Fuel tank gunk

[drh1965]

The inside of my poly diesel tank is coated with black gunk. I have no way to access any of it except through the small sender hole.

If I use BIOBOR JF to shock it, how many times am I going to have to replace the 30micron Racor filter element? Am I better off just leaving it alone? Will the BIOBOR actually eliminate that stuff eventually?

Thanks.

[DaveyJones]

It's pretty much a fact of life.

Diesel is 5% water. Additives that cause water to drop out of diesel will result in water build up. Unless you have a good method of getting this water out it's worse than doing nothing.

Additives that disperse water are bad for your fuel system.
The ones that collect water are best if you have a separator and are best for the fuel system.


The interface between the water and the diesel is where the bugs live.

If outside temperature is cold and diesel is hot humidity can build up in the tank causing more water. A proper fuel cap is essential to keep condensation to a minimum. Also keeping the tank full as much as possible will help for condensation. A fuel cooler will help as well.

If it gets too bad you need to clean out the fuel system and start over.

If you take the tank out to clean it I have used ice in the tank before and it worked as good or better than anything else and it's not flammable.

[Alan Wheeler]

Diesel is 5% water. Additives that cause water to drop out of diesel will result in water build up. Unless you have a good method of getting this water out it's worse than doing nothing.

No that is not correct. Pure fuel oil is just that, oil. Diesel has a few other "additives". However, water is not one of them. I do not know of any "aftermarket" additive that disperses water. To disperse water, it would mean the additive was hydrophobic. David is correct about the bug growing between the water and fuel. However, that water can collect anywhere and hence the gunge growing around the tank walls. It is also true that dosing the tank with biocide can cause the gunk to float around and block up the filters and block them often. You have two choices. You carry a lot of spare filters, or you remove the tank and clean it thoroughly.

[GordMay]

Originally Posted by DaveyJones

It's pretty much a fact of life.
Diesel is 5% water...

As Wheels says, diesel fuel is NOT 5% water.
Many diesel quality specifications include specific limits* on water content of fuels.
* ASTM specifies a maximum of 0.05% by volume - that’s 1/20TH of one percent.
(? hence Davey's confusion ?)

[Pelagic]

As you know, the biggest danger of all that gunk sticking to the insides of your tank is that if you get out into rough water it can shake free and clog up the filters pretty quick. If badly infected with diesel bacteria and you just treat, the treatment kills the bug, but leaves almost microscopic hard kernels of the bug that can get past the secondary fuel filter and clog up the injectors.

Putting a duplex system of primary filters that you can switch over while underway is probably the cheapest solution to keep you out of trouble.

Larger vessels with contaminated fuel tanks and who are not fitted with their own Fuel centrifuges, hire a Fuel Cleaning Service to treat, centrifuge and flush the old fuel thru the tank at pressure, to clean out the gunk. Probably not practical for your size but maybe worth checking.

[billangiep]

If there is room you could install a 3" or 4" inch clean out port. I did just that on a buddy's tank using cork as a gasket beaded with "permatex".

[DaveyJones]

Originally Posted by Alan Wheeler

No that is not correct. Pure fuel oil is just that, oil.

Pure fuel oil would be nice. Actually there is no such thing as pure fuel oil.

There is water in diesel by the time you put it in your tank.

Fuel jobbers should put drop out in the fuel before it's loaded but this is still not 100%.

There is water in gas as well but much less of it.

I agree 5% is (might be) a bit high. Maybe I should have just said there is water in diesel.

Every time I check my bulk tanks there is.. well, lets just call it a butt load of water in it.

Diesel has a few other "additives". However, water is not one of them.

Not an additive. Just no way to get it all out.

I do not know of any "aftermarket" additive that disperses water. To disperse water, it would mean the additive was hydrophobic.

About half of the products on the market do exactly that. What I mean by disperse is to break up water into small particles allowing them to pass through the filters and through the fuel system.

This can get rid of normal (normal meaning what's it most peoples diesel) amounts of water in your tank thereby reducing the possibility of growth.

The thing is the water is then in the fuel injection system. Running this water through can cause injector problems. However the other problem is when you are not running the engine. The water can corrode the internal parts of the fuel system. Pump, lines, etc.

Perhaps we should just call it an emulsifier instead of a dispersant.

Demulsifiers are used in the other types of diesel treatment to collect water in a separator. These types are best for the fuel system. Instead of dispersing (or lets just say break up into smaller particles) the water that has collected in your tank (for whatever reason we decide to name it) it causes the water to not e able to break up into small enough particles to get through your filter system.

The demulsifiers are the type most manufacturers recommend. emulsifiers which normally contain alcohol will void the warranty on most diesel fuel systems. despite this fact there are thousands of people that use it.

So you need to decide. Use a demulsifier and collect the water in a separator close to the tank preferably, or use an emulsifier and have fuel system problems.


Check with RACOR and they will tell you which kind they recommend.

The filter system is designed to do a certain thing. Not much point in buying something to defeat it.

[drh1965]

Originally Posted by Alan Wheeler

It is also true that dosing the tank with biocide can cause the gunk to float around and block up the filters and block them often. You have two choices. You carry a lot of spare filters, or you remove the tank and clean it thoroughly.

I take it that the biocide might eventually do the job then?

Originally Posted by Pelagic

If badly infected with diesel bacteria and you just treat, the treatment kills the bug, but leaves almost microscopic hard kernels of the bug that can get past the secondary fuel filter and clog up the injectors.

Putting a duplex system of primary filters that you can switch over while underway is probably the cheapest solution to keep you out of trouble.

A duplex system is just a pair of primary filters that can be run in parallel or bypassing one or the other, correct? I take it that you advocate leaving the tank alone and just adding the extra primary so that in if a slab of crud falls off and gets sucked up, I can bypass the primary that gets blocked? I plan to add a second Racor regardless but I want to make sure I understand what you are saying.

Originally Posted by billangiep

If there is room you could install a 3" or 4" inch clean out port. I did just that on a buddy's tank using cork as a gasket beaded with "permatex".

I have three problems with cleaning the ~20g tank:

1) No cleanouts

2) No large enough flat areas to add any cleanouts.

3) The tank is "tabbed" into the hull. I'd have to cut out all the fiberglass tabs to get it out. Then, I'd be afraid that the tank might crack or deform removing it. Then, it would be hard to resecure it I imagine.

So, if I go the biocide route, should I switch to a 2micron primary filter element? Does the biocide basically kill off everything the first time it is added? If so, could I just kill off everything and pump the tank back out again?

I relialize you guys may never have let your tanks get this bad but I appreciate your guestimates as well.

Thanks for all the help.

[Pblais]

A duplex system is just a pair of primary filters that can be run in parallel or bypassing one or the other, correct?

I have that. It's sort of a pain but what happens is the engine RPM's start going down then back as the throttle stays where it is. Might take a half hour and eventually it stops. You wait and then you restart. This process goes for a bit then it all fails. In between you go down below flip two valves and continue until that filter gets trashed. Once you have a tank that bad changing filters becomes the process you follow.

Tanks do not get that bad over night or even in a matter of weeks. It takes months. It happened to me bringing the boat home when we first purchased it. Not uncommon actually if you buy a boat in a cold climate in an area where they always haul the boats for sale. Sitting on the hard all winter can do it if additional time is added.

Adding a biocide after your tank is trashed is pointless. So what if the stuff clogging the filters is alive or dead? Using it to prevent it may help. Using up all your fuel in a timely manner is better and more fun!

[delmarrey]

Originally Posted by drh1965

I take it that the biocide might eventually do the job then?


A duplex system is just a pair of primary filters that can be run in parallel or bypassing one or the other, correct? I take it that you advocate leaving the tank alone and just adding the extra primary so that in if a slab of crud falls off and gets sucked up, I can bypass the primary that gets blocked? I plan to add a second Racor regardless but I want to make sure I understand what you are saying.



I have three problems with cleaning the ~20g tank:

1) No cleanouts

2) No large enough flat areas to add any cleanouts.

3) The tank is "tabbed" into the hull. I'd have to cut out all the fiberglass tabs to get it out. Then, I'd be afraid that the tank might crack or deform removing it. Then, it would be hard to resecure it I imagine.

So, if I go the biocide route, should I switch to a 2micron primary filter element? Does the biocide basically kill off everything the first time it is added? If so, could I just kill off everything and pump the tank back out again?

I relialize you guys may never have let your tanks get this bad but I appreciate your guestimates as well.

Thanks for all the help.

One of the problems I see is the tank is mounted to the hull allowing the temperature change and condensation build up. In the colder climates it's best to have a little air around the tank for insulation from dramatic temp changes.

Another option would be a to use a pressurized spray nozzle with cleaning agents down the sender hole and using a vacuum system to extract it out. This maybe something for a tank cleaning specialist but with the way yours is set up it maybe the best option (to pay a specialist)!

Chem's and filters would take a lot of time and effort, along with possible filtering problems. Sometimes it's just better to bite the bullet and get it over with!

[drh1965]

Originally Posted by delmarrey

Another option would be a to use a pressurized spray nozzle with cleaning agents down the sender hole and using a vacuum system to extract it out. This maybe something for a tank cleaning specialist but with the way yours is set up it maybe the best option (to pay a specialist)!

How would I find such a specialist? I've looked in the phone book and asked at West Marine but haven't had any luck...

I think finding competent repair people is the hardest thing about being a new boat owner (especially with a neglected 20 year old boat). I've only been able to find someone to help with the standing rigging. I've had to learn and do everything else. That might seem like a good thing, as I have learned a lot, but I'd love the reassurance of having an expert check my work. A good diesel mechanic would be an awesome find. Speaking of which, do diesel mechanics for boats work at the boat or do you have to pull the engine and bring it to them?

[S/V Elusive]

Darrell - mechanics will do which ever is needed - if a total rebuild, it would have to come out. As for fuel polishing - check around Clear Lake / Kemah for someone who does that. Most chandlers would know of someone. Check for pump out services - they often provide the fuel polishing service too.

[delmarrey]

I'll bet if you get into the Houston yellow pages under tank cleaning you can find some one or get a recommendation.

e.g. Gamajet Cleaning Systems, Inc - Industrial Tank Cleaning Machines and Equipment or even goggle "Houston tank cleaning".

And yes, diesel mechanics do work on motors in the boat if it's just minor repairs. You just have to make sure they are marine savvy!

[delmarrey]

Personally, myself as a machinist, I would rent a pressure washer and add an angled nozzle and use a wet vac to clean out the debris. I'm sure it would take several cleanings but that would work for ME.

[drh1965]

Originally Posted by delmarrey

I'll bet if you get into the Houston yellow pages under tank cleaning you can find some one or get a recommendation.

e.g. Gamajet Cleaning Systems, Inc - Industrial Tank Cleaning Machines and Equipment or even goggle "Houston tank cleaning".

I checked with them... they apparently clean tanks for large vessels at the Houston Shipyard.