Fuel polisher in Sail magazine

[Srah 1953]

A recent Sail magazine had an article on installing a fuel polisher which in the article seemed to be essentially an additional pump which ran on a timer through a primary fuel filter, in the example on the existing fuel line.
Is it not the case that a typical fuel pick-up line is set slightly above the bottom of the fuel tank to minimise picking up sludge? so surely the fuel polisher operating when the boat is at rest is unlikely to actually pick up the contaminated fuel?

[noelex 77]

It will still do some good, particularly when the tank is stirred up following a rough sail, but it is better to have a fuel polishing pick up at the bottom of tank. This is what my boat has, thanks to a sensible original owner, who thought carefully, and practically, about all the on-board systems.
Some fuel tanks can be retrofitted with a low level pick up

[AnchorageGuy]

I like to think of these systems as enhanced fuel filtering as opposed to fuel polishing. A true polishing system will have enough pressure from the pump to stir up the tank as the fuel circulates. Any additional filtering will certainly help. Chuck

[noelex 77]

Originally Posted by Waterwayguy

I like to think of these systems as enhanced fuel filtering as opposed to fuel polishing. A true polishing system will have enough pressure from the pump to stir up the tank as the fuel circulates. Any additional filtering will certainly help. Chuck

As you say the two process are different.
Professional fuel polishes use a powerful pump to stir up the tank and ideally move the pickup point around. It is used for a couple of hours as needed perhaps every few years.


Permanent fuel polishing systems typically use a smaller pump, but they are used frequently. Mine is on most days usually for a couple of hours. The lower pressure stirs up the tank less well, but sailing in rough conditions does that better than any pump. The permanent systems filter the fuel many more times because they are on for much longer. They also filter any new fuel or water that gets introduced into the tank.

The actual diesel filtration system used for both systems is very similar.

Overall I think a permanent system has a lot to recommend it and will be superior to a professional system only done occasionally.
Other steps are important ,such as checking the condition of any fuel before you put it into the tank, using a biocide and stopping water.
If your tank is very dirty only draining and physically cleaning it will probably work, but fuel polishing will prevent ( or at least greatly delay) it reaching this state.
There seems to have been an increase in the fuel problems I am noticing, over the last few years, and a permanent fuel polishing system is a great improvement that is often relatively cheap and easy to install.

[webejammin]

Our boat has a fuel polishing system built in as it puts back in the tanks more than it uses after going thru the system and a racor filter. We also remove our fuel tanks yearly and empty the crud and reinstall the tanks it takes about 30 min to do the job if I don't count traveling to where I can poor out the remaining disel in a 5 gal bucket. Our pickup tube does not pickup the last almost 5 gal of disel so letting it settle and poring off the good disel only leaves less than one gal of waste to dispose of. I've only done this once sence we bought our boat one year ago. I usually buy our disel at regular gas stations and don't think I get as much crud that way.

[DeepFrz]

Our boat has a fuel polishing system built in as it puts back in the tanks more than it uses after going thru the system and a racor filter.

That, once again, is not a fuel polishing system.

[FlyingCloud1937]

Hi all, an on-board fuel polishing system can be had by a DIY, for a little bit cheaper then a store bought, but it can be made more effective, for that same less money.

Lloyd

Here is my fuel delivery system.



Here is my polishing system, it is completely independent of the fuel delivery system.

[ATC]

Most 'fuel polishers' ONLY clean the fuel while the real demons sleep at the bottom of the tank awaiting your untimely entrance to a dark harbor at night. There is ABSOLUTELY no equal to tank cleaning.

[AnchorageGuy]

ATC is absolutely correct. You must begin with a clean tank and add the "enhanced filtering system" to keep the fuel clean. If the tanks are dirty then it is putting a band-aid on the problem. Tank cleaning should be an every five year maintenance chore, or sooner if really fouled fuel is pumped on board. Even using a professional service will only go so far if the tanks are dirty or corroded from the inside. Chuck

[Vasco]

Had my fuel polished and tank cleaned in Ft. Lauderdale last January after a fast sail across the stream and back when the engine acted up on the other side. The guy who did it usually goes to marinas and I was on a mooring. He had no AC power for his pumps so I cranked up my Honda and we were in business. Pumped out all my fuel into his tanks, polished that fuel through a few filters, opened my tank and used a high pressure wand to get the crud out, checked the whole tank with a little mirror, put the sender back on (this is the hole we used) and filled the tank with clean fuel. For no surprises this should be done every couple of years.

[s/v Jedi]

A good fuel system starts with the design of the tank(s). What you need is a low point or better, a real sump underneath. Baffles must allow passage of crud and water so that all can accumulate in the sump.

Now you can either make a connection to the bottom of the sump, or from the top of the tank you can install a suction tube that goes all the way down to the bottom of the sump. Do not put a strainer on that suction tube!

My boat was built in the USA where connections underneath are not allowed. Thankfully, Steve Dashew put a plug there, which I could remove to install the connection. A suction tube works too. If either gets clogged, you can blow them through. This would only happen shortly after making this, as the fuel will be clean from that time on.

If you search Google for "Jedi fuel system" you get full info on how to create the ultimate system. I based that design on the system aboard Nordhavn yachts.

cheers,
Nick.