgbernd]

Assuming the junk is just dirt & asphaltenes, and the fuel is clear, the gunk won't adhere to the tank and can easily be sucked out, like cleaning the chunks from the bottom of your water tank every few years. It settles to the bottom so you try to suck most of them out. Since you can't reach the corners, you get what you can, then stir it up, let it settle, and try for some more.

If you have water contamination, bacteria bloom (stringy, gelatinous goo), old cloudy fuel, etc., I'd be more inclined to just suck it all out and replace it. Don't bother to try and filter it. The inspection port on my tank holds the gauge, and is about 2" in diameter so I can't get my hand in. But with a flashlight, I can inspect it and insert a hose zip tied to a wooden dowel or stiff wire. In my case, with a 9 gal tank, the fuel never gets old but for those with larger tanks or infrequent use, old fuel may be an issue. If you are going to replace the fuel, use the same pump you use to suck out the engine oil thru the dip stick.

I don't know which primary filter you have. I have the Fram CSS-1136 which came stock with the boat, which holds more than 1 liter of fuel. It is the same one used for much larger engines (like Caterpillers and Cummins) and ridiculously oversized for my small engine. It can filter a couple thousand gallons of fuel while I give it about 20/year. So a bit of dirt is tolerable.
-Steve

[Tom Keevil]

We use a length of pex plumbing tubing attached to a hand pump to suck out the dregs of our fuel tank. It has the right combination of stiffness and flexibility to work it into the bottom of the tank. The first time we did this, about 15 years ago, a shocking amount of crud came out. Now we do it every Spring, prior to any offshore travel. We pump out about a liter. Generally we get a trivial amount of crud, but it is nice to know - points in your black box.

[Keith]

Hi George,

I had white chunks of something in there (organic I think). I took out the tank tilted it toward the filler tube and sucked everything out with the vacuum pump oil extractor and repeated 2 or 3 times. Don't forget to blow back thru the supply fitting. I actually got a lot of those chunks out of the supply hose in the tank. I did filter and reuse the diesel as it was relatively new. If the diesel is old don't reuse. Surprisingly my al tank is in great shape after 40 years.

Keith