Fuel tank polishing

paul culver

Member III
I suspect I have something in my aluminum gas tank that is clogging the in-line fuel filter after about 3 hours of run time. I heard that a procedure called tank polishing is used to fix this. Has anyone been through this? Expensive? Done on the water or on the hard? Any and all info will be greatly appreciated.
 

G Kiba

Member III
I suspect you mean fuel polishing? Taken from an online definition.

Fuel polishing is the technical cleaning process used to remove or filter microbial contamination from oil and hydrocarbon fuel in storage. It is essentially the removal of water, sediment and microbial contamination from such fuels as diesel, red diesel and biodiesel.

I also suspect that you mean you need to have your fuel system cleaned from tank to injector. Not a lot of fun to do yourself and could be expensive if you have it done. All of us with diesel/gas inboards face this at some level of complexity as our boats age way past expectation. Think of it as an inevitible learning experience. I am sure you will get some good advice from the folks here. Best of luck and know you are in good company.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hi,
There is good information on this site about cleaning out fuel tanks if you do a search. Some have jury rigged a simple pump/hose and filter to polish the fuel, others have emptied fuel from the tank, cleaned the inside through an inspection port, saving lots of money. Professional fuel polishing can usually be done at the dock and doesn't require hauling the boat.
Frank
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
Sure, but consider that all fuel polishing is is running the old fuel through filters. Which is what your own primary filter does anyhow. There is no equivalent tank polishing--you have to get in there and clean the insides, which with an inspection port is easy enough. My definition of fuel polishing, with our small tanks, is to just discard the existing fuel and put in new.

You didn't say how often you have to change the filters. If filter blockage has only stopped the engine once or maybe twice, I would discard the old fuel and put in new, and expect it to happen again some day (probably after rough weather, which agitates the tank). No big deal if you know what it is and know how to change filters. And to avoid surprises, you can change filters prophylactically, on a schedule.

Yes, I installed inspection ports on my 50-gallon diesel tank and now I know it is spotless inside. But a viable alternative, even for a cruddy old tank, is to plumb two primary filters. When one clogs, you just switch to the other until convenient to change the culprit filter.
 

paul culver

Member III
I guess instead of tank polishing I should have said tank cleaning. Symptoms: engine dies on two year old filter, runs fine after filter replacement for 3 hours, then dies again. And yes both dies were in rough conditions. I'll put in another filter to confirm. And I will check the site for tank cleaning but suspect it will run afoul of what is allowed at dockside.
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
If the tank is relatively accessible, you might be able to remove the fuel gauge and power wash through that (and then pump out the result). Or carve out a port you can put your arm through. But then, I did that with diesel, and gasoline is different.

Pardon my interest in your situation, I have been there. For what it;s worth, I wound up convinced that clogged filters are usually a temporary thing, and almost normal, and of less concern than it might appear. That didn't; stop me from massive intervention, which may have been overkill.

 

racushman

Member II
Sounds like bad fuel, and my suggestion is don’t try to polish or clean it. Pump it out and discard it. Easy to do oneself - I recently did it.

From Walmart I bought the number of 5 gallon blue kerosene tanks I needed to match the amount of fuel in my tank.

then I got a 9 quart fluid extractor from amazon to suck the fuel out the inspection port. Nice feature of the fluid extractor is it will suck crud off the bottom of the tank.

replace all filters. Replace fuel with new.

list the fuel as a free item on Craigslist. Give away both fuel and the containers. Someone will happily take it.
 

Tin Kicker

Sustaining Member
Moderator
Symptoms:
engine dies on
two year old filter,
runs fine after filter replacement for 3 hours,
then dies again.
And yes both dies were in rough conditions.
So it died once on a 2 year old filter, ran 3 hours till in rough conditions when it quit the second time?

Either of these could have been either growth in the fuel or water when the tank gets tossed around. Check the fuel/water separator and closely look at the filter and you might find a clue between the two.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Once when I was operating our club dredge (Deere 150 hp diesel) I started my shift as usual by eyeing the big filter with it's clear bottom bowl. Being beside the engine and the whole area being not well lit and not very clean... I noted the uniform appearance of the discolored 'fuel' in the bowl, and went thru the usual checkoff sheet to start up. After it started, it rather immediately quit. Could not get 'er to fire again. So....

Looked Really Closely at the filter bowl and then opened the petcock at the bottom. Yup. nothing but (discolored) water! Later discussion revealed that the previous day the drum it was fueled from must have had a rain water leak around the bung on top. (Sigh...)
Fuel tank had ingested a quart or so with the 55 gallon fill-up. (Double Sigh...)

Took a fricken long time to bleed the fuel system with the little lever/flipper hand pump on the engine.
IF I had seen a line between the water and fuel in that bowl I would have drained out the water and things would been hunky dory. Interesting what you can see by really *looking*, as the saying goes! But I did not look intently enough.

The joke was that I had proven that the engine would NOT run on water!
Ah, if only......

So look carefully, with a strong light source. And do check the rubber O-ring on your deck fills occasionally.
 

1911tex

Member III
Once when I was operating our club dredge (Deere 150 hp diesel) I started my shift as usual by eyeing the big filter with it's clear bottom bowl. Being beside the engine and the whole area being not well lit and not very clean... I noted the uniform appearance of the discolored 'fuel' in the bowl, and went thru the usual checkoff sheet to start up. After it started, it rather immediately quit. Could not get 'er to fire again. So....

Looked Really Closely at the filter bowl and then opened the petcock at the bottom. Yup. nothing but (discolored) water! Later discussion revealed that the previous day the drum it was fueled from must have had a rain water leak around the bung on top. (Sigh...)
Fuel tank had ingested a quart or so with the 55 gallon fill-up. (Double Sigh...)

Took a fricken long time to bleed the fuel system with the little lever/flipper hand pump on the engine.
IF I had seen a line between the water and fuel in that bowl I would have drained out the water and things would been hunky dory. Interesting what you can see by really *looking*, as the saying goes! But I did not look intently enough.

The joke was that I had proven that the engine would NOT run on water!
Ah, if only......

So look carefully, with a strong light source. And do check the rubber O-ring on your deck fills occasionally.
Not a joke...I witnessed an aircraft incident with engine stoppage a few feet above ground on takeoff...no injuries other than the airframe. Pilot noted when doing the sump routine, all was clear.....however, all was WATER!

You are correct, no line between the water and fuel in the clear sump. Pilot faulted as noted by FAA, clear sump container indicates water, avgas is blue...needed a second, maybe 3rd sump !
 

paul culver

Member III
Thanks for the input. Every new headache is a learning opportunity. My new issue of Good Old Boat just arrived with an article on fuel tank cleaning. What timing!
 

patrscoe

Member II
I am what you call a expert at cleaning my fuel system - not by choice!
Similar to Christian's video which I have watched a few times before, installing a port in the fuel tank was essential for maintenance. Needs to be big enough to fit your arm in there to clean the tank.
I agree with the previous posts - unless it's a full tank, it would be better to just pump out the fuel from the tank, clean the tank thoroughly, check the pickup tube for clogs, replace all your fuel filters and start with fresh fuel. If it's really bad, you may need to replace your filters again after a few sails / motoring, if there is still contaminated fuel in the lines.

If you check my posts, I just went through this again within the last few months. Last year, I purchased a electric transfer pump, did a extensive research on polishing fuel, and rigged up a fuel polishing system to save 10 gallons of diesel. System costs me $200 all in. Yea, I know, 10 gal of fuel for $200....
This year, I purchased a $30 Tera pump from Amazon - cheap but worked fine. Placed it in my tank port, pumped out my fuel and gave the fuel away to a local farmer. Wiped down the tank and replaced all the filters. Your fuel pump can get clogged too but it is a screen and difficult to twist off the bottom access of the pump.
 

Kenneth K

Sustaining Member
Blogs Author
If your in-line facet fuel pump is old, you can replace it ($100) and keep the old one for a transfer pump. Even if its new, it's not a bad idea to keep a spare on board...
 

paul culver

Member III
Here's what was done by a pro:
Fuel removed
Access port installed
Water and sediment removed
Acetone cleaning
Purge fuel line up to filter
$625.00

He said the tank interior was actually in good shape considering its age and that I should use Sta-Bil additive and premium gas in the future.
 
Top