Fuel polish, frequency?

[Fletcher500]

I just read the "I put water in my fuel tank" thread and the responses.

With that said, I was wondering how often folks were pro actively polishing?

Our previous boat was gas, and we have had oil burners for 2 years now. I have dual racors, and I am meticulous with the preventive maint on the fuel system. I add a biocide and booster at fill ups. Tanks are kept full.

Does anyone polish or do other things to their fuel system?

 

[bayview]

In 18 years in FL with same boat. Never polish, never add stuff, don't fill tanks unless I am going to use it all soon. never had a fuel problem

 

[O C Diver]

Most fuel problems can be summed up as follows:
Bad Fuel from supplier.
Missing or bad oring on fill cap.
Poorly located fuel tank vents.
If you solve / prevent these problems and have a good filter separator, water in the fuel really isn't a problem. While I do have a polishing system, it's use is more OCD prevention than need. If you are have water in fuel problems, addressing the cause is more beneficial.

Ted

 

[caltexflanc]

In 18 years in FL with same boat. Never polish, never add stuff, don't fill tanks unless I am going to use it all soon. never had a fuel problem

Yep, 7 years here, full time live aboards and cruisers, as the famous New Yorker cartoon said " ... How about never, is never good for you?" Granted, we had Detroit engines that cycle the fuel return heavily, and we bought clean fuel from high turnover suppliers. I never cleaned the Racor bowls either, no need for that either.

 

[Moby Nick]

Am reading encouraging news here. Thanks!

Our ASlbin-25 has her original Volvo-Penta MD17C and we've owned her 4 seasons with only one week-long cruise and several day-outings and a weekend or two aboard each season. This is my first experience with a marine diesel. I do have experience with a VW Rabbit Diesel, and a Dodge/Cummins 3/4 ton pickup Diesel which has a dual-fuel system burning waste vegetable oil (Albin's tow vehicle).

So the previous owner of our Albin talked like "polishing the fuel" was some sort of religion. The 12V polishing circuit was operating when we took delivery of the boat. Procrastination has caused me to have never polished the fuel since towing the boat home. Never had a fuel problem neither. Am presently rebuilding our boat's electrical system using circuit breakers instead of fuses. The polishing pump will be included with the circuit breakers instead of direct wiring off the house battery (without an on/off switch).

So it sounds like since we've always bought fuel from busy fuel docks, or large-volume truck fuel dealers, fuel polishing is nice, but not really required.

 

[bshanafelt]

I do agree that for a typical diesel powered boat owner that actually uses his boat regularly, a polisher is likely not needed.

I will polish maybe once a year for a few hours each tank. This is at the front of the season after my 'full' tanks have set over the winter. I also change the polisher filter each year, whether I polish or not.

I will say that my engine fuel filters, 2 racors + the engine mounted filter last a tremendous amount of time before I need to change them - 3 years for the last change a month ago and they looked very clean.

I like the setup also because the electric pump (Walbro) is great if I need to prime things. It is 'very' important to reset the valves to normal operating position when done priming - ask me how I learned this.

I installed the polishing system 14 years ago, soon after getting the boat and reading the now classic "Capt. Will's fuel polishing" article. Pretty easy to put it in and since I draw from the bottom of the tanks, I think any junk/water etc. will be captured.

 

[Bay Pelican]

We polish at least once a month and anytime we take on fuel. Usually I run it so that each tank is run through the filter four or five times. I can tell by the state of the fuel polishing filter and gunk that I drain from the filter housing that the polishing does some good. Better the water and gunk goes to the dump then to my engine.

Our polisher takes from the bottom of the tank and returns to the top of the tank so it gets the gunk and the water.

 

[BandB]

In day to day usage and coastal boating we polish infrequently although we do have extra filtration that many call polishing. To me, unless a centrifuge is involved I don't use that term. However, on a boat being used for serious offshore cruising and ocean crossing we have an Alfa Laval polishing system in use.

 

[Fletcher500]

In 18 years in FL with same boat. Never polish, never add stuff, don't fill tanks unless I am going to use it all soon. never had a fuel problem

I am surprised you have never had water in your fuel (condensation in the tanks) if you are not keeping your tanks full.

 

[sunchaser]

I am surprised you have never had water in your fuel (condensation in the tanks) if you are not keeping your tanks full.

Oh oh.

 

[markpierce]

Run my tanks to nearly empty before refilling. Haven't had a problem the five years I've run the boat. The fuel tanks have sufficient capacity to serve the boat for over 1.5 years.

 

[Fletcher500]

Oh oh.

No pop corn required. I am new to this site, but I have been on other forums for years and don't get involved in drama.

 

[BandB]

No pop corn required. I am new to this site, but I have been on other forums for years and don't get involved in drama.

Most here believe condensation in the tanks with diesel to be mostly an old wives or husbands tale. Water typically gets in through other means. You will find most TF'ers not concerned about leaving a half or quarter full tank.

 

[koliver]

If your area of use is well served with suppliers of clean fuel, you don't intorduce water or other contaminants, you keep your tanks full, you won't need to bother with polishing.
Old wives/husbands that have long memories can recall a time when the suppliers filled your tanks with lots of filth in the fuel.
In my own recollection, having fuelled in the same locale for 40 years, the fuel quality is very different now from way back then. I attribute this mainly to the Low sulphur diesel we now get at marine stations, of necessity much, much cleaner than the old high sulpher diesel.
The last time I changed my fuel filters, my log told me I had left the Racor 10μ filters 4 years and the secondary 2μ filters 10 years. In the old days I was lucky to get a year from each.

 

[caltexflanc]

Never a trace of water in our fuel. Tanks often run down to 1/8-1/4 in anticipation of a better fuel dock a little further on. Though I would note to those who wait years to change their Racor elements, the water shedding property of the elements degrades over time. I changed mine proactively once we cut down our cruising time at least once a year even if the vacuum reading was OK.

 

[FF]

It only takes a very small quantity of water in a tank to have a diesel/water interface..

It is the bug waste and bodies that stick to tank walls that can come loose and plug a filter.

Using a biocide is probably more important than endlessly pumping fuel thru a filter.

 

[Fletcher500]

Thanks for the feedback regarding tank levels. This is contrary to what I have read at other sources, but you are all experienced cruisers so I value your input.

 

[sunchaser]

IMHO most of our experiences are anecdotal. The smartest boat guy that has appeared on the Forum is RickB. He says keep the tank levels up during storage. Good enough for me, but maybe his mind has been changed with today's lower sulfur and maybe cleaner diesel.

RickB speak to us through a savant.

 

[bayview]

I am surprised you have never had water in your fuel (condensation in the tanks) if you are not keeping your tanks full.

i'm not because IMO that idea is mostly myth. Water comes with fuel or bad O rings or vents.

 

[MYTraveler]

Never polish and haven't used biocide in years. And typically go about 10 months between fill-ups (I fill-up at the end of every season, and usually once during the season). My filters (dual racors) get changed once a year, even though they are still very clean. I drain the bottom of the bowls before every major use, but rarely find anything there (even after letting the collection sit for a good while).

 

[Wxx3]

We polish at least once a month and anytime we take on fuel. Usually I run it so that each tank is run through the filter four or five times. I can tell by the state of the fuel polishing filter and gunk that I drain from the filter housing that the polishing does some good. Better the water and gunk goes to the dump then to my engine.

Our polisher takes from the bottom of the tank and returns to the top of the tank so it gets the gunk and the water.

Maybe Krogen thing since we have such big tanks? But I do exactly as Marty above.

Sometimes, the fuel is obviously very clean, as well as the tank and I stop after a few hours after fueling.

Sometimes, it's dirtier, but as much as it could be the fuel, it's usually the tank and what sits in the bottom inch. What's best is to polish in rough seas, I have and it picks up a lot of stuff, BUT having two tanks, I always know which tank is "better" and in rough seas, I use the better tank.

Tomorrow, I will be adding a full fuel load, almost 700 gal, so I will polish each tank for a few hours over the weekend, but don't expect anything much. If there is more than that, I'll keep polishing until there isn't.

All in all, for my type of cruising, the $500 I spent on the FP system was worth it as it also gave me a way to transfer fuel.

If you don't have a system and you are using a few hundred gallons a year if that, don't find problems you don't have.

 

[psneeld]

IMHO most of our experiences are anecdotal. The smartest boat guy that has appeared on the Forum is RickB. He says keep the tank levels up during storage. Good enough for me, but maybe his mind has been changed with today's lower sulfur and maybe cleaner diesel.

RickB speak to us through a savant.

Funny you should say that.....

Once and awhile in different marina heads, between the graffiti and "Kilroy was here" cartoons, I see one of his advice tidbits written down.

I think I saw his ideas on tank fills in one outside of Savannah and I copied it down...here it is....

"My general rule is keep the tank levels high to reduce the volume of air exchange due to temperature variations.

If you live in an area where the temperature/dew point spread is low and you park the boat with warm fuel tanks, you will draw in atmospheric moisture as the ullage space cools and it will condense on the tank walls.

That moisture may lead to corrosion of tank surfaces and it will increase the amount of suspended or free water.
It does not mean the sky will fall or your fuel will become a bug ranch and destroy your engine.

Keeping tank levels high will not cure warts or foot odor or improve the quality of your bow ornaments but it will minimize the risk of adding moisture to the fuel if you live in certain climates and have a pattern of operating that promotes regular and substantial air exchange in the tank. " RickB.....

 

[Wxx3]

Funny you should say that.....

Once and awhile in different marina heads, between the graffiti and "Kilroy was here" cartoons, I see one of his advice tidbits written down.

I think I saw his ideas on tank fills in one outside of Savannah and I copied it down...here it is....

"My general rule is keep the tank levels high to reduce the volume of air exchange due to temperature variations.

If you live in an area where the temperature/dew point spread is low and you park the boat with warm fuel tanks, you will draw in atmospheric moisture as the ullage space cools and it will condense on the tank walls.

That moisture may lead to corrosion of tank surfaces and it will increase the amount of suspended or free water.
It does not mean the sky will fall or your fuel will become a bug ranch and destroy your engine.

Keeping tank levels high will not cure warts or foot odor or improve the quality of your bow ornaments but it will minimize the risk of adding moisture to the fuel if you live in certain climates and have a pattern of operating that promotes regular and substantial air exchange in the tank. " RickB.....

Thank you Rick B and Paul.

 

[Baker]

And to the OP, I do not know how much your Volvo D6's pump versus how much they burn but there is a good chance that your engines and your current filters are doing a good bit of polishing as it is.

My Cummins pump 3-4 times more than they use....so the fuel goes thru the filter circuit often.

 

[Lepke]

Fuel polishing is just the newest income enhancing product for those that make and sell the systems. I've been running and rebuilding diesels for almost 60 years. I also worked in a family business that specialized in getting mothballed ships and boats running again. Often sitting for decades.
If you have Racors or similar, you're polishing the fuel as you run. Finer primary filters are available for most housings. I run 2 micron in mine. My Detroit mains circulate about 75 gallons an hour, so the fuel goes thru the filters many times. I buy fuel from places that sell high volumes of fuel and change their filters. Not some marina that has a different kid running the fuel dock every week. I change the primaries by vacuum reading and the current ones were installed in 2011 and the pair have about 2500 hours or thousands of gallons pass thru. The tanks are 1942 steel. I do use a biocide a couple times a year. Never had a diesel fuel problem in my life. And the new low sulfur fuel, like most EPA mandates, is crap.

 

[psneeld]

Well, for us Lehman 120 owners, they return almost no fuel.

Literally drops per hour.

The engine and Racor really aren't polishing...

Many will argue unless you have significant fliw or agitation...most engines really don't do much in the way of cleaning up a bad tank, but may keep good fuel good.

One issue is climate...never had a problem up north, first sailboat in flirida, the tanks turned to black goo pretty quickly till I started using Biobor.

 

[Fletcher500]

Burn rate on plane is about 213gph per engine. I have dual Racors, and watch the needle. They are high pressure, common rail, so yes, the amount of fuel flow is much greater than the amount delivered to the injectors, so I like your polishing analogy.

And to the OP, I do not know how much your Volvo D6's pump versus how much they burn but there is a good chance that your engines and your current filters are doing a good bit of polishing as it is.

My Cummins pump 3-4 times more than they use....so the fuel goes thru the filter circuit often.

 

[Fletcher500]

This was my understanding as well. If I wake up in the morning and see water/dew all over the boat, then the same argument can be made for the inside of a tank.

But, as I stated earlier, this forum has folks on it with many miles under their keel, and no problems with semi full tanks so I can appreciate their comments.

Personally, I try to keep my tanks full, and will not rely on them to cure my bad lower back.

[QUOTE="My general rule is keep the tank levels high to reduce the volume of air exchange due to temperature variations.

If you live in an area where the temperature/dew point spread is low and you park the boat with warm fuel tanks, you will draw in atmospheric moisture as the ullage space cools and it will condense on the tank walls.

That moisture may lead to corrosion of tank surfaces and it will increase the amount of suspended or free water. [/QUOTE]

 

[Fletcher500]

Woops, that was my other boat that I saw in a magazine last week. This one burns 13 gph per engine.

Burn rate on plane is about 213gph per engine. I have dual Racors, and watch the needle. They are high pressure, common rail, so yes, the amount of fuel flow is much greater than the amount delivered to the injectors, so I like your polishing analogy.

 

[markpierce]

My builder recommended against installing a polishing system, and my boatyard dismantled it. Nevertheless, am using its pump and piping to transfer fuel among tanks and to prime engine as needed.