Do I need fuel polishing?

2006 Mainship 34T bought new. 2000 hours on the engine and ValvTect diesel fuel used almost exclusively.

Racor filter showed black on surface and needed changing sooner than previously.

Mechanic says this is algae growth in the tank and that I need fuel polishing.

I boat in the Pacific Northwest.

Comments?

Harlen said:

2006 Mainship 34T bought new. 2000 hours on the engine and ValvTect diesel fuel used almost exclusively.

Racor filter showed black on surface and needed changing sooner than previously.

Mechanic says this is algae growth in the tank and that I need fuel polishing.

I boat in the Pacific Northwest.

Comments?

Click to expand...

"Comments?"

Not nearly enough information for any valued answer.
- What is sooner than previously?
- How many gallons consumed since last filter?
- How did you know the filter needed changing?
- Vacuum reading?
- Did anyone open the tank and take a look?

I doubt that you need to have the fuel “polished” Harlem. I’d be interested in the answers to Smitty’s questions. I would also ask if you have ever seen any water in the Racor bowls?

You might want to use a biocide in your fuel tanks and then keep an eye on the filters, preferably with a vacuum gauge. If you have dual Racors, run on just one and see what the vacuum does, and if it goes up, then switch to the other and change the dirty filter.

Finally, does the mechanic offer “polishing” services?

The black is organisms or their waste. Obviously ValvTect isn't getting the job done. Fuel additives only last at most a year and the ones in new fuel may sit many months in a marina tank before you buy it.
I only buy from a commercial fuel dock because they have a high turnover of fuel and have a maintenance program for changing their filters. I also add Archoil AR6200 every fueling or to any fuel a year old. I run 2 micron primary filters and never have a fuel problem. Because the additive is also a catalyst for better burning, I get a 6-10% mileage boost, too. And I've been buying diesel for my own boats since 1961, I never have fuel issues.

smitty477 said:

"Comments?"

Not nearly enough information for any valued answer.
- What is sooner than previously? Used to last a year+. This time only 7 months.
- How many gallons consumed since last filter? Roughly 170
- How did you know the filter needed changing? Vacuum gauge
- Vacuum reading? Had just reached the red portion.
- Did anyone open the tank and take a look? Not currently possible

Click to expand...

To dhays, mechanic does not offer the service. And I appreciate your responses of adding a biocide and monitoring the filter carefully.

The mechanic thought this was caused by algae. Does that make sense and do biocides kill algae?

Thanks, again.

If your mechanic suspects algae growth in your tank, a shock treatment of Biobor JF or any other diesel biocide should kill it.

When the algae dies, it turns into the black gunk in the Racor which you will need to drain out of the bowl.

In order for algae to grow, the tank has to have water in it. If you have a drain at the lowest part of the fuel tank, drain some out and check for water. If not, you can dip your tank with a stick or run a fish wire or string with a weight to the bottom of the tank via tank fill to test for water with KolorKut water finding paste. Smear the yellow paste on one of the items I listed and get it to the bottom of the tank. If the paste turns red, you have water.

Harlen said:

To dhays, mechanic does not offer the service. And I appreciate your responses of adding a biocide and monitoring the filter carefully.



The mechanic thought this was caused by algae. Does that make sense and do biocides kill algae?

Click to expand...

If the filters were really black, that can be caused by bio growth in the tank. While it is commonly referred to as algae, it isn’t. Algae grows in the presence of sunlight. Instead, bacteria, mold, yeast and other micro-organisms can grow in the fuel if there is water present.

Syjos gives good advice. Use a biocide to kill whatever it is that is growing in the tank and check for water. Keep in mind that what the biocide kills will settle in the bottom of the tank and can be a source of contamination that your filters will pick up.

My understanding is that true fuel polishing is done in a centrifuge to get rid of all contaminants and water. After that the tanks would need to be opened up and cleaned. You may not need that if your filtering system is adequate. Dual filters with a vacuum gauge should allow you to keep tabs on the filter system without running a risk of a catastrophic clogging.

The most important issue to do what you can to make sure there isn’t a lot of water in the tanks and that you take care of any possible water ingress into the tanks. Chances of the water problem being from fuel you have taken on are real, but given where you would normally fuel I don’t think the chances are high. Likely you have already done so, but check to make sure the O-rings in your fuel fills are in good shape.

I polished my fuel in 2009 through inspection ports on my tanks.and cleaned the Racors throughly.

I only purchase ValveTech fuel from high volume dealers once a year. I leave less than 50 gallons in the tank through winter. I have a small circulation pump to run fuel through the Racors which I turn on when I'm working on the boat.

My fuel is drawn from a port in a sump located at the lowest part of the tank. It should pick up any water but have not had water in the Racors bowl.

I test for water monthly via dip stick smeared with KolorKut water finding paste. Never detected water.

5 years after the fuel polishing, the Racors started picking up flecks of black which increased every year. I now drain about 1 inch of black gunk out of my 500.

I don't have water in the tanks.

I plan on opening up the tanks this winter for inspection and if necessary, another polishing.

Where is the black gunk coming from? Beats me, but I've learned not to be overly concerned with it.

"Where is the black gunk coming from?"

Probably ashpaltene , just old fuel clumping as it ages.

Filters catch it easily,

Asphaltene - Wikipedia

https://en.wikipedia.org › wiki › Asphaltene
Asphaltenes are molecular substances that are found in crude oil, along with resins, aromatic hydrocarbons, and saturates (i.e. saturated hydrocarbons such as alkanes). The word "asphaltene" was coined by Boussingault in 1837 when he noticed that the distillation residue of some bitumens had asphalt-like properties.‎Composition · ‎Analysis · ‎Geochemistry

Lepke said:

The black is organisms or their waste.]

Click to expand...

The black deposits are most likely high molecular weight compounds in the fuel, and are not biological. They naturally precipitate out of diesel over time. Read this and search for the section on fuel stability.

Note that there are numerous “commercial websites” that come up when you search for asphaltenes. They are trying to sell you something. Good and properly maintained fuel filters are all you really need. I opened one of my fuel tanks and while I found a few small back deposits, there was no water in the tank and no water in the Racor.

Search for the section in Diesel Stability here:
https://www.chevron.com/-/media/chevron/operations/documents/diesel-fuel-tech-review.pdf

Jim, owner of an ESI fuel polishing system.

Edit: I see that FF has already pointed out the asphaltene issue.

FF, how old does the fuel need to be to get the asphalting to aggregate or precipitate out of solution? Syjos doesn’t sound like he has very old fuel. He buys from high volume dealers, and only leaves 50 gallons in the tank over the winter. It seems to me that he goes through his fuel pretty well.

syjos said:

I only purchase ValveTech fuel from high volume dealers once a year. I leave less than 50 gallons in the tank through winter. I have a small circulation pump to run fuel through the Racors which I turn on when I'm working on the boat.

Click to expand...

Where do you typically buy your fuel? Curious as also in Gig Harbor.

IMO, having a fuel polishing system cannot hurt.
Sort of having insurance. You hope you will never need the insurance but, happy to have it when you need it.

Does it look like:



Could be asphaltine. Treat with this stuff. Does a good job of dispersing the problem

https://www.amazon.com/gp/product/B00G4TWBDA/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Here's an extreme example:

dhays said:

Where do you typically buy your fuel? Curious as also in Gig Harbor.

Click to expand...

Dave,

I moor Sandpiper in Port Orchard though I live in Gig Harbor.

I purchase fuel from any of these two marinas selling ValveTech diesel:

Brownsville Marina has a small storage tank and high volume from the geoduck fleet.

Port Orchard Marina has large tank and high volume from the commuter ferries filling up dailey.

I purchase fuel once a year in the spring. I track fuel prices and when it gets low, I call the two marinas for prices and the level of their fuel. I try to buy fuel the day after delivery so I draw from the top of the storage tank. Since Brownsville and Port Orchard are so close to each other, they track each others prices to stay competitive so the prices are within pennies per gallon of each other.

ValveTech fuel is pretreated with a biocide and other fuel improvers. Marinas selling ValveTech has to follow procedures to insure clean, water free fuel.

ValvTect Marine Premium Diesel contains BioGuard micro-biocide and is formulated to keep the fuel free of bacteria, fungi and algae that plug fuel filters, cause corrosion and can shut the engine down. ValvTect Marine Premium Diesel also contains ValvTect's Diesel Guard Heavy Duty Marine Diesel Additive, which prevents and cleans up injector deposits that cause loss of power and poor fuel economy. Fuel economy tests indicate improved fuel economy up to 13.6%. ValvTect Marine Premium Diesel also contains cetane improver, fuel stabilizer, lubricity improvers and moisture dispersant that prevents wear, prevents sludge and significantly extends the life of fuel filters.

syjos said:

I purchase fuel once a year in the spring. I track fuel prices and when it gets low, I call the two marinas for prices and the level of their fuel. I try to buy fuel the day after delivery so I draw from the top of the storage tank. Since Brownsville and Port Orchard are so close to each other, they track each others prices to stay competitive so the prices are within pennies per gallon of each other.

Click to expand...

I know many of you don't need to purchase but once a year, but I'd strongly advise all to purchase more frequently, at least twice a year. Manage your levels accordingly. If you have two tanks and don't even need one, then clean one and only use the other. Fuel does deteriorate.

BandB said:

I know many of you don't need to purchase but once a year, but I'd strongly advise all to purchase more frequently, at least twice a year. Manage your levels accordingly. If you have two tanks and don't even need one, then clean one and only use the other. Fuel does deteriorate.

Click to expand...

I have two 200 gallon tanks, but since they are on opposite sides of the boat, filling one isn’t an option due to the resulting list. Still, not sure how old is too old for diesel.

As I’ve mentioned, on my sailboat I would fill up once a year most years. that was only 50 gallons however. Now, I usually get fuel 2-3 times a year depending on our usage. However, unless we are going to be taking a longer trip I often will just add enough fuel to get over the full. For simplicity, and less potential for spilling fuel on the deck, I will often transfer most of the fuel to the port tank, then put 100-190 gallons of fuel in the starboard tank then equalize them.

syjos said:

Dave,



I moor Sandpiper in Port Orchard though I live in Gig Harbor.



I purchase fuel from any of these two marinas selling ValveTech diesel:



Brownsville Marina has a small storage tank and high volume from the geoduck fleet.



Port Orchard Marina has large tank and high volume from the commuter ferries filling up dailey.



I purchase fuel once a year in the spring. I track fuel prices and when it gets low, I call the two marinas for prices and the level of their fuel. I try to buy fuel the day after delivery so I draw from the top of the storage tank. Since Brownsville and Port Orchard are so close to each other, they track each others prices to stay competitive so the prices are within pennies per gallon of each other.



ValveTech fuel is pretreated with a biocide and other fuel improvers. Marinas selling ValveTech has to follow procedures to insure clean, water free fuel.

Click to expand...

When given a choice, I prefer to buy ValveTech. Breakwater used to sell ValveTech if I recall before they shut down their fuel dock. I too often forget about Brownsville, despite passing it a lot during the year.

OldDan1943 said:

IMO, having a fuel polishing system cannot hurt.
Sort of having insurance. You hope you will never need the insurance but, happy to have it when you need it.

Click to expand...

Many times, what folks refer to as “polishing” is just a filter in a fuel loop that doesn’t go to the engine. If I recall, your boat has a Cummins that returns a LOT of fuel back to the tank. I’m not sure but I think the fuel pumps in the Cummins QSB engines are pumping 60-90 gph of fuel. I typically only burn 2.0 to 2.5 gph so every time I am running my boat am filtering a lot of fuel.

dhays said:

Many times, what folks refer to as “polishing” is just a filter in a fuel loop that doesn’t go to the engine. If I recall, your boat has a Cummins that returns a LOT of fuel back to the tank. I’m not sure but I think the fuel pumps in the Cummins QSB engines are pumping 60-90 gph of fuel. I typically only burn 2.0 to 2.5 gph so every time I am running my boat am filtering a lot of fuel.

Click to expand...

While I do not disagree with you, it may be better to polish the fuel while tied up. Once one polishes the fuel a couple of times, while tied up, then when underway and stirring up the fuel by wave action, any remaining contaminates will quickly trapped by the final Racor filter reducing need of changing them while underway.

Just my opinion..... days, I do like your logic. It is far less expensive than mine recommendations.

There's fuel polishing and then there's tank scrubbing. If you've got gunk buildup in your tank, then there's really only one method that is 100% and that's scrubbing.

I've had inspection plates installed to allow tank scrubbing and another for a tank repair. It cost me $1K for installing 2 inspection plates in my pair of 125 Gal tanks, a thorough tank scrubbing and fuel polishing 6 years ago.

Here's a thread on it.

http://www.trawlerforum.com/forums/s6/fuel-contamination-racor-filter-help-11228.html

I know on a previous boat my Detroits returned a whole lot of fuel, but my current Lehmans don’t return very much at all. So far in the 4 years we have owned this boat we have not had any dirty fuel, knock on wood...

dhays said:

Many times, what folks refer to as “polishing” is just a filter in a fuel loop that doesn’t go to the engine. If I recall, your boat has a Cummins that returns a LOT of fuel back to the tank. I’m not sure but I think the fuel pumps in the Cummins QSB engines are pumping 60-90 gph of fuel. I typically only burn 2.0 to 2.5 gph so every time I am running my boat am filtering a lot of fuel.

Click to expand...

I have the Yanmar 370 but fuel is also returned to the tank. Thanks for that reminder and I will try to find what my gph is.

I didn't have "black gunk" on the filter, it was just black in color.

Heron said:

Does it look like:

Could be asphaltine. Treat with this stuff. Does a good job of dispersing the problem

Click to expand...

My "polisher" is simply a spare racor with an electric fuel pump. I run it all day and will occasionally pick up a bit of crud or some water. Island Gypsy tank outlets are an inch or so above bottom so there is a certain amount of unusable fuel but I believe it gets sloshed around enough to mix. I use Biobor just because.

If polishing picked up a lot of crud I would stick a borescope down fill tube and look around. If I didn't see shiny metal all around a tank cleaning would be next task.

SoWhat said:

My "polisher" is simply a spare racor with an electric fuel pump. I run it all day and will occasionally pick up a bit of crud or some water. Island Gypsy tank outlets are an inch or so above bottom so there is a certain amount of unusable fuel but I believe it gets sloshed around enough to mix. I use Biobor just because.

If polishing picked up a lot of crud I would stick a borescope down fill tube and look around. If I didn't see shiny metal all around a tank cleaning would be next task.

Click to expand...

That's filtering, not polishing. May do what you need still.

Harlen said:

I have the Yanmar 370 but fuel is also returned to the tank. Thanks for that reminder and I will try to find what my gph is.

Click to expand...

Yes. All marine diesels that I’m aware of (which is few because I’m pretty ignorant) return fuel to the tank. Some like the engines that OldDan and I have, return a LOT of fuel to the tank.

Regardless, the unturned fuel that returns to the tank went through your primary and secondary filters. So over time,you will be filtering your fuel. So unless it is truly bad, it should be fine.

I’m still curious as to how many hours on the Racor filter that seemed black?

dhays said:

Yes. All marine diesels that I’m aware of (which is few because I’m pretty ignorant) return fuel to the tank. Some like the engines that OldDan and I have, return a LOT of fuel to the tank.

Regardless, the unturned fuel that returns to the tank went through your primary and secondary filters. So over time,you will be filtering your fuel. So unless it is truly bad, it should be fine.

I’m still curious as to how many hours on the Racor filter that seemed black?

Click to expand...

If I had a black Racor filter cartridge, I would worry.

I would rather get the water out before it goes through the primary and secondary filter.

BandB said:

I know many of you don't need to purchase but once a year, but I'd strongly advise all to purchase more frequently, at least twice a year. Manage your levels accordingly. If you have two tanks and don't even need one, then clean one and only use the other. Fuel does deteriorate.

Click to expand...

The ValveTech fuel is stabilized for one year. By the time I purchase fuel in the spring, I have less than 10 gallons of fuel in my tank that will get diluted with the new 200 to 250 gallons.

FlyWright said:

There's fuel polishing and then there's tank scrubbing. If you've got gunk buildup in your tank, then there's really only one method that is 100% and that's scrubbing.



Here's a thread on it.

http://www.trawlerforum.com/forums/s6/fuel-contamination-racor-filter-help-11228.html

Click to expand...

I agree 100%

My circulation pump just circulates fuel through the Racors.

When I polish through the tank openings with a wand, I use a high volume gear pump.