Installing a fuel polishing system

[Littlechay]

Originally Posted by Kenomac

We polish our fuel weekly and after any fill up.

Weekly!!! Your joking; right? Why?

The must be a waste of energy!

[Salty Mike]

Originally Posted by Martkimwat

I am in the process of adding a proper tank gauge to my stainless steel 60 litre diesel tank , as the sight gauge is hard to read especially below half full. In the process, I intend to add a basic fuel polishing setup comprising a 115 Lph fuel pump which draws just over 1amp and and a Parker Racor 500FG diesel fuel filter water separator. I will use the two spigots of the sight gauge as the outlet and inlet for the polisher setup. My question is, would it be okay to wire the pump through the ignition switch directly, so that when the ignition is turned on, the pump runs and starts polishing the fuel. The ignition panel is for a Yanmar 2GM20 comprising the keyed ignition switch, a start button and four warning lights. Is the ignition switch man enough to carry this continuous load? I also intend to add a bypass switch to be able to switch it on directly without turning on the ignition so that I can run it once a month for an hour in the winter to keep the fuel 'sweet'. I might add I use motor diesel here in UK to avoid red diesel issues with going foreign. my usage is is so little that I don't consider the extra cost to be an issue. The boat is a Parker 27.

I believe you would be better off running the pump off a relay energized from the ignition switch.

[Brooderman]

To answer the question - adding an additional amp of current flow through the switch may or may not matter, but it is a better approach to use a relay to switch the load and the "power on" switch just turns on the power. The idea of a timer to turn it off is also worth repeating - otherwise you may get a dead battery someday... the relay just adds two more wires - there's a reason they exist. And this is the perfect example. There are these mechanical timers you can find at any big box store that will work fine here. They're used for bathroom lights in commercial buildings among other places.

[a64pilot]

lets put this into perspective on the power draw of the pump he is planning.
1 amp is 12 or so Watts, that is the power required to run one interior light bulb or a regular non LED anchor light.
In short, not much, surely an ignition switch could handle a 12 W load continuously?

[noelex 77]

The fuel polishing filter processes 100's many times the volume of fuel that is filtered by the primary filter. We tend to leave ours on whenever we are regulating on solar, although I think it achieves most of the benefit when operated during or shortly after a vigorous sail. It is not unusual for it to be on many hours a day.

The polishing system itself is only a filter (a big filter is desirable) and a small pump, so it need not be expensive. However, the fuel pick up needs to be from the very bottom of the tank. A typical engine pickup is higher than the bottom to avoid sucking up dirt and water so it is much less suitable. Unfortunately, few tanks come installed with a separate pickup at the very bottom.

On our current aluminium yacht we carry 1000 L (250 gal) of diesel, so a polishing system is more helpful for our yacht than most, but I still think it is option worth installing. If you are getting a new boat built make sure it has a pickup at the very bottom of the tank (or sump). Even without a polishing system this will allow you to draw a fuel sample where the water and crud will accumulate.

[a64pilot]

There are two schools of thought on dip tube placement, one is leave it a little above the bottom to keep from getting the dirt etc off of the bottom.
The other is the one that I ascribe to, that is put it at the lowest point there is with the idea of sucking up any dirt or water as soon as it becomes present, don't let it build up.
For those that have dip tubes like mine that screw into a bung welded to the tank, removing, cleaning and replacing is easy, in my case West Marine sells plastic dip tubes with an aluminum 90 at the top that will screw into my existing bung, just cut them to the correct length so that it is just touching the bottom of the tank and your done.
For the generator dip tube, that one you want to leave well off the bottom, you don't want to be able to get stupid and allow yourself to run almost out of fuel from generator usage. I know most of us are smarter than that anyway, right? I did see an RV do just that though, he wasn't smart enough

[noelex 77]

Originally Posted by a64pilot

There are two schools of thought on dip tube placement, one is leave it a little above the bottom to keep from getting the dirt etc off of the bottom.
The other is the one that I ascribe to, that is put it at the lowest point there is with the idea of sucking up any dirt or water as soon as it becomes present, don't let it build up.

Thanks, that is interesting. I thought all diesel pick ups were deliberately above the bottom of the tank.

I think your post illustrates the value of a polishing system. The dirt and crud can be picked up from the bottom of the tank by the polishing system to prevent it accumulating. The polishing system filters many hundred litres of diesel a week so It will be more efficient at preventing the accumulation, than relying on the much smaller quantity from the engine consumption.

The engine pick up can be higher where it should get cleaner fuel.

[Matt Johnson]

Originally Posted by Kenomac

Not right.

2000 gallons of polished fuel used over a three year period and no clogged filters. I did change one Racor and the Separ filter early last season because the filter element was dark, but the vacuum gage didn't indicate a change was necessary.

We polish our fuel weekly and after any fill up.

Man, I thought cats motored a lot

With your part time cruising, that's over a hundred gallons a month. Besides bad fuel, how is anything forming with that turn rate?

Matt

[Davidhoy]

Originally Posted by peter57

...Some engine manufactures recommend not to use biocides...

I have heard this statement before, but have never found an instance where a manufacturer actually states this. Do you have a specific example you can point me to? Not questioning your statement, many others have made it too, just trying to find out if it is one of those Internet anecdotes that has acquired a life of its own, or something we should legitimately take heed of...

Regards,
David.

[a64pilot]

I think it's not uncommon for engine manufacturers to say to not use any additives that are not theirs as there is all kinds of stuff out there, some of it undoubtedly bad for engine components.
But with this new ULSD stuff and possibly letting your fuel sit, if you don't use a Biocide you will eventually have a problem, whether you polish or not.
Old fuel as in before ULSD was I don't think as much an issue, I had until I sold an International 574 farm tractor and a JD 410 Backhoe, fuel in them was over 10 years old, ran fine with no issues when I retired from the Army and started using them again.
Here at work we have a DD powering the fire sprinkler system, tank is a couple of hundred gallons, Lord knows how old it is, I know none has been added since I began to work here in 03, and before that the factory had been shut down for some number of years, likely the fuel is over 20 yrs old.
I've not been there, but rumor has it that at least until recently there was fuel in the South Pacific that had been stockpiled by the US in WWII that was still being used.

[DeepFrz]

For those of you reading this thread and are confused by the yes/no answers of fuel polishing than I suggest you read the linked article by Steve D'Antonio. Steve has a lot of experience in boat management and maintenance and is my guru, although we have never met.

Fuel Polishing Systems Explained | Steve D'Antonio Marine Consulting

Just to add to what others have posted here, polishing also removes water from the fuel tank before it can damage the tank. This also helps prevent the growth of biological creatures.

[rfadler]

I'm in the process of repairing a leaking fuel tank and am going to be adding a fuel polishing system when I install the tank.

One observation that wasn't mentioned in the thread is the placement of the pick-up tube for the fuel polisher. The tank I removed is a 40 gallon tank and I had about 3 gallons of fuel left in the bottom after sucking the fuel out through the pick-up tube. I dumped the remaining 3 gallons of fuel into a bucket and it was a milky consistency. My assumption is that the moisture and contaminants all sink to the bottom of the tank and stay there until your in a patch of rough water with an empty enough tank then it gets sloshed around and picked up by the engine fuel pick-up tube which quickly clogs your engine filters.

I found my tank has a drain plug that I'm going to use as the pick-up source for the fuel polisher. That way I should eliminate the sludge at the bottom of the tank.

[Kenomac]

Originally Posted by Littlechay

Weekly!!! Your joking; right? Why?

The must be a waste of energy!

Not joking, not exaggerating.

Energy is never wasted, we turn on the polisher to increase the load on our 10kw generator which runs 1-2 hours per day in anchorages or when underway if we have the motor running.

[Stu Jackson]

Originally Posted by DeepFrz

For those of you reading this thread and are confused by the yes/no answers of fuel polishing than I suggest you read the linked article by Steve D'Antonio. Steve has a lot of experience in boat management and maintenance and is my guru, although we have never met.

Fuel Polishing Systems Explained | Steve D'Antonio Marine Consulting

Just to add to what others have posted here, polishing also removes water from the fuel tank before it can damage the tank. This also helps prevent the growth of biological creatures.

Steve has written a lot. One of his articles, about bleeding engines, said to "remove the injectors." I found it horrible advice for my engine, which has a separate bleed screw and thus does not need to touch the injectors at all. Sometimes "generalized" advice, while well meaning, is just plain wrong.

In this thread's case, both Ken and a64 make VERY good points, about the "need" vs. "want" of polishing systems. I use a lot of fuel, don't have a polishing system, my boat is 30 years old, I never cleaned the tank, my Racor was last changed a number of years ago at 2613 hours, I now have 3367 hours. I just motored 165 hours up the coast from SF to Vancouver Island. No issues.

Your boat, your choice.

[Kenomac]

Originally Posted by funjohnson

Man, I thought cats motored a lot

With your part time cruising, that's over a hundred gallons a month. Besides bad fuel, how is anything forming with that turn rate?

Matt

More than 65% is used to generate electricity for refrigeration, lighting, cooking etc. This past five month season (2016) less than 100 gallons was used to move the boat and we covered nearly 1800 miles. Less than 350 gallons total used in 2016. We live on the boat full time each year for five months at anchorages.