Full fuel tank over winter ?

[tsekul]

I usually fill my polypropylene tank (40ltrs) during winter layup. But with the issues around bio diesel I am wondering whether or not to bother ?

We run a small tube heater and dehumidifier when ashore.

We barely get through a tank in a season as we mainly race. We use the engine primarily to potter at the beginning and end of racing.

This means we could have diesel in the tank for the whole year or more. Usually treat it when we top up.

Any thoughts
T

 

[Cariadco]

In all the years I've had a boat in Corfu, I've never filled the tank at the end of the. season.
I have never had problems with dirty diesel or the dreaded Bug.
Since Bio Diesel came out, I have been adding additive to the fuel. Initially I used Marine 16 but that's got so expensive, I now use another type. Sorry but can't remember it's name but it works perfectly.
My current boat has an 80ltr Aluminium Tank, and I change both the Primary and the Engine Fuel filters every 2 years.

 

[Mistroma]

I also have a polypropylene tank in my boat and stopped leaving it full a few years ago, pre-Covid. I try to leave it pretty empty and don't ever find signs of water from condensation. It can get pretty cold and wet over winter, even in Greece.

I dose with Marine-16 at end of season and extract any sediment from tank sump a week after lifting and again before launch. No sign of water so far.

I think it is very important to check the seal on the deck filler. I grease the o-ring and make certain excess squeezes out when tightening the cap. Heavy rain running down the deck will allow a lot of water to enter if the seal is not good.

 

[Amlov]

I use white diesel and simply pump it out to use in the car over winter. It’s just a bit painful to fill the tank up again in spring.

 

[B27]

This winter I'm going to totally empty and clean my tank.
I want to change some fittings anyway.
It's an old boat, there is a little crud in the bottom of the tank but I've removed what I can.
Modern diesel and petrol don't seem to keep.
I use white diesel so any I remove can go in the car, via a filter.

Last winter I ran the tank down and put my reserve cans into the car, so I know I'm starting the season with majority fresh diesel.

The same with the outboard, I only buy 2 litres of petrol for it at a time, that seems to be several months' worth.

 

[vyv_cox]

Before covid appeared I left my boat with the diesel tank 3/4 full. Three years later I returned, engine started immediately and ran well until all that fuel was consumed a month later.

I use no additives but I ensure that no water gets into the tank. Bug grows at the interface between water and fuel. Most water enters by leaking through the filler cap. Condensation in a small tank is negligible or non- existent.

 

[V1701]

I've 2 x 215L plastic tanks, the diesel in there was getting on for 5 years old & has given no issues, engine is run up regularly under load. Both tanks were down to 25L so I've just added another 25L to each tank just to get some "fresh" fuel in. I think the key here is plastic tank(s) & diesel. My boat is always in the water though - the sea keeps the temperatures in the boat, especially in the bilges & engine compartment, well above freezing even if it's freezing outside...

 

[Mark-1]

Bug grows at the interface between water and fuel. Most water enters by leaking through the filler cap. Condensation in a small tank is negligible or non- existent.

Thanks. This is interesting and perhaps explains why diesel cars that see little use don't seem to suffer. Boats frequently have a fuel filler underwater/facing upwards in rain. Cars less so. (I have a diesel van that's had less than two tanks of diesel since March 2020 and it runs fine.)

Is that logic correct?

 

[tsekul]

Thanks for the input.
My filler cap is under a tarp during the winter . I think I’ll not top it up this year. I’ve never seen any water in the water separator or fuel filter. Also means I won’t be carting 40litres of fuel round the course.

 

[Refueler]

Thanks. This is interesting and perhaps explains why diesel cars that see little use don't seem to suffer. Boats frequently have a fuel filler underwater/facing upwards in rain. Cars less so. (I have a diesel van that's had less than two tanks of diesel since March 2020 and it runs fine.)

Is that logic correct?

If you think cars do not suffer ... think again.

The main reason road vehicles are not often seen with trouble - is that 1. the tank is usually regularly filled / emptied in use .. 2. fuel filters regularly changed long before they are actually used up.

I had serious issues with an employee when he failed to maintain our Mercedes Truck. Stupid thing is that Truck was our Additives truck with pump / generator / containers of additives ...

Myself and another used the truck to empty one of our offices and transport the furniture across Baltic to another office. During the trip - the filters blocked with 'bug' and we limped home in short hops .... till finally we had to call out a mobile mechanic to clear the system.

To say embarrassing is understatement ...

 

[Mark-1]

If you think cars do not suffer ... think again.

The main reason road vehicles are not often seen with trouble - is that 1. the tank is usually regularly filled / emptied in use .. 2. fuel filters regularly changed long before they are actually used up.

I had serious issues with an employee when he failed to maintain our Mercedes Truck. Stupid thing is that Truck was our Additives truck with pump / generator / containers of additives ...

Myself and another used the truck to empty one of our offices and transport the furniture across Baltic to another office. During the trip - the filters blocked with 'bug' and we limped home in short hops .... till finally we had to call out a mobile mechanic to clear the system.

To say embarrassing is understatement ...

That suggests the water *is* condensation???

 

[vyv_cox]

Thanks. This is interesting and perhaps explains why diesel cars that see little use don't seem to suffer. Boats frequently have a fuel filler underwater/facing upwards in rain. Cars less so. (I have a diesel van that's had less than two tanks of diesel since March 2020 and it runs fine.)

Is that logic correct?

Yes I think so but you also need to ensure that water does not come in with the fuel. Floating bunkers in marinas are infamous for contaminated fuel. This can even be a problem for filling stations ashore.

 

[Fimacca]

I only fuel up from a well used (mod plod and ferries) marina who also treat their fuel. I try to cycle through it but I don't do much motoring so I treat it again if loitering for too many months.. I did purchase an endoscope to have a good look into the tank as its very inaccessible. All looked clean to me. I use the boat all winter so just keep it cycling through.

A friend had bug in his spare 20ltr tanks that had been filled up with white 2 years ago. (untreated) I asked what he did with it and he said he filtered it and put it into the boat tanks. I hope that was a very special fine filter......a Risky strategy imho !

 

[vyv_cox]

That suggests the water is *condensation*???

Here is the truth on condensation. Does an Empty Marine Fuel Tank Condensate? - Marine How To

 

[B27]

Here is the truth on condensation. Does an Empty Marine Fuel Tank Condensate? - Marine How To

I love a good experiment, but does some bloke's barn get the same humidity as a boat on a river in Devon?

 

[Refueler]

That suggests the water *is* condensation???

No.

All diesel fuels have water content .... tiny - but there. In fact ALL petroleum has water content ...

Its not unusual for Petrol Stations to have water in bottom of their tanks ......... for years it was common for storage tanks in terminals to have water bottoms ....

 

[Refueler]

I only fuel up from a well used (mod plod and ferries) marina who also treat their fuel. I try to cycle through it but I don't do much motoring so I treat it again if loitering for too many months.. I did purchase an endoscope to have a good look into the tank as its very inaccessible. All looked clean to me. I use the boat all winter so just keep it cycling through.

A friend had bug in his spare 20ltr tanks that had been filled up with white 2 years ago. (untreated) I asked what he did with it and he said he filtered it and put it into the boat tanks. I hope that was a very special fine filter......a Risky strategy imho !

If he had dosed the fuel - then let it settle - its good to use.

 

[Momac]

I don't worry about whether the fuel tanks are full or not over winter and have not had any fuel issues.

Stainless steel tanks in my case with the present boat since 2014.

The boat consumes the equivalent of more than a full tanks worth of fuel April to September but dont run the tank below a quarter full before topping up.

I do use a fuel additive and have used various brands.

The present additive is a lubricant and fuel system cleaner ,not a bug treatment.

 

[wonkywinch]

Since Bio Diesel came out, I have been adding additive to the fuel. Initially I used Marine 16 but that's got so expensive, I now use another type. Sorry but can't remember it's name but it works perfectly.

The excellent diesel doctor man & wife, Chris & Sarah from the Clean Diesel Company came and checked our (new to us) boat that had little use over last few years. His advice was that a modern AWB doesn't suffer from diesel bug since the tank is usually black, sits away from the engine (temperature cycling) and close the hull with more stable sea water temps. You are more likely to have issues from modern fuel going stale than diesel bug. No more than half tank and ensure fuel gets burned rather than fill to the brim was his suggestion.

The additive he recommended is "Fuel Doctor". Available on Ebay etc.

 

[Refueler]

The excellent diesel doctor man & wife, Chris & Sarah from the Clean Diesel Company came and checked our (new to us) boat that had little use over last few years. His advice was that a modern AWB doesn't suffer from diesel bug since the tank is usually black, sits away from the engine (temperature cycling) and close the hull with more stable sea water temps. You are more likely to have issues from modern fuel going stale than diesel bug. No more than half tank and ensure fuel gets burned rather than fill to the brim was his suggestion.

The additive he recommended is "Fuel Doctor". Available on Ebay etc.

Well it takes all I suppose .....

If they really said that .... I can only wonder where they got that rubbish idea from ...

Colour has no part in it.
Temp can slow it - but not stop it.

Stale ? Its diesel !! It has to be pretty bad to stop it working !!

As to additive to use - it depends on what you are treating. If its preventative - then near all will work. If its treating a system that has grown and collected the dead gunge - then you need an Enzyme based....

"Excellent diesel doctor" ???????