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08-09-2014, 08:25
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#16
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Registered User
Join Date: May 2008
Location: daytona beach florida
Boat: csy 37
Posts: 2,976
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by d4raffy
I wondered about doing this. Is there no risk to the injector pump / injector system - with the pressure this creates ?
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No problem because it is running at the same pressure that the regular engine mounted mechanical pump is at. And the injection pump itself creates a pressure far in excess of any that an ordinary fuel pump does. One day I had loads of solar power and let it run for five hours. Must have passed the fuel in the 50 gal tank through the racor 3 or 4 times. Then I changed the racor filter.
The electric fuel pump Is a Walbro automotive pump, very high quality and cost me over $100, but I decided the fuel system was no place to save money on a cheap pump.
As goboatingnow says, you still get crud in the bottom of the tank. Fortunately my tank is extremely easy to access, right in the middle of the salon, and has a large cleanout hatch on top of it. And since I jerry jug my fuel I run it through a filter as I pour it in the tank.
Beginning to think I'm getting a bit anal about fuel....
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08-09-2014, 08:42
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#17
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Fuel Polishing System Installation
One thing we intentionally designed into our fuel polishing system, was the ability to draw fuel from the very bottom of the tank at one corner, and return the clean fuel to the opposite side in a way that would wash across the bottom of the tank in order to draw up any crud or water on the tank bottom. Using the original take up and return servicing the engine and generator, were not considered, due to the fact they are elevated a little bit off the bottom to prevent drawing up the crud that turns into sludge.
To date, the tank bottom remains spotless, and several pieces of black crud found resting on the tank bottom when the system was first installed, were gobbled up immediately by the Separ when we first turned it on. So, it does seem to keep the tank bottom clean if properly designed.
Another fuel related precaution we take, is always ending the season with a full tank of diesel, in order to prevent condensation inside the tank during the winter. To date, we have never had a moisture/water accumulation issue. From what I understand, the tank bottom crud loves to grow in the water if it's allowed to stay on the bottom for any length of time.
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08-09-2014, 09:41
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#18
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Registered User
Join Date: Jul 2010
Location: East Tennessee
Boat: 1989 50 ft Roberts
Posts: 859
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Re: Fuel Polishing System Installation
Im in the process of designing/building the polishing system for my project. I have 4 fuel tanks. The polishing system is completly seperate from the engine fuel supply, and it can be used to move fuel between tanks by the turn of a valve too. It seems to me that more than a few of the sailing incidents are fuel related. I want to avoid bad fuel at all costs.
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08-09-2014, 10:20
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#19
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Registered User
Join Date: Oct 2009
Location: Med
Boat: Sunbeam 44
Posts: 112
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Re: Fuel Polishing System Installation
Do you pump it or pull it thru the filter ?
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08-09-2014, 10:39
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#20
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Writing Full-Time Since 2014
Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 9,567
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Re: Fuel Polishing System Installation
It seems to me that water can only enter the tank 3 ways:
1. During the fill. Though many folks suspect this, honestly, it is really rare. It virtually always enters by the...
2. Fill cap (gasket worn). VERY common. Personally, I would pressure test the tank system (plug the vent, let it warm in the morning sun for a few hours, and see if there is pressure when the cap is removed).
3. Though the breather, either from...
a. The sea. Cheach the high loop and make certain this is impossible. There are also traps available.
b. via breathing. And the simplest, most reliable, and most economical way to fight this is a silica gel filter. I've had one for 3 years and it really works (not guessing, tested air in/out with humidity check strips).
c. Knucklehead cleaning the boat. Spray the vent hard and watch.
Dirt seems similar. The fuel pump has a filter on it, so that source is unlikely or at least limited.
There are folks that sell super slow polishing systems. Parker has a very slow pump for this. The problem is, you want to get the dirt and water BEFORE they settle out, since someday you will stir it up. So while slow filtration will make the fuel look really good (filters can be more efficient slow), I suspect it does not solve the problem; risk of stirring the tank up in a blow.
Do bugs need free water? No, I have cultured them in lightly emulsified oil.
Does corrosion need free water? No, even water you cannot see greatly increases the rate (testing).
I think the OP has it about right; do what you can to keep the tank bottom clean, and the rest is handled by additives.
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08-09-2014, 10:39
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#21
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Registered User
Join Date: Jul 2010
Location: East Tennessee
Boat: 1989 50 ft Roberts
Posts: 859
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Re: Fuel Polishing System Installation
Pull, with a vacume guage to monitor the fliters
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08-09-2014, 11:15
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#22
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by d4raffy
Do you pump it or pull it thru the filter ?
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Pulled through on the vacuum side as recommended by Separ and Racor.
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08-09-2014, 11:17
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#23
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by thinwater
It seems to me that water can only enter the tank 3 ways:
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Add #4 which is probably one of the most common ways where we have winter. Condensation due to a partially filled fuel tank.
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08-09-2014, 11:53
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#24
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Writing Full-Time Since 2014
Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 9,567
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by Kenomac
Add #4 which is probably one of the most common ways where we have winter. Condensation due to a partially filled fuel tank.
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That was 3b. Via breathing. Actually, it's worst in the spring, when the tank is cold but the air is warm and moisture laden. My comment was to point out that with a silica gel vent filter, condensation is eliminated and degradation due to air exposure is reduced at least 50% based upon lab and field testing. We've tested this with gasoline and diesel.
Though my boat is gas, I filter both the fuel and the vent.
Sail Delmarva: Gasoline Filtration... and Vent Filtration Too?
The whole thing was written up in Practical Sailor.
(left vented, center sealed, right vent filter. Time, about 3 months)
While there are some that will deny condensation, since empty tanks don't fill, we were able to re-create the effect repeatably. Additionally, underside roof corrosion is such a point of concern in large tank farms that inspectors are required to inspect the the roof structure before tank entry; I've found corroded beams that fell and were on the floor! Condensation, of course, was the cause. Clearly, having fuel in the tank changes the dynamic though the effects of organic vapors, absorption, and precipitation. Complicated, but demonstrable.
The galvanic pairings are aluminum/steel, copper/steel, and brass/steel.
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08-09-2014, 12:12
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#25
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Fuel Polishing System Installation
Thinwater,
Thanks for pointing that out. It never occurred to me that the moisture laden air entered through the vent. Somehow, I thought the moisture came out of the fuel and condensed in the open air space, probably because in the past, I've focused more on stabilizer additives for the fuel. Of course now, the vent tube makes perfect sense.
Anywho... fill the tank, then no air via the vent tube.
Ken
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08-09-2014, 12:13
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#26
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Moderator
Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 18,423
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by thinwater
There are folks that sell super slow polishing systems. Parker has a very slow pump for this. The problem is, you want to get the dirt and water BEFORE they settle out, since someday you will stir it up. So while slow filtration will make the fuel look really good (filters can be more efficient slow), I suspect it does not solve the problem; risk of stirring the tank up in a blow.
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Agreed, this is a fuel tank that I filtered for two years before emptying and looking in side. The crud had the consistency of custard meaning that it didn't easily mix with the fuel and therefore wasn't being drawn into the polisher.
Pete
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09-09-2014, 04:39
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#27
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Marine Service Provider
Join Date: Jan 2007
Location: Maine
Boat: CS-36T - Cupecoy
Posts: 3,197
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Re: Fuel Polishing System Installation
When we installed a new tank I designed it around a fuel polishing system at 1.5X - 2X per hour turnover.
The fuel pick up for the polishing system is at the very dead bottom of the tank at the lowest spot. 1/8" off the bottom to get everything.
I started out with a Carter Rotary Vane pump, had it kicking around, but burned it out. They really are not intended for this type of use. I then switched to a Walbro FRB 22-2 and it purrs along nicely. The system also has a drag needle vacuum gauge so I can see how the filter is performing.
For our system the tank was designed around the fuel polishing so other than paying for a couple of extra NPT bungs to be welded into the tank a filter, a pump, some hose and aluminum fittings, dip tubes and shut off vales was all we needed.
Because I started with a brand new tank it has been amazing to see how clean the polishing system keeps the tank. As of this spring zero growth or discoloration on the tank walls. The polishing system runs when ever the engine does and can also be switched on without the engine being on.
I also added a Racor Lifeguard and then an H2Out filter on the fuel tank vent line. The Lifeguard prevents fuel from getting to the H2Out while still allowing the tank to vent. I am in a longn term test of the H2Out and thus far the beads have not changed color on me. The longevity of the H2Out unit seems excellent.
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09-09-2014, 05:39
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#28
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cruiser
Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
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Re: Fuel Polishing System Installation
Nice!
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09-09-2014, 06:16
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#29
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Writing Full-Time Since 2014
Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 9,567
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by Kenomac
Anywho... fill the tank, then no air via the vent tube.
Ken
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True enough. Before adding the vent filter I always kept 90+% full tanks when possible. Mostly, I still keep them 80+% full.
However, a vent filter also seem to reduce air turnover, even on full tanks, by slowing small convective air currents. Not as good as a nitrogen blanket, but better.
The possible down sides of keeping the tank full:
1. Some folks use the boat so little that means years of fuel storage. Not good.
2. Expense. Specifically, when they do need to do maintenance, it can be a lot to trow away. I'm not sure I agree that this is valid.
A vent filter makes a less than full tank acceptable, though for me, I'd keep it full anyway and use the boat enough to turn the fuel over at least once each year. Some boats have ridiculously large tanks for a sailboat, and there is a price to be paid. Not sayin' lots of fuel might be nice mid-ocean and the wind dies, just sayin' there is a price that makes little sense if you don't cross oceans.
I've always felt that more systems die from disuse than over use.
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09-09-2014, 08:47
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#30
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Registered User
Join Date: Mar 2011
Location: Caribbean
Boat: Oyster 66
Posts: 1,333
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Re: Fuel Polishing System Installation
Quote:
Originally Posted by Pete7
Agreed, this is a fuel tank that I filtered for two years before emptying and looking in side. The crud had the consistency of custard meaning that it didn't easily mix with the fuel and therefore wasn't being drawn into the polisher.
Pete
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A biocide/fungicide will prevent most of that. I use Biobor on new fuel. (Banned in the glorious EU of course!) Get a alcohol free version of this or an equivalent product as alcohol can damage various fuel line components.
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