Diesel fuel polishing...

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South of Heaven

South of Heaven

Guru
Joined
May 11, 2017
Messages
1,167
Location
USA
Vessel Name
Slow Lane
Vessel Make
2005 Silverton 35 Motoryacht
Im getting my new (to me) Camano 31 ready for launching in a couple weeks.

How important is fuel polishing for an older single diesel tank (2000)? It was treated last season at winterizing but the boat has not been used this year at all!! Except for the 2 seatrials we did this month.

Im really leaning towards having the fuel / tank polished. It seems like good insurance (not cheap insurance though!).

Going forward what should i be adding to the diesel this season?

What's the deal with algae growth? Should the tank be kept full when possible? Or are the algae concerns only for over the winter?

Algae -X system? Any good?
 
Greetings,
Mr. SoH. MY thoughts only. Fuel polishing is only merited IF a problem exists. Carry spare filters and know how to change them. A few runs out and about should bring any problems to light regarding YOUR fuel cleanliness. Until such time arises where you KNOW you have contaminated fuel, I'd hold off on the "polishing".

Personally, I would not add anything to your diesel except perhaps a biocide.

Algae does NOT grow in fuel tanks. Algae is a plant which needs sunlight to live. Few tanks are exposed to sunlight. There are animal microorganisms (bugs) that may live in any water in the bottom of the tanks but it is NOT algae. The biocide will kill any bugs that may happen to be in your tanks.

Algae-X? Again MY opinion...A gimmick designed to separate you from your wallet. A Racor system is much more cost effective.
 
Get the proper filters (3) ,change one now ,and learn to do it ,and get a racor vacuum gauge for the housing. Then go on a nice three hour cruise, lunch then back to the dock check gauge and see if it in the green,yellow or red. It tells you your filter is getting clogged. Keep a eye on that vacuum gauge for future filter changes.
 
As others have mentioned, have spare filters and know how to change them. The bowl of a Racor filter will tell you most of what you need to know. Go out on a rolly day and travel in beam seas. This will agitate the tank, giving you a representative sample in the Racor bowl.

Polishing the tank fuel doesn't guarantee the tank is clean. Having a good separator filter system is the best way to ensure the fuel going to your engine is clean. That's the most important thing.

Ted
 
I agree with all the above. In addition, get towing insurance from someone like TowBoatUS. In case you do have a problem, it is way cheaper to have the insurance rather than paying by the hour.
 
I agree with what the other have said.

I don't know what type of fuel filtration you have now. Do you have a single filter or a dual filter setup (not counting the on-engine filter)?

If you have a Racor turbine filter, then change the filter element and check carefully for any water/debri in the bowl. Drain off some fuel out of the bottom of the bowl and check it for water or clarity. If it is dirty, clean it out. Put in a new filter element.

I would also recommend running the engine for a couple hours afterwards and THEN change the on-engine filter.

At the least, figure out what filters you have and learn how to to change them. Then get a few extra filters and keep them in the boat along with any of the tools you may need to do the filter change.

Don't worry about about polishing fuel unless you notice that you are continually getting water in the filter or the filters clog quickly. The suggest for a vacuum gauge is an excellent one and I would do that ASAP if you don't have one already.

Then you shouldn't need to worry about your fuel at all.
 
Thanks everyone. Yes, I have a dual Racor setup. I also have Tow Boat US.

Can someone explain the vacuum gauge setup more? I'm coming from a single outboard, planing vessel.
 
Racor actually make a T handle with a gauge built into it now. The older style Racor gauges didn't have the. Handle and required a wrench to take the top off the filter. I just bought the new style gauge, haven't installed it yet but it looks like it will be great.
 
South of Heaven said:
Thanks everyone. Yes, I have a dual Racor setup. I also have Tow Boat US.

Can someone explain the vacuum gauge setup more? I'm coming from a single outboard, planing vessel.
Click to expand...



Most of the Racor dual systems that I have seen have a NPT port right above the fuel selector handle. If there is no gauge, then I would bet there is a plug there. You can get a vacuum gauge (get one with a drag needle) from your favorite marine supplier, remove that plug and screw in the gauge.

The vacuum gauge measures the amount of vacuum in the fuel line between the filter and the engine. Fuel is being sucked through the filters and then into the engine. The gauge measures the vacuum. As the filters get clogged, the amount of vacuum to draw fuel through the filters increases. This is what the gauge measures. Install the gauge with clean filters and run the boat. Run it up to the max power that you tend to the run the boat. Then with a drag needle gauge you can see how high the vacuum was. This is your normal point and in my experience is anywhere from 2-4 mmHg. Then you can periodically check your gauge. I do it it anything I am changing my fuel tank as the gauge is right next to my fuel manifold. If the vacuum starts to run 2-3 mmHg over the baseline, then I want to change my filter and/or switch to my other filter.

There are others here who will likely provide a more accurate description but that can get you started.
 
If you have excess water in your tank, you might want to check the gasket on your fill cap. We found ours was leaking water when it rained, ended up having to spend $300 to polish our tanks because a $1.25 gasket was cracked. Firefly is right, it's not a true algae, but it will stop up your filters pretty quick. We too have a single diesel with a dual system. We run on one Racor at a time just in case. If it gets clogged, we can switch filters and keep running while changing the bad one.
 
You can have your fuel tested for bugs. Drop a sample from the Racor bowl drain into the sample bottle and send it off to the lab. They'll do a culture and tell you if there's bacteria present.
I concur with all the other posts you've received, except that there's no real reason to treat fuel without a symptomatic cause. Ditto that the Algae-X is snake oil. All kinds of claims that the magnets in the device do all sorts of mysterious and wonderful things. No scientific proof.
There are a number of labs that do oil testing, I've used Lubriport Labs for over 10 yrs, do a good job at reasonable cost. No affiliation other than a customer.
 
Fuel polishing is a big song and dance that is only the process of circulating the fuel thru filters, usually an additive is included to help get the water out and breakup any sludge. Sometimes the fuel is heated. If you have a good primary filter like a Racor, you can do it yourself with an electric pump and a little plumbing. The pump can also help when you change the secondary filter and bleed the injector pump. If your engine pumps much more fuel than it burns, you polish as you run. My Detroit Diesels together pump 70 gallons/hour but burn 8+, so my day tank fuel is filtered many times. My tanks are so clean, I can run 2 micron primary filters. They last more than 500 hours. 500 x 70 gl/hr = 35,000 gallons filtered.
I put in an additive every fueling and have no sludge, water, etc. My steel main tanks were built in 1942. When doing a rebuild, I finally was able to access them and found the tanks clean, no water, no sludge. There was no cleaning to be done. I did have to weld up some pits in the bottom.
Algae-x is a biocide and works well. I used it in this boat (triple dose) when I bought it. The boat had sat for 6 years with no mothballing, care, etc. I later switched to Archoil AR6200 that I like better because it also has additives that improve the fuel burn in the lousy diesel we have to buy today. I get about a 10% mileage boost. My 3/4 ton, 4x4 Ford diesel PU gets 25 mpg with it.
 
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Dave Hays did a great job describing the Racor Vac gauge system but I would like to add the following. If you have an older Racor 1000MA or 500MA and you try to use the new SS tee handle with a gauge on top you may need to purchase a new lid for the filter housing. Parker Hanafin made the SS t handle without thinking about the older lid design. The brass T handle fits down into the lid while the SS T handle is much larger and the O ring will not seal. I got a great deal at $50 per T handle and gauge from 4Land4Sea and then found out I couldn't use them until I bought new lids. Th SS T handles have been superceeded by new brass T handles but are very expense. The older lids are cream colored and have ribbing on the top. The new lids are black and the ribbing is on the bottom. The gauge that comes with the SS T handle has a drag needle that allows you to see at a glance the condition of your filters.
 
Mostly good advice above especially what RT said. Keep it simple. In decades of diesel boating I have never used chemical additives.

try to keep fuel fresh by not always filling the tanks. Most diesels return lots of fuel to the tank so it is constantly "polished" . Low fuel levels mean that the fuel gets cycled through the filters more frequently. It also means that the fuel can slosh around more and stir up anything on the bottom. Keep an eye on your filters until your confidence in the cleanliness of the tanks improves.

If your racors have clear bowls shine a light through the fuel to judge its cleanliness and check for water. It should be ruby red and clear.

Have fun.
 
Is it a straight shot from the fill to the tank? If so draw some fuel from the very bottom of the tank. Let the sample sit for a few hours and see if anything settles out.
 
The big question , if the fuel is gunky is not weather the fuel in the tank can be cleaned , but how to clean the fuel tank.

THe bugs poop and die so there might be a thick layer of gunk on the tank walls.

This is not removed by "polishing" , regardless of what the tank filter guys claim.

IF its minor , a case of filters and a good filter change drill works.

If its bad in rough conditions sloshing fuel can break off chunks,, this can plug fuel feed lines.

If the tank can be removed , steam cleaning works.

If the tank is too hard to remove inspection / cleaning ports can be let in.

If you want to experiment , I talked to one owner that removed the fuel and used a couple of gallons of industrial cleaner and water to dissolve the gunk.

He used an air hose to bubble the mix at various fill depths.

Claimed a complete cure for almost no bucks , just some time.
 
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If you are planning to add a vacuum gauge, consider one of these

https://www.dentmarine.com/collections/frontpage/products/0-to-15-in-hg-vacuum-gauge-model-dm-15v

More expensive than the Racor gauge, but superior in a number of ways, and getting great reviews from early adopters.

Key advantages over the Racor gauge are:

1) Larger dial and face for easier reading.

2) Scale that better matches the acceptable restriction range of fuel filters

3) Far better accuracy in the range that matters.

More details available here

https://www.dentmarine.com/pages/frequently-asked-questions

Disclosure: I know the guy who makes these, but have no financial or other incentive or connection.
 
South of Heaven said:
Thanks everyone. Yes, I have a dual Racor setup. I also have Tow Boat US.

Can someone explain the vacuum gauge setup more? I'm coming from a single outboard, planing vessel.
Click to expand...

The vacuum gauge measures the resistance of the fuel flow through the filter. I used to change filters every year but I installed a gauge and now just change them when the resistance goes up (indicating that they are beginning to clog).

I would not bother with having the fuel "polished" and to properly clean your tanks would require cutting holes in your boat's floor to gain access to cutting holes in the tanks so a nozzle could be used to clean them.

I have a printed statement from Volvo stating that no fuel treatment is necessary. In the next paragraph, they recommend Stanadyne and one other brand of fuel treatment. Talk about talking out of both sides of the mouth at once.

I sometimes use the Stanadyne and sometimes don't. Some brands of fuel claim to be treated, some don't.

I keep my tanks full when not using the boat.
 
Delta Dog said:
If you have excess water in your tank, you might want to check the gasket on your fill cap. We found ours was leaking water when it rained,...................... .
Click to expand...

The location of the fuel fill caps on the Camano subjects them not only to water from rain and washing the boat, but to runoff from the flybridge. The condition of the gaskets is important.
 
Lepke said:
Fuel polishing is a big song and dance that is only the process of circulating the fuel thru filters,
Click to expand...

That is most definitely not fuel polishing and what most call fuel polishing, running through more filters, is not. If there is no centrifuge or similar equipment involved then it is just high level filtering, not polishing.

Fuel polishing can be extremely good and save a bad situation. Not something necessary if no problem is known though. We had a member here who got real polishing done recently in SC, but he had a definite fuel problem.
 
"they recommend Stanadyne and one other brand of fuel treatment. Talk about talking out of both sides of the mouth at once."

The Stanadyne is to clean the injectors , not to treat the fuel.

It does seem to work.
 
Thoughts and details from a marine engineer specializing in keeping marine engines clean and running well.....

Alfa Laval states that the centrifuge most often used by "fuel polishing" services is rated to capture "99 percent of particles between 2 and 5 microns." This is the same as a decent filter. A 2 micron filter will capture a great number of smaller particles, the actual number increases with use as the passages in the filter media become smaller.

Cummins states that the fuel used in their high pressure common rail engines meet the following standard:
"Cummins, in accordance with the Worldwide Fuel Charter, has specified a minimum fuel cleanliness
level 18/16/13 – measured by the ISO 4406standard. The three-number coding system 18/16/13 corresponds
to the number of particles of a size greater than 4, 6 and 14 microns per milliliter of fuel, respectively."

Bottom line ... a decent set of 2 micron filters will do just as good a job at "polishing" the fuel in a trawler's tanks as a centrifuge. The real benefits of a centrifuge lie in its ability to remove large quantities of water and suspended solids that would quickly clog a typical filter element. Those are uncommon conditions for the vast majority of recreational boaters operating in North American and European waters.

Tank cleaning by mechanical means (if and when required) followed by the use of an anti microbial additive, preventing water ingress, and attention to filtering is the solution to nearly all perceived fuel problems. A centrifuge (would probably) perform a larger role in owner bragging rights than maintaining fuel quality for 99 percent of Trawler Forum's readers."
 
psneeld said:
Thoughts and details from a marine engineer specializing in keeping marine engines clean and running well.....

Alfa Laval states that the centrifuge most often used by "fuel polishing" services is rated to capture "99 percent of particles between 2 and 5 microns." This is the same as a decent filter. A 2 micron filter will capture a great number of smaller particles, the actual number increases with use as the passages in the filter media become smaller.

Cummins states that the fuel used in their high pressure common rail engines meet the following standard:
"Cummins, in accordance with the Worldwide Fuel Charter, has specified a minimum fuel cleanliness
level 18/16/13 – measured by the ISO 4406standard. The three-number coding system 18/16/13 corresponds
to the number of particles of a size greater than 4, 6 and 14 microns per milliliter of fuel, respectively."

Bottom line ... a decent set of 2 micron filters will do just as good a job at "polishing" the fuel in a trawler's tanks as a centrifuge. The real benefits of a centrifuge lie in its ability to remove large quantities of water and suspended solids that would quickly clog a typical filter element. Those are uncommon conditions for the vast majority of recreational boaters operating in North American and European waters.

Tank cleaning by mechanical means (if and when required) followed by the use of an anti microbial additive, preventing water ingress, and attention to filtering is the solution to nearly all perceived fuel problems. A centrifuge (would probably) perform a larger role in owner bragging rights than maintaining fuel quality for 99 percent of Trawler Forum's readers."
Click to expand...

I agree with most of what he said. I do disagree with terminology and that is That is that where you say "polishing" in the fourth paragraph that is really "filtering."

You're correct that the majority of boats here don't need Alfa Laval, don't need a centrifuge. Occasionally one which has just been purchased or sat a long time and has problems needs it and in those cases if you're along the coast, you can find someone who can do it for you. We do have Alfa Laval, but only because we run off coast a lot, cross wide areas and purchase fuel in many places that we're not so sure of. We also run a bit higher performance engines that might be more subject to issues from bad fuel. We seldom see anything collected by the Alfa Laval system that is significant. Only twice that I remember and the Racors might well have handled it, although would have needed several very quick replacements due to the volume.

When you do have a serious problem in your tank, filtering protects the engines but doesn't get rid of the underlying problem. Polishing and cleaning can.
 
Also a bit of a difference if you're running, like we sometimes are, two gallons a minute of fuel versus 2 gallons an hour. Most boats requiring centrifuges are larger boats crossing oceans.
 
BandB said:
When you do have a serious problem in your tank, filtering protects the engines but doesn't get rid of the underlying problem. Polishing and cleaning can.
Click to expand...

I agree that cleaning the tank gets rid of the the core of the problem, but polishing is high volume filtering. They both achieve the same thing; filtering just takes longer.

Some engines filter faster than others. My Mitsubishi with electric fuel pump only uses about 3 litres/hour. But it draws about 15 litres per hour through the fuel filter and returns 80% of the filtered diesel back to the tank. By the time a tank is empty, the last bit of diesel has been filtered more than 5 times over. Its not polishing the fuel but the end result is the same.
 
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AusCan said:
I agree that cleaning the tank gets rid of the the core of the problem, but polishing is high volume filtering. They both achieve the same thing; filtering just takes longer.

Some engines filter faster than others. My Mitsubishi with electric fuel pump only uses about 3 litres/hour. But it draws about 15 litres per hour through the fuel filter and returns 80% of the filtered diesel back to the tank. By the time a tank is empty, the last bit of diesel has been filtered more than 5 times over. Its not polishing the fuel but the end result is the same.
Click to expand...

You can filter all you want but if there's a major problem in the bottom of your tanks, filtering will not clear it up. That's where a centrifuge is needed. Not needed for 99% here or most boats, but for that occasional issue, it's the only way to go.
 
FF said:
"they recommend Stanadyne and one other brand of fuel treatment. Talk about talking out of both sides of the mouth at once."

The Stanadyne is to clean the injectors , not to treat the fuel.

It does seem to work.
Click to expand...
The Volvo statement said nothing about fuel injectors, it mentioned low-sulphur fuel as the reason. We're talking 1999 here.
 
To The OP

I case it was not mentioned the vacuum gauges you want should have a needle that saves the highest reading because you may not be always watching them.
 
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