Sticky Fuel - new advice on fuel storage

[Sailing steve]

When it comes to Insurance .. you never know what they are going to come up with next !!

Maybe one of their Underwriters had a 'sticky engine' on his boat ?? Who knows ....

Maybe the article is clickbait to draw people to the insurer's site and create an impression of what jolly good chaps the insurance operatives are and a demonstration of how much they really, really, really care. about their clients.

 

[NormanS]

So what proportion of Kero to add to diesel?

 

[Ammonite]

I've no experience with sticky fuel but I have had issues with what I think are asphaltenes, a dark brown oily residue that resembles used engine oil that can seperate out from the diesel under certain conditions e.g. long term storage, cold weather etc. Unlike bug it's not stringy and will pass through the filters and seperate out again in the tank. From what I've read it can lead to oily deposits in the cylinder head / poor combustion.

 

[Bouba]

The other part of the new advice is to drain water from the tank…not every tank has a drain plug

 

[Beneteau381]

I've no experience with sticky fuel but I have had issues with what I think are asphaltenes, a dark brown oily residue that resembles used engine oil that can seperate out from the diesel under certain conditions e.g. long term storage, cold weather etc. Unlike bug it's not stringy and will pass through the filters and seperate out again in the tank. From what I've read it can lead to oily deposits in the cylinder head / poor combustion.

I find that hard to believe. Most of our diesels will run on any “fuel oil” that will pass through the pump and injectors. So once through the injectors, it will burn and not leave oily deposits.

 

[Refueler]

So what proportion of Kero to add to diesel?

Depends on what you want to do ... it can be anything from a cupful to a typical sailboat tank of 50ltrs if temp rarely falls below -5c .... or up to 15% ratio if you expect serious -15c or so winter and fuel stays outside ..

Similar values if using gasoline.

Note that Nanuk Diesel used in Alaska is actually DPK (Dual Purpose Kerosine) ... a high grade Kero - not diesel

 

[Refueler]

I find that hard to believe. Most of our diesels will run on any “fuel oil” that will pass through the pump and injectors. So once through the injectors, it will burn and not leave oily deposits.

Asphaltenes are hard to burn actually ... but would not normally pass so far through system.

 

[Beneteau381]

Asphaltenes are hard to burn actually ... but would not normally pass so far through system.

Nigel, read my post again, “that will pass through the pump and injectors” That was the point of my post! The poster said oily deposits, and so they must have gone through the injector!

 

[rotrax]

Nigel, read my post again, “that will pass through the pump and injectors” That was the point of my post! The poster said oily deposits, and so they must have gone through the injector!

Oil from the crankcase can pass into the combustion chamber of any IC engine. These 'oily deposits may NOT be fuel related and may not have passed through the injector pump.

Just sayin.........................

 

[thinwater]

The other part of the new advice is to drain water from the tank…not every tank has a drain plug

Neither do the underground tanks at the petrol station, yet they do check for water in the tanks (this is law in the US, don't know about the UK) and sump the tank as needed.

The simplest way is to insert an oil pump-out suction tube through the filler or other opening to the bottom. Easy.

Another culprit is copper and brass in the system, which are known polymerization catalysts for diesel and are specifically called out in engine manufacturer guidance, as well as ISO and ASTM standards. A few fittings on the engine, but not lines or tanks. Read below.

Mostly, run the engine enough that the fuel is burned in a timely manner.
---
ASTM D975 Appendix X2.7.2: Fuel Storage Conditions
Copper and copper-containing alloys should be avoided. Copper can promote fuel degradation and may produce mercaptide gels. Zinc coatings can react with water or organic acids to form gels which rapidly clog filters.


Cat installation guidance.
http://pdf.cat.com/cda/files/3375312/7/Diesel+Fuel+Diesel+Fuel+Systems+LEBW4976-04.pdf
Material. Black iron pipe is best suited for diesel fuel lines. Steel or cast iron valves and fittings are preferred.

CAUTION: Copper and zinc, either in the form of plating or as a major alloying component, should not be used with diesel fuels. Zinc is unstable in the presence of sulfur, particularly if moisture is present in the fuel. The sludge formed by chemical action is extremely harmful to the engine’s internal components.


Cummins installation guidance.
https://www.cumminspower.com/www/literature/applicationmanuals/t-030_p115-132.pdf

Diesel Fuel Piping. Diesel fuel lines should be constructed from black iron pipe. Cast iron and aluminum pipe and fittings must not be used because they are porous and can leak fuel. Galvanized fuel lines, fittings, and tanks must not be used because the galvanized coating is attacked by the sulfuric acid that forms when the sulfur in the fuel combines with tank condensate, resulting in debris that can clog fuel pumps and filters. Copper lines should not be used because fuel polymerizes (thickens) in copper tubing during long periods of disuse and can clog fuel injectors. Also, copper lines are less rugged than black iron, and thus more susceptible to damage.

Note: Never use galvanized or copper fuel lines, fittings or fuel tanks. Condensation in the tank and lines combines with the sulfur in the diesel fuel to produce sulfuric acid. The molecular structure of the copper or galvanized lines or tanks reacts with the acid and contaminates the fuel.


Yanmar manual
Marine & Industrial Engine Distributor | Mack Boring & Parts Co.
piping is specified as rubber or steel (page 9).

 

[Ammonite]

I think the idea is that the asphaltenes clog the injectors which leads to poor atomisation and the oily deposits are a mixture of the resulting carbon and unburnt diesel

 

[Beneteau381]

Oil from the crankcase can pass into the combustion chamber of any IC engine. These 'oily deposits may NOT be fuel related and may not have passed through the injector pump.

Just sayin.........................

Possible BUT!

 

[rotrax]

Possible BUT!

But what? Very common situation. My 110HP Yanmar requires 1Litre of oil to top up each season. Where does it go? It aint in the undersump bilge. My view is some gets blown in with the turbo, some gets past the rings and valve guides.

It all goes into the combustion chamber, along with injected fuel.

Just sayin........................

 

[NormanS]

Depends on what you want to do ... it can be anything from a cupful to a typical sailboat tank of 50ltrs if temp rarely falls below -5c .... or up to 15% ratio if you expect serious -15c or so winter and fuel stays outside ..

Similar values if using gasoline.

Note that Nanuk Diesel used in Alaska is actually DPK (Dual Purpose Kerosine) ... a high grade Kero - not diesel

See post No 10.

 

[Refueler]

See post No 10.

Winter grades are usually going out to stations well before winter to ensure supply to consumers.

You can actually search online for the Specs against calendar for regions. Beginning of November is traditionally UK change over from summer to winter grade ... (Summer grade can be anywhere from -4 to -7C CFPP ... winter was required to be from -12C and lower with -15C common).

Many parts of EU carry -15C and lower for winter ... where I live its -25C or lower. Each region has a spec to maintain transport.

I have suggested gasoline or kero addition ...

But based on your #10 .... you are doing basically similar to myself ... my boat tanks carry summer grade through storage and come spring time and re-launch - all fires up fine.
My diesel does have Anti-Bug enzyme added by me as a standard through the season ... but this does not prevent cold problems. CFPP is due to paraffinic crystallisation ... basically it drops out of suspension and then blocks the filters .... BUT as the diesel warms up again - it starts to dissolve back into the fuel again ...
You can see this by inducing Cloud Point ... jam jar of diesel ... subject it to cooling ... summer grade at about -4C or so will start to become cloudy as the paraffins start to crystalise ... once you see that ... let the fuel warm up again and the cloudiness will clear ...

Cloud Point occurs a few degrees before CFPP but both are based on the Paraffins.