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Old 30-09-2011, 17:23   #16
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Re: Does Diesel Go Sour Over Winter

PRI-D to preserve rejuvinate diesel.

PRI-G to restore old stale gasoline.
I will add this, old gas can stick intake valve stems with a gooey varnish.
Even with PRI-G.

To fix old gas add the PRI-G and add Marvel Mystery oil at 10 ozs per 10 gallons.
The PRI-G does make the old gas run ok.
The MMO keeps the varnishes from gumming up carbs line and valves.
I know because I was having a problem with 7 year old gasoline. And after the PRI and the MMO it is working fine.

The MMO is a mix of mineral oil and naptha. The mineral oil keeps the varnishes from sticking to the metals when the fuel dries on the parts..

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Old 30-09-2011, 18:47   #17
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Re: Does Diesel Go Sour Over Winter

You would be surprised what you might find in the fuel tank even if you use a biocide like I did when I had a diesel on board:
THE BIANKA LOG BLOG: IN THE TANK: Part One, Scene of the grime!

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Old 30-09-2011, 19:08   #18

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Re: Does Diesel Go Sour Over Winter

Pull a cheap condom over the vent fitting. Simpler cheaper faster. Proven to keep moisture out of gun barrels by millions of grunts. Can expand and contract with temperature changes.
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Old 30-09-2011, 20:19   #19
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Re: Does Diesel Go Sour Over Winter

The environmentally improved diesel of today (at least in the US) is a very different formulation from even a few years ago. These additives do break down. Low emission high compression diesels also are much pickier about fuel than slow turning naturally aspirated diesels. As a result, I no longer fill in the fall but wait until spring after the marina has gotten a new tanker load to be sure of fresh fuel. I also add FPPF additives (approved by Yanmar) to any fuel that spent the winter to restore lubricants and cetane.

The traditional reason to fill the tank was solely to reduce condensation that encourages the growth of algae. Fortunately, algae grows very little in the cold of winter. I also run the fuel through the onboard polisher at layup and then twice more during the winter. Each time I add a small dose of biocide.

Could I get away with less? Probably. But in my last boat, clogged fuel filters were a constant source of stress and at times genuine danger in rough conditions. I never knew when the engine might die from fuel starvation after junk got stirred up in the tank. With this boat, I've never had a moment's problem.

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Old 01-10-2011, 09:58   #20
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Re: Does Diesel Go Sour Over Winter

IMO we have the worst fuel ever and it does affect public safety.

Diesel grows bugs because their is some water in the fuel.
When you tell people that diesel fuel grows algae and bacteria they think your crazy.
Those people dont do much diesel boating.

some interesting pictures of diesel bugs
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Old 01-10-2011, 10:41   #21
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Re: Does Diesel Go Sour Over Winter

quite a few years ago yachties would stop off at places like palmyra,kanton and johnson atolls that had formerly been us bases during ww11 and fill their tanks from fuel that had been left there when the bases were abandoned.
some of that fuel was 30-40 year old diesel!!!!!!
my catamaran building project updates
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Old 02-10-2011, 17:47   #22
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Re: Does Diesel Go Sour Over Winter

We clean fuel tanks everyday and our findings vary from tank to tank.

What we find in vehicles/vessel with either gas or diesel that have saddle type tanks (one port/one stb'd or one driverside/one passenger side) is one tank has much higher chance of a greater contamination issue. This is usually due to the orientation during the idle periods, while in a slip, parking lot, etc. One side will see a greater difference in temperature changes therefore we find more contaminates there.

When we clean a diesel fuel tank, we can tell if the owner has been using a biocide. Our findings is a small coffee ground size granular - dead bugs. Once these little devils get to your racor, the filter will plug and you are shutdown.

The bugs are microbial growth that exist due to water/condensation in the tank. What most biocides do is kill the bugs but however very few minimize or eliminate the water, therefore the bugs come back. I repeat this store everyday "if you have moles in your yard, all of the traps and poison will not stop the moles. You have to eliminate their food source, the grub worms and beatles in the soil." The water is the food source for microbial growth (A.K.A. bugs, algae, etc).

So does diesel go sour over winter? Each tank is different, mostly depends how it has been cared for. Usually healthy diesel will endure a season of being layed up. And as always, treat the fuels when they are fresh. No fuel additive can make wine out of sour grapes.


"Suckin Sludge & Havin a Gas"
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