Diesel Polishing

[a64pilot]

This explains bio-films far better than I can
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5045575/

[Lepke]

I've been running diesels for about 60 years, I use a good fuel conditioner every fueling and never have fuel problems with my engines. The only issues I've had were with inherited problems with a new-to-me boat. And then a triple dose of fuel conditioner has solved the problem with the filter catching the dead bugs. I've never had to open a tank to solve the problem.

[s/v Jedi]

Using a biocide does not clean your tank. It is a poison and all it does is kill the bacteria and leave them there. This is why you should only use a biocide when you have an actual problem and use an enzyme based system (that does clean the tank, think enzyme based detergent) regularly to prevent problems.

I write regularly, not always, because when you buy a tank of diesel from a 1st world place and use that up in 6 months then you don’t need anything at all. We take 400 gallons and it lasts us 2 years or more (our record is 8 years) and that is where the enzymes start making sense. I would say for fuel that needs to last for more than 6 months. When you get cr@p fuel with methanol, then you need it all the time, but here in Florida on boats you get the real stuff

About water in fuel: we took 375 gallons of diesel in Panama last year. It came with a sealed, certified sample that looked great. After polishing I drained the water from the bowl and that was about 1/2 cup from each tank. Significant amount I think.

What I like about the enzyme treatment: when the transparent bowl of the fuel filter starts looking darker and darker as the fuel ages... then you add Startron, circulate a bit and a couple days later the bowl looks all clean and the fuel looks all light and clean again. You actually see it.

[a64pilot]

I disagree, you use the poison to keep from there being a problem, once you have a problem you have a mess to clean up, so don’t let there be a mess to begin with. The reason Valvtec fuel has a biocide in it as it comes from the pumps is as a preventative.
I’m using the Startron too, based mostly on a PS wrote up saying it helped with fuel tank corrosion. However it seems to also help the Smokey Yanmar issue, so I assume it’s a Cetane booster as well?

Paragraph 5 for the biocide contained in Valvtec fuel
ValvTect - Marine Fuels

[Bill O]

Nick,
Never tried the Star tron products, which one are you using, the enzyme fuel treatment or the enzyme tank cleaner?

[daletournier]

I've had dirty fuel twice, both times in remote places. Been on a remote island empyting my tank and pumping it back in through a 5 micron water filter. Had to fly filters in from Sydney to west Sumatra once as I'd gone through all I had.

I've bought fuel in all sorts of locations, even had it scooped out of a 44 gallon drum with the top cut of and then filtered through a sock while on a beach, sometimes you dont have much choice.

Nothing goes in my tank these days that dosent go through 500 racor (10 micron)and pump I have set up on board. I do this even when it comes from a marina, I always fill from jerry cans, no exception. Vacuum gauges on my engine racors let me know if theres a problem.

Since I've been doing this I havent had any issues. Yes it takes longer but it's worth it for me.

[s/v Jedi]

Originally Posted by a64pilot

I disagree, you use the poison to keep from there being a problem, once you have a problem you have a mess to clean up, so don’t let there be a mess to begin with. The reason Valvtec fuel has a biocide in it as it comes from the pumps is as a preventative.
I’m using the Startron too, based mostly on a PS wrote up saying it helped with fuel tank corrosion. However it seems to also help the Smokey Yanmar issue, so I assume it’s a Cetane booster as well?

Paragraph 5 for the biocide contained in Valvtec fuel
ValvTect - Marine Fuels

It’s normal on this forum to disagree with people, but in this case please explain what a biocide does to help when there are no bacteria yet? Prettysure it is zero effect. Not so for enzyme based like Startron, which keeps working incl. eliminating moisture. This has all been tested and published... in Practical Sailor iirc.

[s/v Jedi]

Originally Posted by Bill O

Nick,
Never tried the Star tron products, which one are you using, the enzyme fuel treatment or the enzyme tank cleaner?

I never heard of the tank cleaner... I use the normal diesel formula product. I would not recommend the tank cleaner because I can’t believe it will do much compared to a cleaning service who run your fuel through a pressure washer that they blast your tank clean with

[s/v Jedi]

Originally Posted by daletournier

I've had dirty fuel twice, both times in remote places. Been on a remote island empyting my tank and pumping it back in through a 5 micron water filter. Had to fly filters in from Sydney to west Sumatra once as I'd gone through all I had.

I've bought fuel in all sorts of locations, even had it scooped out of a 44 gallon drum with the top cut of and then filtered through a sock while on a beach, sometimes you dont have much choice.

Nothing goes in my tank these days that dosent go through 500 racor (10 micron)and pump I have set up on board. I do this even when it comes from a marina, I always fill from jerry cans, no exception. Vacuum gauges on my engine racors let me know if theres a problem.

Since I've been doing this I havent had any issues. Yes it takes longer but it's worth it for me.

With the system that I posted earlier, I can pump and filter fuel from a drum that sits low in the dinghy. I can stick a feed and a return hose into a jerry can and run the engine or genset from that. All things that need to be possible when you sail the places we’ve been.

[Q Xopa]

Originally Posted by noelex 77

A boat installed fuel polishing system will not clean a very dirty tank, but I think it can at least help prevent the tank becoming dirty in the first place.

A boat diesel tank that only needs cleaning out every 20 years is doing well and indicates good fuel practices and probably is indicative of cruising areas where good quality fuel is typical. The interval for full time cruising boats is more commonly 10-15 years and this time seems to be becoming shorter, perhaps due to a combination of more bio diesel and modern engine designs that demand cleaner fuel for reliable performance. Occasionally there are reports of relatively new boats that develop severe tank contamination from presumably taking on fuel with a diesel bug problem where the added biocide was not effective or the resulting dead biomass causes significant problems.

Cleaning the tank is a messy job and unfortunately the current practice of only a small number of access hatches can prevent reaching large areas of the tank. Areas hidden behind baffles cannot be cleaned. This makes it impossible to do a satisfactory job without major surgery.

There have been no controlled studies, but my feeling after talking to many cruising sailors is that a regularly used polishing system combined with other sound fuel practices eliminates or at least greatly increases the time between the need to perform routine tank cleaning and significant improves the chances of controlling a diesel bug problem.

Keep in mind that the ultimate aim is not just to have the cleanest fuel tank, but to keep the engine running reliably in rough offshore conditions when any debris will be stirred up.

We have six large access ports (4 are shown in photo below) for our fuel tanks, which will make cleaning of the tanks relatively straightforward , but I would still rather delay or preferably permanently postpone the task.

Saying "a boat installed fuel Polishing system will NOT clean a very dirty tank". Seems a bit too all encompassing.

Agreed Commercial professional mobile rigs are usually bigger and more effective. However like everything, 'installed systems' come in various capacities.

I have a Racor 900 polishing filter with a Dual 500 Racor filters going to the engine.

I have emulated Jedi, and many of what the Commercial fishing guys do. It works great.

I wont say it could clean any amount. Theres always a limit.

But especially if I regularly, particularly at the start of operation, keep draining the sediment bowl when dirt accumulates. Id say its almost limitless. If its real bad maybe spring for another element when it get clogged. But the element lasts a lot longer if I keep draining the bowl.

These filters are way in excess capacity for my little 75HP Yanmar, so last a long time.

Being in the aviation trade, daily, and every refuel, water drains and checks do a lot to keeping fuel bug (actually a fungi), sediment and water out of your fuel.

I hear discussion of having the fuel pick up at the bottom or a little above. IMHO, the optimal setup is-
Engine delivery from a stand pipe, a little above the bottom,
Fuel test, or poilshing at the lowest point in the tank,
Fuel return aimed at the lowest point in the tank to reduce sediment settling there.

I also agree with Day tanks being great. It gives an extra buffer. Fuel in your Day tank should be squeeky clean and needs nothing else but gravity to keep your engine going for a good amount to get you out of trouble.

As mentioned a Polishing setup is great for filling Filter bowls back up. Also bleeding the engine and checking for leaks. Its much easier to see fuel squirting out than air getting sucked in.

Once you have an elec pump, or even better 2,($60 ea), and a few valves, plumbing and hoses you can do anything- transfer fuel from anywhere to anywhere.

A few examples, sucking fuel from cans in your dinghy then filter it before it goes into the tanks. Filling jerry cans for others. Transferring fuel from one tank to another etc.

Complex, ok a bit, but also very handy and safe.

[Q Xopa]

Originally Posted by s/v Jedi

Using a biocide does not clean your tank. It is a poison and all it does is kill the bacteria and leave them there. This is why you should only use a biocide when you have an actual problem and use an enzyme based system (that does clean the tank, think enzyme based detergent) regularly to prevent problems.

I write regularly, not always, because when you buy a tank of diesel from a 1st world place and use that up in 6 months then you don’t need anything at all. We take 400 gallons and it lasts us 2 years or more (our record is 8 years) and that is where the enzymes start making sense. I would say for fuel that needs to last for more than 6 months. When you get cr@p fuel with methanol, then you need it all the time, but here in Florida on boats you get the real stuff

About water in fuel: we took 375 gallons of diesel in Panama last year. It came with a sealed, certified sample that looked great. After polishing I drained the water from the bowl and that was about 1/2 cup from each tank. Significant amount I think.

What I like about the enzyme treatment: when the transparent bowl of the fuel filter starts looking darker and darker as the fuel ages... then you add Startron, circulate a bit and a couple days later the bowl looks all clean and the fuel looks all light and clean again. You actually see it.

Yes and no.

If you drain as much water from your tanks regularly you will get less diesel bug. Its lives on the interface of water and fuel, so near the bottom of our tanks.

Incidently tank water drains are best done in the mornings after the nightly condensatation cycle has occured.

So to reduce the water to a minimum in your tank you ideally need an outlet/ drain at the lowest point in your tank. This is the ideal pick up for a Polisher filter setup.

Hopefully the majority of your tank water will end up in your Polisher filter drain bowl. So obviously prevention is better than needing to cure it.

But if you do have some bug, best to stem their reproduction rate with a dose of Biobar, (name your poison). This will reduce the overall population and the residule body count that can create mischief in our engines filters.

Another bit of trivia re those dead bodies, apart from clogging our filters, their excreta is acidic and corrosive. This has been known to cause havoc in APC Aluminium fuel tanks corroding them badly, some to the point of leaking. Or anything, particularly aluminium in our fuel tanks.

[mvweebles]

First, OP has a 29 ft boat with a 20 gal tank. I too would be curious to know if this is an ongoing problem or inherited as new-to-him boat. Pump, filters, and valves take a fair amount of space. Hard to imagine this is a good use of space on a 30-foot boat, to filter, at most, 20g of diesel.

Second, there are four possible categories of junk in fuel. Water, bugs, asphaltines, and dirt/contamination. Bugs are less common than most folks imagine. They do not live in diesel but rather at the boundary layer of water and diesel. Eliminate the water and you've gone a long way to eliminating bugs. Biocide will also kill off.

Asphaltines are more or less diesel fuels attempts to revert back to crude oil. As another post suggests, it's a precipitation process and the product of old or low grade fuel. A fuel conditioner works well for this. I've used Stanadyne for years. As Lepke suggests, a triple dose for badly aged fuel will help.

Water. Having drain ports at bottom of tank is great. Racor filters also separate water.

Dirt. With just 20g, fairly easy to manage with a Baja filter.

Bottom line: for OP, polishing system is probably overkill and will consume a lot of space on a small boat. If I absolutely wanted one, would do a portable one that uses the deck fill for access.

Good luck

Peter

[noelex 77]

Originally Posted by Q Xopa

I wont say it could clean any amount. Theres always a limit.

But especially if I regularly, particularly at the start of operation, keep draining the sediment bowl when dirt accumulates. Id say its almost limitless. If its real bad maybe spring for another element when it get clogged. But the element lasts a lot longer if I keep draining the bowl.

Yes, I agree. If you have a very dirty tank I think you are better to open up the tank and physically clean it. If the tank is only slightly dirty, or there is not sufficient access hatches to clean all the baffled areas then a polishing system is worth trying. Better still is to install a polishing system before there is a problem.

Originally Posted by Q Xopa

Once you have an elec pump, or even better 2,($60 ea), and a few valves, plumbing and hoses you can do anything- transfer fuel from anywhere to anywhere.

The cost and complexity of polishing systems is not high. They are a relatively simple and cheap DIY project. As you point out, the system has other uses such as transfering fuel between tanks. The biggest problem is installing a seperate pick-up at the bottom of the tank. If this is difficult. Using the conventional engine pick-up that is usually well above the bottom will still work, just not quite as well.

Originally Posted by Q Xopa

I have a Racor 900 polishing filter with a Dual 500 Racor filters going to the engine.

Our system uses Racor 900 filters throughout. The 900 series have a much greater capacity so if you do have a diesel bug problem it will take longer before the filter clogs enough to stop the engine. By having the same sized filters universally also reduces the number of spares required. However, the 900 filter housings are large so you need plenty of room for this option.


We have three 900 filters. One is 10 micron and only used for polishing or for transferring fuel beteen the two main tanks. A 2 micron filter attached to seperate pump and filter transfers fuel from either of the main tanks to the day tank. This ensures the day tank only has very clean fuel, but there is no danger this fine filter will starve the engine even if it becomes clogged. Generally we also transfer the fuel required into the day tank at anchor when the still conditions help ensure the main tank is not agitated and therefore supplies the cleanest fuel. Polishing is done preferentially at the opposite time when the tank is stirred up when sailing (although the polishing system is also run most days for at least a few hours).

The fuel from the day tank normally gravity feeds the engine via a third last ditch 10 micron filter that guards against the remote possibility of the fuel in day tank becoming dirty. This filter also provides a second means to supply the main engine with fuel directly from the either of the main tanks in the event that the 2 micron filter becomes clogged (although if this occurs then the day tank would continue to supply fuel so the main engine will not unexpectedly stop) or some other problem such as a leak in he system.

This type of system is common on powered long distance cruising boats, but is not often fitted to sailing boats, which is a pity. The cost of components is not high. The resulting system is quite simple, but has a great deal of redundancy and functionality. I would not recommend this for a 29 foot boat, but it is worth at least considering on a larger boat. If refurbishing a vessel adding a day tank can be a way of increaing fuel capacity while utilising a space with poor access.

[daletournier]

Originally Posted by noelex 77

Yes, I agree. If you have a very dirty tank I think you are better to open up the tank and physically clean it. If the tank is only slightly dirty, or there is not sufficient access hatches to clean all the baffled areas then a polishing system is worth trying. Better still is to install a polishing system before there is a problem.



The cost and complexity of polishing systems is not high. They are a relatively simple and cheap DIY project. As you point out, the system has other uses such as transfering fuel between tanks. The biggest problem is installing a seperate pick-up at the bottom of the tank. If this is difficult. Using the conventional engine pick-up that is usually well above the bottom will still work, just not quite as well.



Our system uses Racor 900 filters throughout. The 900 series have a much greater capacity so if you do have a diesel bug problem it will take longer before the filter clogs enough to stop the engine. By having the same sized filters universally also reduces the number of spares required. However, the 900 filter housings are large so you need plenty of room for this option.


We have three 900 filters. One is 10 micron and only used for polishing or for transferring fuel beteen the two main tanks. A 2 micron filter attached to seperate pump and filter transfers fuel from either of the main tanks to the day tank. This ensures the day tank only has very clean fuel, but there is no danger this fine filter will starve the engine even if it becomes clogged. Generally we also transfer the fuel required into the day tank at anchor when the still conditions help ensure the main tank is not agitated and therefore supplies the cleanest fuel. Polishing is done preferentially at the opposite time when the tank is stirred up when sailing (although the polishing system is also run most days for at least a few hours).

The fuel from the day tank normally gravity feeds the engine via a third last ditch 10 micron filter that guards against the remote possibility of the fuel in day tank becoming dirty. This filter also provides a second means to supply the main engine with fuel directly from the either of the main tanks in the event that the 2 micron filter becomes clogged (although if this occurs then the day tank would continue to supply fuel so the main engine will not unexpectedly stop) or some other problem such as a leak in he system.

This type of system is common on powered long distance cruising boats, but is not often fitted to sailing boats, which is a pity. The cost of components is not high. The resulting system is quite simple, but has a great deal of redundancy and functionality. I would not recommend this for a 29 foot boat, but it is worth at least considering on a larger boat. If refurbishing a vessel adding a day tank can be a way of increaing fuel capacity while utilising a space with poor access.

What size is your day tank?

[Pete7]

Originally Posted by s/v Jedi

It’s normal on this forum to disagree with people, but in this case please explain what a biocide does to help when there are no bacteria yet? Prettysure it is zero effect. Not so for enzyme based like Startron, which keeps working incl. eliminating moisture. This has all been tested and published... in Practical Sailor iirc.

Isn't Startron another name, or similar product on a theme, as Soltron? It was pushed hard in the UK during the mid 90s but seems to have fallen out of favour recently. They claimed better mileage too but that is difficult to prove in practise by an owner.

However, your's and Noelex point about not being able to clean a contaminated tank is sadly from experience true. This was a 25 year old tank that I had fuel polished for about 2 years and treated for about 7 years plus likely always filled from UK marinas. The good news is once cleaned it has remained so for the past 5 years. So whatever I am doing is working.

Replace fuel cap seals every couple of years.
Polish fuel a couple of times a year.
Inspect tank every couple of years.
Use biocide every time and vary the type occasionally.


https://www.pbo.co.uk/gear/12-diesel...s-tested-43353

Pete