4 year old diesel

[Charlie]

So does anyone know whether cetane boost will help old diesel burn better

[Lepke]

Originally Posted by Charlie

So does anyone know whether cetane boost will help old diesel burn better

I use Archoil AR6200 that improves the burn, biocide, stabilizer, etc., and gives me about 6-8% better mileage.

[mvweebles]

I had a similar issue. Unfortunately, I do not have a good suggestion, just a story about how it worked out for me.

My trawler carries 400 gallons and the Perkins 4.236 85hp burns under 1-1/2 gph. I've had her for almost 25-years and last time I filled up was about 20-years ago - she's been sitting for years as a pied a Terre in SF. We aew getting ready to retire and cruise her, so it's time for a sorely needed refit. Last year, I decided to bring her from SF to Ensenda for a total refit which is underway.

I had about 150-200 gallons of roughly 20-year old fuel aboard. I can tell you diesel definitely has a shelf life - one side smelled more like linseed oil than diesel. I've used the same mechanic for well over 20-years and trust him. He strongly advised disposing of the fuel....... until he found out the price, which would have been at least $4000. I needed about 120 gallons to make the 500 nms run to Ensenada and part of the refit was planned to repair or replace the fuel tanks, so didn't want excess fuel aboard.

We decided to triple dose with Stanadyne (find it at Diamond Diesel in Oakland) which was also recommended by a friend who works for Deere Marine Propulsion. My understanding is its a fuel conditioner that helps keep asphaltines from precipitating out. I also added 80-gallons of fresh diesel.

I did about 20-hours of local sea trials and the engine ran fine so made the decision to just go for it. Ran about 75 engine hours straight through to Ensenada. The pressure on racors came up a bit and the clear bowls were dark as night from old tarnished fuel. I ran mostly on the tank that didn't smell as bad though.

I ended up replacing both fuel tanks so tried to unload the old fuel - 250 gallons, or over $1000 worth of fuel. Tried giving it away to the local fishing fleet. When they saw the fuel in a Mason jar, even they wouldn't take it. But my old Perkins ran fine with it. Doubt a newer Tier 3 (common rail) engine would.

[slug]

Originally Posted by Charlie

I just looked at my records and the last time I filled my diesel tanks was approaching 4 years ago. Two 35 gal tanks and down to 7 gallons. At the same time I put 10 gallons of diesel in 2 jeri cans which have lived in a cool lazaret in SF Bay. I am tempted to mix five gallons in each tank with 30 gallons of new diesel. But since it took 4 years to use up a full load of fuel I am hesitant to fill both tanks.

Any thoughts?

Also how do you dispose of diesel in the Grating State of Kalifornia?

Common practice..... no more than one year storage of diesel fuel

https://www.bp.com/content/dam/bp-co...age-diesel.pdf

[a64pilot]

Originally Posted by Charlie

So does anyone know whether cetane boost will help old diesel burn better

If its good stuff then yes, but there is a lot of snake oil out there.
In fact good defame booster has pretty much solved my smoky Yanmar.

[Charlie]

Originally Posted by mvweebles

I had a similar issue. Unfortunately, I do not have a good suggestion, just a story about how it worked out for me.

My trawler carries 400 gallons and the Perkins 4.236 85hp burns under 1-1/2 gph. I've had her for almost 25-years and last time I filled up was about 20-years ago - she's been sitting for years as a pied a Terre in SF. We aew getting ready to retire and cruise her, so it's time for a sorely needed refit. Last year, I decided to bring her from SF to Ensenda for a total refit which is underway.

I had about 150-200 gallons of roughly 20-year old fuel aboard. I can tell you diesel definitely has a shelf life - one side smelled more like linseed oil than diesel. I've used the same mechanic for well over 20-years and trust him. He strongly advised disposing of the fuel....... until he found out the price, which would have been at least $4000. I needed about 120 gallons to make the 500 nms run to Ensenada and part of the refit was planned to repair or replace the fuel tanks, so didn't want excess fuel aboard.

We decided to triple dose with Stanadyne (find it at Diamond Diesel in Oakland) which was also recommended by a friend who works for Deere Marine Propulsion. My understanding is its a fuel conditioner that helps keep asphaltines from precipitating out. I also added 80-gallons of fresh diesel.

I did about 20-hours of local sea trials and the engine ran fine so made the decision to just go for it. Ran about 75 engine hours straight through to Ensenada. The pressure on racors came up a bit and the clear bowls were dark as night from old tarnished fuel. I ran mostly on the tank that didn't smell as bad though.

I ended up replacing both fuel tanks so tried to unload the old fuel - 250 gallons, or over $1000 worth of fuel. Tried giving it away to the local fishing fleet. When they saw the fuel in a Mason jar, even they wouldn't take it. But my old Perkins ran fine with it. Doubt a newer Tier 3 (common rail) engine would.

Thanks for the anecdote. My fuel is clean. I plan on running it through a West Marine water separating fuel filter twice prior to putting it in my tanks. I will mix it with fresh diesel and add cetane boost.

I don't know if this is possible but the Red Oak Victory ship in Richmond has a boiler which they fire up. They can burn lesser quality fuel. You may be able to donate to them.

[FabioC]

I went through this last year (I even had a post here on CF asking for information) and eventually I was shown the difference: "old" diesel looks very different from good diesel, you just can't miss! If in doubt, just pour it in a clear container before filling the tank, if it is pink, it is good for sure. Old diesel (which btw would still work, but probably leave residue) changes color quite a bit. Also, if it has sediments, they are clearly visible.