Fuel Tank Cleaning?

[AaronJ]

My Hunter 30' sat for about 2 years while I was away, with a nearly fuel tank of diesel (20 gallons). I just had the injectors tuned and want to replace the fuel and clean the tank out. There's a guage on top I can remove with a 2 inch hole. Anyone have good ideas for cleaning or things to remember while doing it?

Thanks!

[cdennyb]

my experience with diesel stored for that long is one of water at the bottom. If you don't disturb the tank full (like heading out on a bad weather tack in 20 ft waves) you could slip a siphon hose in there and sample the bottom, any water would be removed for the most part that way and the remaining would be filtered and seperated in your filter assembly, you DO HAVE a filter water seperator like the RACOR model don't you?
For the most part, 2 years isnt that long. Keep a good close watchon those filters and drain the filter seperator regularly and try to run that tank almost empty before refilling with fresh fuel. You can add a fuel additive like DIESEL POWER, from Wal Mart for about $17.00 / gal. and that will help with any issues with the lubricating properties that might have become unstable over time.
For the most part, clean and water free, run it.

[AaronJ]

Thanks for the advice, cdennyb. I do have a Racor 110 filter/water seperator and a filter before the injection pump.

[gonesail]

i had some old fuel in my tank but it was only about 10 or 12 gallons. i pumped it all out into 6 gallon plastic tanks and took these to the hazardous waste facility. i used the same pump that i change the oil with. there was some crap that came out of the tank for sure. i put new fuel in and think my engine is happy now. ah the benefits of having a small tank. you might consider installing an inspection port.

[Cheechako]

I think the advise to not disturb the fuel and pump the very bottom out until it looks good is a great way to go. If your engine smokes, you may want to get rid of the fuel. As I mentioned in a recent post, my old trawler had old fuel in it and the seller had it tested, The test came back only about 60% combustible! The Perkins was smoking. It was pumped out and the smoke has cleared up. The Racor stayed pretty clean looking even though the fuel had very little combustion available.

[hugosalt]

Had been using hole for gauge to check/clean tank over the years...
One of my winter projects was to create an access panel to fuel tank...
used thick oversized rubber for top of panel with diesel resistant silicone
(used for gaskets and in fuel lines) then screws every inch or so around
perimeter.
With or without an access panel...you can pump out fuel, let sit and settle
for a few days...while you absorb the balance fuel/water in the bottom of
tank with a lint free rag.(on the end of a stick if no access panel) Then gently pour the top 3/4 or so of the fuel back into the tank through a filtered funnel....or just
dispose of fuel and replace with fresh....Cleaning the bottom of the tank of water
and any sludge will go a long way to piece of mind. Good luck...

[Inthewind]

First thing I would ask you is....what does your fuel filter look like? Is it black or any black looking snotty stuff on it? Have you had any fuel problems yet? The fact that your tanks were full is a good thing. The biological contamination needs air and water to grow and having full tanks makes it impossible for the living organism to grow. However if they were not completely full there is a possibility for contamination to exist.

Maybe your fuel was treated with a fuel additive, perhaps a biocide that kills the bacteria and prevents it's growth. With a twenty gallon tank, I would not be too concerned unless your fuel filter looks contaminated.

To avoid spending money on a fuel polishing bussiness (such as myself) and being that you have a small tank. I would recommend pumping your fuel into 5 gallon containers if your concerned about it and physically cleaning your tank if you have good access to it. You can also dip your tank with water finding paste and it will tell you the level of water you possibly may have in your tank. Add your own inspection plate with one of these...Seabuilt - Access Plate Systems

For the most part, if your fuel filters look clean and you don't have any water in them, and you have not been shut down at sea because of dirty fuel that get sloshed around and breaks it loose then don't worry about it.

I would recommend that you carry extra filters in the event that your engine shuts down (usually in rough water) due to contamination that breaks free from the tank when sea conditions are rough.

[Inthewind]

Also, for what it worth, I have seen a boat that motored away with fuel that was over five years old. Diesel has a much longer shelf life than gasoline. I often times remove so called old diesel from boats, turn around and dump it in my diesel van and it runs fine.

[neilrob]

When I bought my ketch she had been filled with 1800 litres of diesel treated with an algicide/conditioner and left on the hard for 6 years.
I asked the forum what to do about stale fuel and received varying responces from dump it to it should be ok.
I was going to dispose of the diesel but thought that I would have a sample tested (cost $400 Aust). The test summary stated "the fuel is in remarkably good condition for its age. Meets or exceeds all benchmarks".
So I took extra filters and brought her the 1100nm home. No problems at all - no additional filter changes required.
Im very glad I didnt dispose of what at that time was near to $3200 of fuel.

[forsailbyowner]

Had a friend at marina that had neat setup. He took fuel line ran it through water filter he bought at home depot then through diaphram pump then to wand made of copper tubing. Hed use wand to blow fuel around sides and bottom of tank to agitate and dislodge, first treat with shock treatment of biobor and add a qt trans fluid for each five diesel. Keep changing filter and recirculating till filter comes out clean. Pump is used for oil change pump afterward

[Extemporaneous]

Originally Posted by forsailbyowner

Had a friend at marina that had neat setup. He took fuel line ran it through water filter he bought at home depot then through diaphram pump then to wand made of copper tubing. Hed use wand to blow fuel around sides and bottom of tank to agitate and dislodge, first treat with shock treatment of biobor and add a qt trans fluid for each five diesel. Keep changing filter and recirculating till filter comes out clean. Pump is used for oil change pump afterward

I wonder if compressed air running through a wand submerged in the diesel fuel would work in similar way (to agitate that is)?

Extemp.

[Charlie]

I think a key question is how old is the boat. If the boat is more than 10 years you might want to consider putting access ports in the tanks and scrubbing them out. The ports can be purchased and are fairly easy to install. The problem is if you have baffles you need to drill holes to avoid them. Also what size are the tanks. Is it possible to take the fuel out of the tanks and put them in Jerry cans and then add fill the tank with new fuel but add some of the old fuel thru a baja filter.

Recently found a good way to rid fuel of water. I have a few 1 gallon clear glass jugs that come with the upscale apple juice. I fill the fuel into the jugs put the lids on them and then turn them upside down. the water settles to the bottom then I crack the lid a littleand the water escapes. as it gets closer to the diesel I hold it over a container and when I have pure diesel flowing thru I tighten the cap and I have waterless diesel. Not very high tech but I couldn't find anyone who would take water contaminated diesel. it worked.

[DeepFrz]

You don't want to use compressed air as this will just oxygenate the fuel and cause it to degrade even further. That is one reason why fuel returns should have an outlet that reaches to near the bottom of the tank instead of just dumping the fuel in at the top of the tank.

I think it is important to have an access panel that allows you to really clean the tank. Just because you have not had any problems with gunk plugging up filters or fuel line doesn't mean that it wont happen at the worst possible time. Being sure that your tank is clean is real peace of mind.

[Portobello]

I physically removed the diesel tank from my previous boat - and flushed, and flushed and flushed it through with diesel - till it literally glowed on the inside. Probably overkill but at least I knew it was clean - It did have a lot of gunge in it.

[Extemporaneous]

Originally Posted by DeepFrz

You don't want to use compressed air as this will just oxygenate the fuel and cause it to degrade even further. That is one reason why fuel returns should have an outlet that reaches to near the bottom of the tank instead of just dumping the fuel in at the top of the tank.

Makes sense, thanks.

Originally Posted by DeepFrz

I think it is important to have an access panel that allows you to really clean the tank. Just because you have not had any problems with gunk plugging up filters or fuel line doesn't mean that it wont happen at the worst possible time. Being sure that your tank is clean is real peace of mind.

Anyone have good method of cutting access holes into a diesel fuel tank so that not to many filings get into the tank (not sure I expect an answer)?
I've attached the fuel filter/polishing system that I've made and have installed into my boat.
I still want to install inspection ports but the fuel tanks are full. 100 gallons in one and 50 gallons in the other.

Regards,
Extemp.