fuel polishing

What is an "inline polisher?"

You can't really have too much water. If there is a whole bunch, clean fuel floats on top and is easily removed or the water drained off from beneath.

If it is an emulsion there are chemicals that "break" the emulsion. If it is just a bunch of water drops suspended in the fuel by shaking or something then a centrifuge will remove it in short order. Another option is a "water block" filter.

I don't understand why there was too much water to have the fuel polished. The fuel polisher's filters should seperate any water and allow it to be drained while it's being polished. You could do this by running the engines at idle and draining your fuel water seperators as they seperate it. Fuel floats above water and you'll pick up most of it at the dock just by running the engines and draining your racors.

The inline fuel filter/polishers can work to remove algae and water. Basically they're nothing more than a racor (or separ) that filters the fuel to whatever filter you have in it (usually 2 microns). I prefer the ones that use the racor filters due to the much cheaper and easier to change racor 1000 filters. You would have to manually keep draining the racor bowl as water accumulates in it. It then has a pump that just keeps circulating the fuel from the tank through the filter and returning it to the tank on a timer. If there's water in the fuel the only way you're going to get it out is by seperating from the fuel, there really isn't any fuel additive that's going to make it go away.

Of course there are centrifuges, but that's a whole different ball game and not something you're generally going to install on a 42' picnic boat.

If you mean an inline polisher like the algae-x type deals. My personal thoughts are that they're worthless. They're installed on 1 boat I run and all they do is macerate the algae into smaller particles and it bypasses the easier to change primary fuel filters and plugs up the secondary fuel filters.....which are harder to change and more expensive.

I'm guessing you are talking about an Algae - X magnetic "filter". Which are pure snake oil IMO. If a relatively weak magnetic field could break apart the cell walls of algae, think what an MRI machine would do to people.

The only independent test I have even seen on them showed they did not work as advertized.

I would suggest perhaps adding a second filter that your owner could switch to if this happens in the future when he is away from the dock so he/she hopefully could at least get home or to a near by dock before the engines shut down. I would also suggest adding the water probes and alarms to the Racors he/she has now installed.

I too don't understand the comment about to much water in the fuel to polish it. Unless you mean there was so much more water than fuel in the tank that it just wasn't worth filtering out the fuel.

A true story about fuel "polishing".

A friend's elderly father had an old wooden fishing boat with a single cylinder 'thump, thump' diesel engine in it. He had been using it for 40 years just do some crab potting and such.

One day the engine wouldn't start, so he called his son down to look at it for him. He went to his father's boat and checked the fuel filter. Yep, full of green, stringy sludge. He checked the fuel tank and in his words "the diesel was so thick, you could have walked across it".

So he went to work on pumping out the fuel into jerrycans and to thoroughly clean the system top to bottom. After steam cleaning the tank out and reinstalling it, he left the tank open to dry out.

He went back the next day to find the lid fixed back on and the tank full. He phoned his father to find out if he had done it correctly, he said yes it had been dry and had been sealed down properly. As he was leaving he went to the boatshed to pick up the jerrycans of filthy old fuel to take to the recycle unit. The cans were there but now empty.

He calls his father back.

"Dad, where's the old fuel"?

"I put it back in the tank".

"WHAT??? It was disgusting. Why didn't you get rid of it"?

"At these prices, you must be joking! Anyway, I cleaned it when I poured it back in".

"Cleaned it? How?"

"Oh, the normal way. I strained it through a pair of your mother's old nylons..................................."!!!


So, it started all over again.