Is this bacteria?

[WE9V]

New to me boat has a ton of hummus-looking material in the bottom of the Racor 500. The boat was purchased with a full tank of diesel, and I was only able to consume about 1/4 tank in the meanwhile, but the engine starts and runs great. This material was in the bowl during the purchase, and (shame on me, I know) I used the engine for that 1/4 tank without cleaning it out, until now. Even after that 1/4 tank usage, the filter element looks new.

All of the photos I've seen here of diesel bacteria ("algae" - wrong, I know) is black and slimy. This is more like hummus or grits. I found a bottle of ValvTect BioGuard Plus 6 and DieselKleen in the lazerette, so I assume that he's treated the fuel at some point.

[JoeRobertJr]

My understanding is that sludge is mostly dead bacteria. The live bacteria thrive at the water/fuel boundary. Their carcasses sink.

[Shrew]

What kind of tank?

Here is an interesting reference to it that I found:

"You should check your filters for solids and water at least every six months and replace all filters no less than annually. If you see black solids that look like coffee grinds, black or brownish/tan fluffy solids similar to snowflakes or tan and/or cream colored slime you have a serious problem in the tank. At that point you should call a professional tank cleaning/fuel polishing company for help. Those problems can lead to premature engine wear and sometimes serious engine damage."

https://www.usafuelservice.com/ultra...r-diesel-fuel/

[JPA Cate]

Hi, WE9V,

Here's a hypothesis: the PO noticed he was having to change filters more often; so he bought the biocide and put it in the tank, and there was a big die -off. Now, with running the fuel, you've circulated it enough that you're getting fall out in the bottom of the filters, just as the PO began to, so he knew it was working.

Keep cleaning them out, and treating the fuel when you put more in, and keep cleaning out the sludge till it is no more. Expect to use a number of filters. The mass of sludge in the bottom represents a LOT of dead bacteria bodies, considering that one bacterium is microscopic.

Ann

[WE9V]

Originally Posted by Shrew

What kind of tank?

Aluminum

[JPA Cate]

Use the CF Custom Google Search and look for a thread about fuel tank cleaning written by Rustic Charm. He did his own, successfully. He's a nice guy boat owner.

Since your tanks are aluminum, you'll have to check whether you can use the same products he did. His boat's steel. The point is that it is an owner doable job, if you're so inclined. Otherwise you'll need to find someone reliable to do it for you. Harsh chemicals are involved.

Ann

[Fuss]

Originally Posted by JPA Cate

Use the CF Custom Google Search and look for a thread about fuel tank cleaning written by Rustic Charm. He did his own, successfully. He's a nice guy boat owner.

Since your tanks are aluminum, you'll have to check whether you can use the same products he did. His boat's steel. The point is that it is an owner doable job, if you're so inclined. Otherwise you'll need to find someone reliable to do it for you. Harsh chemicals are involved.

Ann

No harsh chemicals as he has an aluminium tank.


Best to open the inspection plate and clean it out, especially if its not a big full tank and its easy to do. A big full tank might need a very intensive work period.

I don't use any fuel treatment in my 20 year old tank ... for myself I would not change a running system...the filter gets a bit of brown stuff in it but not enough in the bowl to need draining.
The fuel polishing system is not powerful enough to stir up the contents so I have to rely on storms for that.

[CaptTom]

Keep up with the biocide and checking the filters. Clean and replace as needed. If your 1/4 tank usage left the filters clean, I'd say you're in maintenance mode. Clean the Racors and monitor over your next tank or two. Watch for water. Otherwise, as long as it doesn't get worse you're fine.

[WE9V]

Thanks everyone for your input. The bowl is very discolored, nearly opaque, so the previous owner may not have noticed the build up. The filter can be changed easily, but the bowl cannot be disassembled and reinstalled easily. It took me many hours to do so, using one of those endoscopes to see the bolts in order to see where to put the wrench. The bowl needs to be replaced with a new, clear bowl so further fouling can be easily seen and cleared. Darn bowls are $105 and an entire new Racor is only $290.

[CaptTom]

Well, $105 isn't a bad investment for something as critical as the main.

That said, if the filter stays clean, you can probably check the bowl less often. Another good investment might be a vacuum gauge. You can buy one which screws onto the top of the Racor. Good early warning system to avoid having to pull the filters as often.

[WE9V]

I removed the fuel sender, which is the only access hole, about 2" (50cm) diameter, and inserted a cheap amazon "endoscope" (turning out to be worth every penny for looking into tight places, where there's a lot of them on a boat).

The floor of the tank has more of this "hummus" looking stuff, but the walls are spotless. You can see the clear area around the pickup tube, and it's hard to see from the photos, but it's probably about only 1/16" thick. The walls are spotless, and look brand new.

I ordered a cheap diesel fuel pump, fuel hose, and several cheap inline fuel filters and will do my own fuel polishing, with a rigid tube manipulated in the fuel sender hole, to act as a vacuum cleaner to get as much of that stuff as possible now, before it gets into the Racor filter. Total cost for all the parts was $30.

[swisel]

The ONLY way to clean a tank satisfactorily is to get in there with elbow grease, cleaner and rags. This involves the installation of access ports for each baffle segment of the tank. The ports aren't cheap but they are available for either steel, monel or aluminum. The good thing is that the ports are there for the next time so, other than new gaskets, the job is a quick one.
You cannot clean a tank from the top with a magic wand nor can you find some magic emulsifying detergent that will do the job for you These things don't exist.