age of useable fuel

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Veteran Member
Feb 20, 2012
I am looking for someone to tell the oldest diesel they have in there tank and have used. and if it gets to old can you clean it and how to make it usable.
How much fuel are you speaking of and how old?

If it were in my diesel tank where I know storage conditions, I'd have no problem with 3 - 4 years. Right now I have 2 year old fuel in one tank which works*just fine.

If it were fuel that was suspect and stored for more than 2 years I'd pull a sample and let it sit for a day or two to see what settles out. But, how do you know that it is good stuff for your motor- take it to a testing lab. If in an old woodie and the tanks have gotten rusty and wet, I'd "trash" (give it*away)*the fuel and the tanks and start over.

A few more details would be helpful.

-- Edited by sunchaser on Friday 24th of February 2012 12:35:21 PM
the fuel has been on board in almost full tanks its at least 5 years old maybe older and there over 1000 gallons and fuel price are risinig fast than gold. my idea is filter it going off mix it with something like kerosine and some fuel additive . or add more #1 diesel to it . need some good ideas.
That is a tough one. At almost $5 grand worth.

I don't know.**Polish it and use it?

It may smoke a bit and carbon up some but if you load up the diesel and run at high RPM it may just burn through it.

Waiting to hear the answers myself.

well my son in law works for Cat and he said a nat. cat older model which is what I have Cat 3160 1970 year well be more likly to use it than a turbo unit.
No problem , SUCK (not push) the fuel thru a 2 micron Raycore or your favorite.

Even the paper towel filters will work for this..

Measure the flow back to the tank with a pail, and let the system operate for enough time to suck thru the filters at least 3 times.

No addatives , kero or anything else is required , just get the ashpaltine clumps out , and any water .
ok suck

so do that 3 time and then put it back in a clean tank and you think it well burn fine, and if so have you tried it and if so how old of fuel have you used. and well whats the ff stand for.
I've used diesel that was 7 years old in my old motor home (truck conversion). The filter was a 2 micron racor 900. The engine (turbo charged) was happier once it reached full operating temperature.


Every year I use about 50% of the total capacity of my tanks and add that back in, so some of the fuel in my tanks is from last yr, some from the yr before, some from the yr before that...........
The engines haven't revolted yet. the Racor 500 gets the big chunks (10microns) and the fiters on the engines get the rest (2 microns). When that stops working for me I'll start to worry about the age of my fuel. Until then.........
OF COURSE , cleaning the fuel does nothing for the fuel tank.

That requires a hand job , a wooden spatula works great , hopefully there will be a proper inspection port ,
if the boat has a real fuel tank, instead of a box of fuel.

The motion of the ocean can easily loosen grunge on tank walls , requiring a different style filter.

The best for large contamination is a sock filter.

These are usually glass , so you can see the level of contamination , with a fine woven sock inside.

Every time it gets about half full, shut down , empty the jar , and hopefully with a gravity setup replace the jar , let it fill , and continue.

Usually only bad bumpy weather will require this procedure.

Check with the commercial fish boat supply store.
1,500 gallons of five year fuel was my max, but after polishing it through 30 microns, transferring it at 10 microns and pre-filtering at 2 microns I can't say I noticed any difference in my 3306 turbo.*
"I can't say I noticed any difference in my 3306 turbo. "

Sure you did ,

What about the actual make up of the diesel fuel itself?* After time wouldn't the cetanes* and another ingredients in*the fuel degrade?* Your engine may run but how well?

Or is it just a fuel filtering issue and*diesel has an*indefinite shelf life?*
I was think after the first filter off the boat put in a booster, and something that well kill bacteria or what ever you call it. and then clean the tanks maybe steam them out and then flush them with some fuel and then put it back on with 2 micron and then use it.

and does ff have 3306 turbo's to***** still don't know what ff stands for does anybody else know.
If one believes lubricity additives*have a shelf life and cetane diminishes over time, there is more to using old dirty fuel than merely filtering it and adding mouse milk (attribute to RickB). Me, I'd include in the arsenal of use weapons a diesel testing lab - it is cheap insurance. Testing would throw out the suspicion that a derelict boat's tanks became an old oil, gas, diesel and cooolant dumping ground for others ( yup, it happens). What do your tanks tops look like?

BTW, ff is a transplant to the olesouth.

-- Edited by sunchaser on Sunday 26th of February 2012 08:03:52 AM
o Good thinkin I well pull some out of the tank and send it in I think last time it was like 8 buck to get it tested.

well one f stands for fred.
I think the major concern would be what is using the fuel, like a new engine or an old one..

FWIW: We pulled 110 gallon of red diesel*from a home heating oil tank two weeks ago that had approximately 4 gallons of water at the bottom. Once this is cleaned up, it's off to a happy charter boat.


Oh by the way, the oil*tank was last filled ten years ago....
took that pic when I was at cairrcocaus, it was a great shoot I am sure it still there unless its been scraped by now. and I have no idea why the anchors out.
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