Fuel Tank needs cleaning?

[dmksails]

I'm in the final steps of the refit for the sailboat I bought last year am now making sure the engine is up to spec. I have a 40-gal fuel tank with 2 large service ports. I opened one of the ports today and took a swab of the tank bottom - see attached.

The swab looks nasty. I've only put 10 hours on the motor since the purchase and have not had a problem with the engine. I changed the fuel filters when I bought her and at that time the filters looked fine. I did put a bio additive into the fuel when I filled that tank, which has remained 1 inch from the tank top while doing the refit.

Do I need to do a clean of the tank, or is this normal?

[Copacabana]

If you have access, then yes, you should clean the tank. If you can reach every corner, drain the diesel and clean it out well with rags and querosene. You have to remove all the growth and gunk. Then start again with new diesel with a bio additive to keep it clean.

[Olly75]

If you do scrub out by hand, cut a piece of hose to the length of the opening and then split it along its length and slide it onto the rim of the port.

Saves many cuts and abrasions on your forearm and elbow.......

[a64pilot]

While it hurts nothing at all to clean the tank, I think it’s normal.
I’d say most fuel tanks have a layer of asphaltene.
I think it hurts nothing to leave it there myself.

[DeepFrz]

Originally Posted by a64pilot

While it hurts nothing at all to clean the tank, I think it’s normal.
I’d say most fuel tanks have a layer of asphaltene.
I think it hurts nothing to leave it there myself.

I STRONGLY disagree. As someone who has had a clogged fuel line in a seaway I STRONGLY recommend that you clean the tank.

[a64pilot]

So you clogged lines with asphatene?
Not bio? I’ve had a line clog on me before, several times on delivery, but it was dead bugs, I’ve seen asphaltene discolor a filter, but never clog, anything is possible I guess.

[Regatta]

If you need to clean get a look ... already did this job
Sea4See - Hallberg Rassy 312 "Ellös" - The Diesel Tank Nightmare
https://youtu.be/QMLgebkCJxs

[AJ_n_Audrey]

Originally Posted by DeepFrz

I STRONGLY disagree. As someone who has had a clogged fuel line in a seaway I STRONGLY recommend that you clean the tank.

As someone else who has had a fuel line clog in a seaway, I installed dual Racors that allow me to polish the fuel while underway, and I'm able to switch from one filter to the other. I also now run my fuel through a water separator / filter when refueling, after I got bad fuel (leading to the clog). Live and learn; I never, never want to be coming in an inlet again and have the engine fail because of a clog. Fortunately the wind was favorable and I was able to sail in, but it could have been bad.

[MJH]

Originally Posted by dmksails

I'm in the final steps of the refit for the sailboat I bought last year am now making sure the engine is up to spec. I have a 40-gal fuel tank with 2 large service ports. I opened one of the ports today and took a swab of the tank bottom - see attached.

The swab looks nasty. I've only put 10 hours on the motor since the purchase and have not had a problem with the engine. I changed the fuel filters when I bought her and at that time the filters looked fine. I did put a bio additive into the fuel when I filled that tank, which has remained 1 inch from the tank top while doing the refit.

Do I need to do a clean of the tank, or is this normal?

Obviously a clean swab would have been ideal but it wasn't. My thought is that almost all tanks will show some sign of contamination, the question is how much and you don't know at this point of ownership. Cleaning the tank now will give you a baseline for the future. Alternately, checking your fuel filter after a reasonable amount of engine use will give you some idea of the contamination level. Sailing on a reasonable day will probably not dislodge enough to cause a problem, its when the boat is tossed around that the loose sludge elements get sucked up and can cause problems with the engine running. You can get the fuel cleaned but that doesn't clean the tank...I have had personal experience with that. So, if you clean the tank get the fuel cleaned as well before you put it back in.

Practical Sailor says Biobor JF is the best biocide to use but it has only a three year shelf life (I called the company for this info.) The manufacture date is on the bottom of the bottle so check all bottles on the shelf before you buy.

Good Luck.

~ ~ _/) ~ ~ MJH

[Ken Z]

clean the tank. When you get into rough seas the gunk will get stirred upand be suspended in your fuel to be pumped thru the lines to your injector pump thru a filter or two, then thru a very small hole in your injector. All of the above hate debris and eventually something or all will clog and the engine will stop. Debris will also work on wearing out your pumps. Biggest failure of a diesel is bad fuel.

[DeepFrz]

So you clogged lines with asphatene?
Not bio? I’ve had a line clog on me before, several times on delivery, but it was dead bugs, I’ve seen asphaltene discolor a filter, but never clog, anything is possible I guess.

Not sure. I didn't check it with bleach.

Alternately, checking your fuel filter after a reasonable amount of engine use will give you some idea of the contamination level.

Not so. When my fuel line clogged the filter was nearly new and clean. The clog happened at a 90 deg. bend in the fuel line and during some rough seas.

I really think it is prudent to keep your fuel tanks clean.

[jmschmidt]

Only ten hours run time is your problem. More running = cleaner fuel since fuel returned from the injector pump goes back into the tank and is self-polished, so to speak, when returned through the filers and the injector pump.

Is you fuel tank easily removable? If so, take it to a radiator shop, they will clean it for a fraction of the cost of hiring a fancy fuel polishing company, and do a better job. I learned this the hard way too.

[Billnpr]

Used bioside and still had the fuel line clog before the fuel even got to the filters. Thatwas after having the fuel polished less than a year earlier. I would recomend having the fuel polished by a recomended person. He will use the return line to pressure wash the tank.

[Pete7]

I had a couple wisps of asphaltene in the water separator so decided to open up the tank and found this. Rags, marigold gloves and a 2" wall paper scraper had the tank clean in an hour.

Don't mess about, drain the tank down and clean it, then you know for sure that it is clean.

Pete

[DeepFrz]

Originally Posted by Billnpr

Used bioside and still had the fuel line clog before the fuel even got to the filters. Thatwas after having the fuel polished less than a year earlier. I would recomend having the fuel polished by a recomended person. He will use the return line to pressure wash the tank.

I've seen to many reports of bad jobs. Do a search on the subject here on CF and see for yourself. I recommend you clean the tanks yourself. Then you know you have done a good job or not.