Old Fuel

[eze2bme]

I have two fuel (diesel) tanks on my 43DC; a 92 gallon keel tank and a 283 gallon aft tank. The keel tank was filled two years ago and I haven't used the fuel since. I did add stabalizer and biocide at the fill-up. I only run my boat about 150 hrs. a year a have been topping off the aft tank and adding stabalizer and biocide. I'm using the aft tank as it supplies the genny also.

This Spring I want to run from the keel tank to use some of this fuel. Is there anything I should do specifically since the fuel is two years old? I'll add DieselKleen as a precaution and watch the vacuum gauges on the filters.

Also, since I don't really need the additional keel tank capacity, is there any negative to running the tank almost dry - maybe down 75% - this would also be less weight I'm carrying around. (Just for info, I'm in South Carolina and use my boat year round in fresh water.)

Thanks for any thoughts.

 

[Trojan]

My 43 sat for 2 1/2 years with 150 gallons in each tank. Stabilizer was added when the boat was layed up by the previous owner. I added a water dispersant and and Dieselkleen. I also added 50 gallons of fresh fuel to each tank. I changed the filters and fired the engines up. I then ran the tanks as low as I could. After that I put in 100 gallons in each tank and ran that out. I then changed out the filters, filled the tanks and I was good to go all summer around 3000 + gallon. I changed the filters again about 2 months later just for kicks. I was just curious. A waste of time. I live near Toledo, Ohio. There was no signs of alige. I hope you have the same luck as I had using up the old fuel. Whichever way you chose to do.



BILL

 

[MikeP]

I had a forward waste tank that had been converted to fuel when the boat was new (1980). According to the previous owner, in the late 90's the tank was disconnected from the rest of the fuel system but still full - 105 gal - of diesel. We bought the boat in '04; the forward tank was still full of that fuel.

I pulled some up with a suction pump - it looked fine. I then conducted an extremely scientific test. I put some fresh diesel on a rag and lit it with a match. I put some of the old diesel on a rag and did the same thing. I compared how they burned side-by-side noted the smell and the smoke. Looked exactly the same.

I used a small automotive Holley fuel pump and 30 ft of hose to pump the 10-year-old fuel into the forward main tank. There was no effect on operation or the fuel filters.

I have no idea if any additives were put in the tank at any time previously. I put in a can of Diesel Kleen (I think that's what it was...) a week prior to pumping it over. Frankly I can't figure out why the stuff looked like new since diesel is supposed to degrade fairly rapidly. Perhaps there's more to the deteriorating fuel issue than just time. But I'm no chemist.

 

[ThirdHatt]

I thought it was gasoline that would "varnish" or degrade fairly rapidly, as opposed to diesel. I thought diesel would stay stable in tanks for some time, assuming algae or water is not allowed to contaminate. Think of all the boats that sit for extended periods of time. I keep my forward and mid tanks pressed and use the aft tank for cycling unless I'm on a cruise.

 

[REBrueckner]

Two year old fuel, especialy stablizied will itself be fine..the problem is you never know what else was in the tank when the last fuel was added. You should be able to run right from the old tank keeping watch on your fuel filters.
A precautionary safety step would be to get some water indicator (sold at marine stores) , place it on a stick, and poke the stick to the bottom of the tank..it changes color in the presence of water. You can also stick a pump out hose to the very bottom of the tank and pump into a five gallon container a few times,emptying the container into your other tank between fill ups...if no water/muck is present likely you are ok.

A greater degree of safety would be to pump the fuel to your aft tank via a clear hose section and monitor the color/content as you pump. When in doubt you can always fill a five gallon container along the fuel transfer process, let it settle a few minutes, and see if anything settles out...water,crud,particles, or nothing at at...Any water settles to the bottom.

 

[ADaily3224]

When I bought my boat it had sat indoors, heated storage, high and dry, for three years. The previous owner was unable to use it for a variety of reasons.
The service department at Walstrom Marine where I purchased the boat was as concerned about the fuel as I was. Upon launch it started right up and ran fine. The tanks were almost full. Performance was poor, lots of soot, and the throttles were very far forward to reach cruse RPM. After about 500 miles and several fuel stops, 200 gallons at a time added, it started to run better and the performance improved dramatically.
By the time the boat was home there was no soot, it ran beautifully, and the filters never needed replacing. Fuel consumption dropped about in half after the first tank full was drained to about a third. I guess I can say that the level of power contained in old fuel is significantly less than new fuel. Not very scientific but factual.

Tony D

 

[Nonchalant1]

If you're in Florida, West Coast, etc. you can stop by a marina that has a fuel "polishing" cleaning service and just have it cleaned and replaced into either tank. These are big pumping and filtering machines that filter your fuel. Of course, it's not cheap, but it solves you concerns. Genesis and a few others have built their own fuel polishing machines from fuel pumps, hoses and filters.

Doug