dirty fuel from filters

[Wxx3]

Yesterday, I changed both my racor fuel filters for the main engine. Even though the fuel I could see (in the bowl) looked fine, my engine had stopped a few days earlier for no apparent reason.

Once the drain bolt was undone, a flow of the blackest, muddiest looking ??fuel/water came out. It drained at least half before clean fuel started draining. (this was from the filter that was in use when the engine stopped). The second filter was actually worse.

Both these Racors had that stupid vacuum gauge on top, which clearly may work sometimes, but not always. Both gauges where well in the green.

So at this point my drain bucket (normal 2.5 gal bucket) had about 2 inches of the black fuel/water. Once I was done rinsing both filters with kerosene, I had about 5 inches of muddy fuel/water.

I set it aside, wanting to see how it separated.

That's the crux of my question. After sitting more than two hours, it never separated. It Visibility was still not more that 1/8 of an inch. It looked as if it was a very dark solution, with clearly fine particle in suspension, but not settling out.

This is my first experience changing the filters on this boat. i had expected some water and dirt (mud) to separate, with relatively clean fuel on the top. there was NONE.

Is this normal?
Should I do anything to the tanks before i refill them?
How often should I change racor filters?

FYI I have just installed a Racor fuel polishing system. But have only used it sparingly.

Comments?
Thoughts?

Richard

 

[Chrisjs]

Did the engine stop because of water passing the filter and getting to the engine, or because the filter plugged and no fuel could get through? In my experience, the pressure gauges work fine to indicate the degree of filter blockage by particulates. The particles usually appear as granular black sediment when I clean the bowl. Would never expect to see any "mud". Never had a water problem. It sounds as though you have some pretty dirty/wet fuel. Might be worth running it all through the polisher, assuming your polisher is not also based on Racors. Ou polisher is based on a large prefilter cartridge that has high dirt handling capability and can soak up a decent amount of water as well. The Racors are for "fine filtration" at the micron level and will plug quickly if overloaded. If your polisher is Racor based you are probably wasting your time. May need to drain all fuel from tanks and have it cleaned off the boat. When I once needed to separate dirty water/fuel after a bilge spill, it was easy to separate the two liquids and the diesel was fine for use after filtering through paper towels. You might try passing your dirty fuel/water through a paper towel filter to see what it looks like afterwards.

 

[Larry M]

...Should I do anything to the tanks before i refill them?...

Short version: Before you do anything like add fuel, clean the tanks. You should have 2 inspection ports at the front/low end of each tank. If in doubt, hire a pro to do the tank cleaning. You have a problem that has an easy fix.

 

[Wxx3]

Thanks.
I know the inspection ports. Cleaning entails just what...?

I have no problem with the response "if you have to ask, ou should have someone else do it"

 

[Steve]

Do you know how many hours are on the filters? You do know the vacuum gauge reading must made be with the engine running, best at cruising speed. I am asking because you mention it is the first time for changing the filters. You might want to change the engine mounted fuel filter too, cut it open and see how much crud is in it, if any. I change Racors @ 200 hrs
If it were me I'd do a filter change and see how it goes for the next outing or two, there maybe nothing wrong.

 

[Wxx3]

Chrisjs,

It sounded like fuel starvation to me.
Also, I'm thinking the the PO, who used the boat very little in 7 years, was always using one tank and then I started using the other. I probably ran 200 gal thru it.

What surprised me was that looking at the racors, I saw no indication that they were getting so clogged. I'm pleased that they kept the engine running and when I switched filters the engine restarted.

Also, the black particles stayed in suspension longer than i would have thought and saw no signs of water fuel separation.

 

[Wxx3]

Steve,
Just saw your post. Yes, I had about 200 hours on the one filter. Strangely, the dirtier one, I had never used.

As Larry suggested, i will open the inspection ports and see what i see.

 

[Tom.B]

Thanks.
I know the inspection ports. Cleaning entails just what...?

I have no problem with the response "if you have to ask, ou should have someone else do it"

Here is what happen when I did it:

http://www.trawlerforum.com/forums/s31/skinny-dippins-tank-cleaning-trip-report-6551.html

Hope it helps.

 

[Chrisjs]

I would put new Racors in and run it again. See what happens with fresh filters before you get into more involved procedures. We run 2 micron Racors and typically get 50-75 hours before they go into the red zone on the pressure gauge. If you run 5 micron filters you will get more time between changes. You should check the water every several hours and drain water from bottom of Racors to keep an eye on what is really happening. Time between filter changes also depends on how much fuel your engine draws. Some engines have a larger fuel return (to the fuel tank) , so end up filtering more fuel per hour. Just have some spare filters available.

 

[Wxx3]

Thanks Tom et al,

Just the information and detail I needed.

I will check out tank cleaners here in NY, bc clearly it's something that must be done sooner rather than later.

Richard

 

[FF]

Tank cleaning requires ALL the fuel to be removed , the clean outs to be opened and the parts of the tank sides and bottom scraped clean with a spatula.

All the gunk is removed and the tank inside shows clean as you can everywhere..

Then the old fuel is filtered with 2 micron filters and returned or if real ugly given to a home owner to burn in a furnace as heating oil.

From there on new fuel should be run thru a Baja style pre filter before being let in the tank.
A dose of bug killer should be added to each fill up.

Each fillup should be to as empty as you dare run the tank.

Nicest is a day tank with fuel tanks filling the day tank. Then running any of the tanks to empty is no problem .

Some engines do not return much fuel so the Raycore gauge is never accurate.

A gauge that reads the pressure drop across the filter from Murphy , with an alarm if you wish is OTS.

 

[Tom.B]

I was gunking up filters a lot before my cleaning, BUT as you can see in my case, the walls didn't have any gunk on them. It was all in the bottom inch of the tank. Any proper tank cleaner will have the ability to pull, store, and scrub the fuel left in your tank, but it's best that you go into the procedure with your tanks already nearly empty. Then, expect to throw that fuel away and buy fresh. Also, the best way to keep your tanks clean is to only fill up with as much fuel as you plan to use in 3-4 months. Additives are never a good idea unless you already know what has been added upstream of you.

I would certainly find someone that can dip your tanks or do a visual inspection of them before you go into a full cleaning. You could get lucky as we did and have it be pretty painless.

Good luck and keep us posted.

 

[FF]

The best way to keep tanks clean is to have NO WATER mixed in with the fuel.

Unless the tank has a sump , where the water can be lifted often , the fact that fuel contains water when you buy it , and possible condensation in the tank means the food for bugs is always present.So crud will build depending on the water content.

Poisoning the bugs is not an additive , it is insurance for a poorly designed/built cheap tank.

 

[Wxx3]

All good advice.

Was thinking of using an additive, this just confirms that.
Would love to have a day tank, maybe next year.

Will definitely have tank cleaner come look and clean. Pretty much the only thing that can stop a Lehman is a fuel problem, so it's more money well spent.

Tanks, I'll keep you updated.

Richard

 

[River Cruiser]

I saw no mention of draining the water & sludge that accumulates in the bowl, I drain mine every 25 - 30 hours, once in a long while I'll get a little water or sludge. Doing this helps extend the useful life of the filter, also don't overlook the o'ring seal on the deck fill this could be a source of water entering the tank either while washing the boat or during the rain. Good luck

 

[markpierce]

Where's the "green"?

When I can't achieve full throttle due to inadequate fuel-flow (happened once in the two years I've owned the boat), I shift to the other filter and replace the used-up one.

 

[Wxx3]

Where's the "green"?

When I can't achieve full throttle due to inadequate fuel-flow (happened once in the two years I've owned the boat), I shift to the other filter and replace the used-up one.

I don't understand what you mean.

 

[markpierce]

I don't understand what you mean.

Rotating the "Racor" handle 180 degrees shifts fuel flow from one filter to the other. Thus, the unused filter can be changed while underway.

 

[Wxx3]

Rotating the "Racor" handle 180 degrees shifts fuel flow from one filter to the other. Thus, the unused filter can be changed while underway.

I meant I didn't understand the comment, "Where's the "green"?

 

[Steve]

Green "safe zone" on vacuum gauge face maybe?

 

[Gulf Comanche]

Speaking of vacuum gauges, what is a bad reading and what is acceptable? Mine read "9" last Saturday.

 

[markpierce]

Green "safe zone" on vacuum gauge face maybe?

Yes. An earlier poster referred to a green zone. My Racor gauge doesn't have one.

 

[jleonard]

Speaking of vacuum gauges, what is a bad reading and what is acceptable? Mine read "9" last Saturday.

The "green" is usually at 10 in hg. At "9" it's about time to change elements.

 

[Gulf Comanche]

Thanks Jleonard, will do this weekend. Here is a good explanation on vacuum gauges and fuel filters:
The Vacuum Gauge Tool - Professional BoatBuilder Magazine

 

[Wxx3]

Thanks guys,

I am still in the process of resolving this problem.
I have so far not been successful in finding someone who whats to clean tanks for me.

It will probably come done to me, opening inspection port, mopping up any muck on bottom of tank and then polish it forever.

I'll let you know the results.

 

[Wxx3]

Also, really appreciate link to Steve D'Antonio article. He is so prolific adn really like his writing.

Richard

 

[jleonard]

And I think all boats/fuel systems have their own threshold as well.
My "ex" an old 34 Mainship with a 6BTA Cummins would start to lose a little rpm at the upper end of the range when the guage read about 8 or 9. So there was plenty of warning.
My current Albin with the 120 Lehman does not like to run over about 7 and it will give almost no warning of a problem.
Plus depending on your filter system (don't want to get this going) the vacuum reading can change rapidly or slowly.

 

[RickB]

Also, really appreciate link to Steve D'Antonio article. He is so prolific adn really like his writing.

The only problem is, the guy is about a mile wide and an inch deep.

"the fuel supplying the filters will be under pressure and the gauge may indicate this. While this is not harmful and while Racor turbine series filters can work under as much as 15 psi (0.1 N/mm²) pressure, the manufacturer recommends vacuum or suction applications."

That is because any pump will generally produce a homogenized mixture of fuel and water that is all but impossible to remove by the filter element or Racor's "turbine" device.

The same rule applies to bilge filtration or oily water separators, placing them on the suction side keeps the water(and oil) in large and easily removed "gulps" rather than microscopic droplets.


"If the primary filter is placed under pressure—either because of its location and the fuel-tank plumbing arrangement, or because a priming or auxiliary fuel pump is placed between the filter and the tank and it’s operated continuously rather than simply for priming—the vacuum gauge may give no indication of filter clogging. The reason is because the vacuum is being offset by the fuel pressure, creating an equilibrium of sorts. This scenario may exist until enough debris accumulates within the filter element, increasing the vacuum and leading to rapid fuel starvation. To avoid that, tell your customers not to pressurize the primary filter, particularly with an electric pump, while under way."

That is nonsense. A vacuum gauge on the outlet will most certainly show a vacuum when the filter has become clogged. The reading on a compound gauge will change from a positive pressure to zero then to an increasing vacuum as the filter flow reduces. As far as the engine's lift pump is concerned there is absolutely no difference after the suction head changes from positive to negative.

If the guy had as much time in the engine room of an operating vessel as he has at the keyboard he might understand how this stuff works and serve his clients a bit better.

 

[sunchaser]

Steve D's trying to cover a lot bases with his fuel system blanket statements. He gets paid by the word and number of shows he attends.

As is so oft mentioned on this and other threads - old, little used and/or otherwise neglected fuel and tanks may need a good laborious cleaning and fuel system analysis. One boat's problem may be very different on another. Tom's Skinny Dippin fuel system threads are very good but only specific for his case. For the uninitiated, boatdiesel's fuel system and filtering articles are worth a read.

The classic is the guy who wondered why his new boat's engines were surging when his tanks got low in sloppy seas. Someone had the temerity to ask how low and he said about 1/4 or less. Problem - bad fuel gauge and ignoring the site tubes. His tanks were nearly empty and sucking air. Each case is different.

 

[Wxx3]

Thanks Rick B.from another Rick B.
I appreciate your perspective.

I'm going to spend a day polishing and see what I get.