How long will diesel stay good in tank.

[sunsetacres1318]

I have a 50 Hatteras Sportdeck. Located in Florida. We bought it to Florida two years ago. When we arrived we filled each tank with diesel with some fuel additive. Since the fill up, we have taken several short trips but still have a half tank showing in each tank. How long will this diesel stay good? Would it be a good idea to refill tanks and add some more additive? The engines are sounding and running great. Any comments or suggestions would be appreciated. Thanks!

 

[Glory]

A long time.

 

[johnjen50]

Really long. If you have an onboard fuel polisher I would run that. That will bring the color back to a deep cherry red. The issue may be when you go out in bumpy conditions it may stir up any crap and clog your filters. Just be sure to know how to change them and you should be good.

 

[JD5652]

I have three year old fuel in my 58 LRC and it works just fine....

 

[Briankinley2004]

Fill up both tanks with fresh fuel and run it. You can have it polished if you like. If you have Detroits they will run on a lot worse as long as it is filtered

 

[SKYCHENEY]

We've burned diesel in trucks that was 20+ years old before with no problem.

 

[SEVEN]

I use 3/4’s of my fuel each year and fill it up in November for the winter. 11 years zero issues.

 

[Eddieclemons]

I can't seem to get my fuel to last near that long, it's constantly evaporating.

 

[Len R]

I bought a new to me boat this year. She had 3/4's in 2 tanks. The previous owner passed away, the boat was on the hard for 4 years. Ran it through with no problem. Water in the tank is your enemy, it will contribute to algee growth. Treatment is cheaper than repairs. As Eddie said evaporation is the issue.

 

[matthewgraham]

there will be no problems you can add fuel or use up the rest

 

[rsmith]

If you’ve ever seen any end of the world movies they usually have scenes of NORAD the underground command center in Colorado. It is a real place. It’s deep under Cheyenne mountain in Colorado Springs. In the 50’s when it was built they Pumped 10’s of million gallons of diesel into limestone caverns incase of nuclear war. Up until it was closed in the 2010’s they routinely ran the giant diesel generators on the 60yo fuel.
If you run the boat and don’t fill the fuel tanks each time especially in Florida you will have water condensation in the fuel tank. You may know that there are fuel coolers on most diesel engines. These cool the return fuel going back to the tank. The fuel is still pretty warm and after some running your tanks will feel warm to the touch. As the fuel is used it’s replaced by warm moist air being pulled through the vents. The fact that the vents are on the side of the hull picking up they not only pick up saturated air but mist and spray. As the tanks cool the water comes out as condensation and drips off the inside top of the tank and down into the fuel. This is where the algae forms. The only way to minimize this is to fill the tanks after every use and exhaust all the moisture laden air before it condensates. Otherwise treat the fuel with a biocide and keep draining the racors.

 

[jim rosenthal]

Treat the fuel with Biobor or Stanadyne and it will last ages. And, yes, fill it up and minimize the condensation space.