Fuel Tanks

[Cobra]

Looking for some opinions here (dangerous I know!) on fuel tanks.
For the past two seasons we have been having serious issues with diesel bug in our 50 ltr stainless steel tank. Tried all types of preventative treatments but to no avail...usually 30 minutes motoring and power begins to drop off as the filters get clogged.
So, it is time to address the problem properly!
So, do I :-

a) remove the current tank and have it professionally cleaned
b) scrap the current tank and replace with the smallest available plastic tank
c) scrap the current tank and replace with a new smaller stainless tank

The tank is fitted to a Colvic 26 Sailer and in all honesty we only tend to use the engine getting on and off the mooring or going into marina's, so a 50 ltr tank is I think somewhat overkill.

Thoughts?

 

[westernman]

Looking for some opinions here (dangerous I know!) on fuel tanks.
For the past two seasons we have been having serious issues with diesel bug in our 50 ltr stainless steel tank. Tried all types of preventative treatments but to no avail...usually 30 minutes motoring and power begins to drop off as the filters get clogged.
So, it is time to address the problem properly!
So, do I :-

a) remove the current tank and have it professionally cleaned
b) scrap the current tank and replace with the smallest available plastic tank
c) scrap the current tank and replace with a new smaller stainless tank

The tank is fitted to a Colvic 26 Sailer and in all honesty we only tend to use the engine getting on and off the mooring or going into marina's, so a 50 ltr tank is I think somewhat overkill.

Thoughts?

You need a fuel treatment which not only kills the bug, but also dissolves it so it no longer clogs filters.
When I had the bug, I used Grotamar for this and it was very effective. No need to clean the tank.
I did not even need to polish the fuel or anything complicated.

I would pump out as much fuel as you reasonably can and dispose of it (the loss of 50 liters of fuel is more bearable than my 900 liters).
Then heavily dose the tank, put in a bit of fuel - say 1/8 full. If you have an engine which pulls much more fuel from the tank than it consumes and pumps the rest back to the thank (most yacht engines??), you can do this simply by running the engine for an hour or so.
Then pump out as much as you can again. There will always be a bit of fuel left in filters and pipes etc.

Then again dose the tank, change all the filters and fill up as normally. You should then be good to go.

Judging from Bouba's experience with fuel tanks, I certainly would not try to remove it or replace it.

 

[Sandy]

I'd remove the tank then clean it AND all the pipework. Tank removal might be a total pain in the ass depending on where it is. Thankfully, mine in a simple job. You might be surprised at the amount of crud in the tank.

Change ALL the filters. If your primary filter does not have a glass bowl change it to one that has. You can then at least see if there is any water/deposits in there.

Add fuel with a high dosage of something that kills the bug and gets rid of water.

Look at your filler cap, replace the O ring and grease the threads.

Run your engine hard for a couple of hours to ensure that the dosed fuel goes round the system a few times.

One tip I saw on YouTube was to get red jerry cans as you can see if there is any crude in the fuel you are using. I use a Mr Funnel to filter my fuel into my tank.

Check where you are getting your fuel from and if other boat owners have the same problem. After a dose of the bug I get my fuel from a filling station as their stock turnover is much higher than any marina.

 

[Boater Sam]

I would empty it, vac out all you can, Disconnect the fuel line and filters, clean them all thoroughly. Wash all off in acetone. New filters, make sure that they are bone dry.
Put a load of water and bleach in it, swirl it around and let it stand overnight.
Empty it and vac it out till dry, wash out with some acetone and vac it out again dry.

Put it all back together with bug killer and fuel, you will be good to go. Ensure that you are not getting water in anywhere, vents and fillers need seals and grease.
I have never met bug yet that will survive bleach and acetone.

 

[geem]

What's the access to the fuel tank like? We had some diesel bug but managed to kill it with Biocide then sucked the crud off the bottom off the tank using a cheap electric fuel pump, some clear hose, a cheap inline high volume filter and length of copper 10mm pipe that could be poked in the tank access lid hole and swept about until we no longer got the black stuff coming out. I now do this routinely every 6 months to check tank condition and remove and sediment. The engine fuel filters haven't suffered and I have not had to change them due to diesel bug.

 

[vyv_cox]

I have a stainless tank, never had bug and do not use treatment of any kind. I took the tank out a few years ago to replace the level sender and drain plug, there was a small amount of sludge in there, it was then about 30 years old.

It is water in the tank that leads to bug infestation. Ensure that none can get in by replacing a poor filler and resiting it if necessary.

 

[NormanS]

If you do fit a new tank, ensure that it has a dirt/water sump with a drain cock, and check it regularly. Any movement of the boat will ensure that any water or dirt in the tank will gravitate into the sump, from where it can be drained off.

 

[footsoldier]

So, do I :-

a) remove the current tank and have it professionally cleaned
b) scrap the current tank and replace with the smallest available plastic tank
c) scrap the current tank and replace with a new smaller stainless tank

Plenty of sensible suggestions already, but going back to the beginning - your listed options do not include cleaning the tank in situ. Is that an issue because of poor access?

Otherwise it seems a bit OTT to go to the expense and faff of scrapping an otherwise serviceable tank.

 

[PCUK]

If it hasn't got a decent access hatch, the first job is to fit one or more and then you can properly clean the tank.

 

[Cobra]

Thanks for your thoughts on this guys!
Having read of Bouba's saga with removing a fuel tank and having had a closer look at what can be done without major surgery, I have decided to go with a combination of Westernman and Sandy's (without the tank removal bit!) thinking.
Hopefully that will remove the problem and then with annual maintenance will not be recurring.

 

[Refueler]

Save me typing it all out again .....

Fuel bug!

With sensible approach and a syphon unit such as a Pela ... some empty clean containers and a decent ENZYME based additive - we can have you up and running without removing / changing tank etc.

I daresay you have been using the usually recc'd additive - which basically only kills the bug ... it then collects and causes sludge which gets sucked up and blocks the filters. Its a great additive ONCE you have got your tank basically free of gunge. But no good if you have a tank bottom already gunged up - you just add to it.
There's no need to waste the fuel you remove either ..... treating and decanting will save most of that fuel ...... and in fact heavily dosed as I describe - is a good item to put back to tank as its treated and saves wasting all that additive !!

 

[geem]

Save me typing it all out again .....

Fuel bug!

With sensible approach and a syphon unit such as a Pela ... some empty clean containers and a decent ENZYME based additive - we can have you up and running without removing / changing tank etc.

I daresay you have been using the usually recc'd additive - which basically only kills the bug ... it then collects and causes sludge which gets sucked up and blocks the filters. Its a great additive ONCE you have got your tank basically free of gunge. But no good if you have a tank bottom already gunged up - you just add to it.
There's no need to waste the fuel you remove either ..... treating and decanting will save most of that fuel ...... and in fact heavily dosed as I describe - is a good item to put back to tank as its treated and saves wasting all that additive !!

It's what I do but instead of a Pela I scrape the bottom of the tank with a copper pipe and fuel pump, sucking up the crap that likes to stick there. Run it through a filter and back to the tank. The first 1 pint of fluid goes in to a glass jar so I can check it for water and discard. I have full access to my 500 litre tank via a 600mm access lid but the 1 inch bronze screw cap plug in the top of the lid is super convenient for sucking out crap off the bottom without removing the lid.

 

[RunAgroundHard]

My advise having gone down this road is to remove the fuel and clean the tanks in place. I had the benefit of the tank top being accessible with a hatch to get a cleaning tool in. The tanks were drained of all fuel, there was a hard film in place (GRP tanks) which had to be scraped and washed off the tank wall. I used a contractor to do this, as I had two largish tanks. All sludge was removed. Refilled with new, clean fuel and dosed with something at the time. I cant remember what.

I would not keep the old fuel, or treat it, I gave it to a contractor about a barrel worth, 42 gallons. There was no way, after all that cleaning effort was I going to use dirty fuel again and I did not want to waste time settling or treating. That was over 5 years ago and no bug since then. I run my tanks down and refill at about 1/3 or based on next voyage requirements. I don't top up over winter. UK, Scotland West Coast conditions. I use a Pela to suck out water from the bottom of the tank, low corner, from time to time, about twice a year. I don't test it, just suck up about 1/2 a gallon and dump that into the marina oil recycling tank, therefore cant comment on water, sludge contents, I just see it as a preventative measure.

Keep an eye on the O rings or rubber gasket on the filler cap. They do wear out, flatten or loose their tenacity to seal so require replacing.

My personal opinion would be don't remove the tank, use what you have, just clean it. As others have said, fit an access hatch if you cant get inside. I actually decommissioned one fuel tank, post cleaning, as my coastal sailing requirements simply did not need that amount of fuel to be lugged around. This was more a cost benefit exercise than a volume threat and bug issue. I believe running down volume and allowing fuel to slosh around keeps the tank cleaner than maintaining brim full tanks as often as possible. It keeps the crud suspended and captured in the filters, rather than allowing it to build up over time in the tank sump.

 

[LittleSister]

. . . there was a hard film in place (GRP tanks) which had to be scraped and washed off the tank wall.

Did it really?

I have read of various people's endeavours in removing the stubborn deposits on diesel tank walls using, variously, chemicals, steam, elbow grease, etc., but wonder whether it is really necessary. If it's that hard to get off, can it really be much of a threat to one's fuel supply? (Unlike loose crud.)

I write as one who is contemplating (= dreading!) cleaning out a GRP tank with very limited access (to avoid future problems).

 

[geem]

Did it really?

I have read of various people's endeavours in removing the stubborn deposits on diesel tank walls using, variously, chemicals, steam, elbow grease, etc., but wonder whether it is really necessary. If it's that hard to get off, can it really be much of a threat to one's fuel supply? (Unlike loose crud.)

I write as one who is contemplating (= dreading!) cleaning out a GRP tank with very limited access (to avoid future problems).

Our tanks are grp. We last had the access lid off 10 years ago. The tank had an inch of sludge in the sump. That got cleaned off but the grp was stained red, presumably by the dye in the diesel. We cleaned it with a pan scrub but couldn't remove the red coating. We now only access the tank via the 1 inch plug in the lid for sucking out the sediment off the bottom of the sump twice a year. It was reassuring to inspect the tank 10 years ago but I now know I could have cleaned it satisfactorily with a suction pump.

 

[RunAgroundHard]

Did it really?

I have read of various people's endeavours in removing the stubborn deposits on diesel tank walls using, variously, chemicals, steam, elbow grease, etc., but wonder whether it is really necessary. If it's that hard to get off, can it really be much of a threat to one's fuel supply? (Unlike loose crud.)

I write as one who is contemplating (= dreading!) cleaning out a GRP tank with very limited access (to avoid future problems).

The way I thought about it was that the film was foreign, partially spread over the tanks walls, and tank cleaning was costing me a pretty penny, hence I wanted clean tanks. So off it came. Not all of it was hard, some was soft and washed off, some was hard and flaky. I have no idea what the stuff was, or even if it was relevant to bug. My tanks were spotless post cleaning but the GRP was stained from it's original colour, after the film was removed. Here you can see some of it.

 

[Caer Urfa]

Oh that brings back memories, I spent months and months with the problem you name it I did it to try and solve the problem various treatments to remove bugs, draining tank and hot jet washed out, new filters.
Not want you want to hear but from experience I would do the job properly once and for all, remove the tank and fuel pipes, I bought a new tank from Tek Tanks
Series C Fuel Tanks | Tek-Tanks
You can buy any size tank and fitting any additional fitting as I did, renewed all pipework with fuel grade rubber pipework and a new fuel filter and shut of valves etc.
No further problems fro 8 years ago.
One tip check your deck fuel filler does not let rain or seawater water in!!

 

[RunAgroundHard]

Did it really?

I have read of various people's endeavours in removing the stubborn deposits on diesel tank walls using, variously, chemicals, steam, elbow grease, etc., but wonder whether it is really necessary. If it's that hard to get off, can it really be much of a threat to one's fuel supply? (Unlike loose crud.)

I write as one who is contemplating (= dreading!) cleaning out a GRP tank with very limited access (to avoid future problems).

I was wondering how the contractor cleaned the tank but the receipt doesn't indicate how, just the scope of work. Apparently this stuff will remove deposits. Note that

Tank cleaner will disperse hardened deposits ...

Starbrite StarTron Fuel Tank Cleaner 1.9l

The US site gives images of the labels on the back giving more details, may be useful to the OP and yourself when cleaning your fuel tank.

Star Tron Tank Cleaner

 

[LittleSister]

I was wondering how the contractor cleaned the tank but the receipt doesn't indicate how, just the scope of work. Apparently this stuff will remove deposits. Note that



Starbrite StarTron Fuel Tank Cleaner 1.9l

The US site gives images of the labels on the back giving more details, may be useful to the OP and yourself when cleaning your fuel tank.

Star Tron Tank Cleaner

I see that at least some of the firms offering tank cleaning use steam jets.

The challenge in my case is that the access to the large tank is very limited - just a small plate that holds the fuel outlet, return and breather pipes. One could probably get an arm in, but not reach the whole of the tank nor see what you were doing.

The StarTron cleaner sounds interesting, except I'm doing it trying to avoid clogged filters, not precipitate them! I'd want to choose very carefully when to do it, so that anticipated following trips were least vulnerable to sudden engine expiry.

 

[Pete7]

but wonder whether it is really necessary. If it's that hard to get off, can it really be much of a threat to one's fuel supply? (Unlike loose crud.)

Until you can see inside the tank, there is no way of knowing. I have a large inspection hatch and with a wisp of black stringy stuff in the water separator decided to have a look inside. This is what I found

I used a 2" wall paper scraper to clean the tank out. I think the sides gloop is asphaltenes, on the bottom of the tank diesel bug. Replaced the filler cap and not had a problem in the past decade and last checked a year ago.

I suggest you put a Henderson hatch in the tank as a method of accessing the tank.

Pete