Fuel polishing

Discussion in 'Diesel Engines' started by ted655, Feb 28, 2007.

  1. ted655
    Joined: May 2003
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    Location: Butte La Rose, LA.

    ted655 Senior Member

    There may be a thread, if so I missed it, sorry.
    I've bought a diesel powered houseboat. Engine is a Volvo 6 cyl.
    I see a potential problem with the fuel. The previous owners kept it at dockside mostly. The short tours they took on the lake were fueled by 1 or 2 5 gal. cans of diesel added to the mostly empty tanks. . So... 2 large 125 gallon tanks have set mostly emty while the ocassional 5 gal jerry can of diesel has been added from time to time.
    We are bringing the boat to the Ohio river and then on down to louisiana. 800 mile trip.
    According to previous owner, he has always changed the filter/seperator every year and had no problems while taking these short trips around the lake. Me? I only see problems! After I fill up with 250 gallons of fuel, slosh it around a bit and set off down river. I antisipate all hell btraking loose.
    I'm sure I need to polish all that fuel BEFORE it heads for the engine and it's one puny little seperator/filter.
    Question is; what are my options? What will work Without having to buy a expensive $2,000 system? There are many "claims" out there. What REALLY works? I've looked a Gulf Coast Filters. Are paper towel rolls really the way to go?
    I could use help from those who are already polishing their fuel. Thanks.:( :(
  2. Tim B
    Joined: Jan 2003
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    Location: Southern England

    Tim B Senior Member

    I think CLEANING the fuel tanks is the first job. Then you can fill them and use a fuel treatment. I couldn't suggest which one, I do my best to avoid engines and fuel!!

    Tim B.
  3. bilgeboy
    Joined: Dec 2005
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    Location: Boston

    bilgeboy Senior Member

    I’ve got a couple of thoughts for you.

    The first is that you don’t really have any fuel to polish. If there had been 250 gallons sitting around for a few years, you would definitely want to polish it…but you don’t have any. If you did, you could call a polishing service to run your tank of diesel through their system, and it certainly wouldn’t cost $2,000.

    The second is that it isn’t good to have a single filter from the tank to the engine. Are you sure that this is the case? You want a filter/water sep AND an engine mounted filter. I suspect that you do have this set up. You have to at least have an engine mounted filter, and if you can see a water sep as well, you’re in good shape. If not, add a Racor water separator for a few hundred bucks.

    I run 2 micron and 2 micron, and even when I had a water problem in my tank, the microbes were still pretty manageable with a single filter change yearly. Keep a few extra filters handy for your trip and I think you should be in good shape. Sounds like fun.

    Take care,

  4. kenJ
    Joined: Jul 2005
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    Location: Williamsburg, VA

    kenJ Senior Member


    If the tanks are basically empty, just drain the fuel. Clean the tanks, acetone works well. Refill and treat with biocide. You should be fine. I second the idea for a Racor water seperator if you don't all ready have one. The drop in filters are more convenient to change underway, but cost a bit more if you are starting from scratch I would go that way. An small automotive electric pump mounted after the Racor will help restore the prime when you change the filter.
  5. catmando2
    Joined: Sep 2006
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    Location: Australia

    catmando2 Malaysia bound....soon

  6. Frosty

    Frosty Previous Member

    Check your volvo fuel system. Some of them especially the bigger 6 cylinders and above have fuel returns. this is not just a bleed off that old engines have this is a serious amount of fuel returned to the tank.

    This is really a free fuel scrubber--not polisher.

    Get the book out and you will find you are returning maybe 30% of fuel as the engine runs.

    I built a fuel scrubber fom an old auto pilot constant running oil pump.

    Any oil pump that can run contiuous will do.

    You are required by law in America to return to the same tank. This is a bummer because you cant evacuate a full tank. You as an American have to put clean fuel bank into dirty.

    So a constant running pump and some filters and you can make a fuel scrubber.

    2 microns is going a bit over the top in my opinion, especially when fuel sold at the gas station is filtered to 30 microns
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "So a constant running pump and some filters and you can make a fuel scrubber."

    However a scrubber or fuel polishing setup ONLY cleans the fuel.

    So any gunk stuck to the side walls of the tank are still there , waiting for the right combination of tank motion to come loose and plug the filters.

    ONLY mechanical cleaning will clean the TANK .

    There are aftermarket kits to allow you cut a clean out hole and install a removeable cover. About $75 US.

  8. Frosty

    Frosty Previous Member

    Cut a hole in My tank would unfortunately mean the removal of the bathroom on one hull and the galley sole on the other.

    800 liters per side and I can just get to the fuel senders. Peering into this hole and I can see what looks pretty clean walls, just occasional gunk comin into the pre filter.

    If I keep em clean now they shouldnt get any worse.
  9. StianM
    Joined: May 2006
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    Location: Norway

    StianM Senior Member

    Those filters are great. Used them on the engines on a supply vesel I sailed.
    Probartly did not do mutch since it allready had ben filtradet in the MDO separators. We also used to install them at the cousguard patrol boats the shipyard I worked for where building. I tryed to convince my old man to install it in he's boat, but he figured out the original penta filters did a good enough job.
  10. Frosty

    Frosty Previous Member

    A fuel polisher is nothing more than a gunk stopper. The engine pre filter and pump filter would handle it but not for long if it was bad.

    I used a simple constant running pump and a water filter from Woolworths for the main gunk stopper and a 15 micron screw on filter block from the parts shop for after. The screw on gets very little work as the Wollworths job does great.

    Just wash and dry in the sun, or buy new for a dollar or two.

    Once round this and back to the tank of my choice. leave it running for hours.
  11. catmando2
    Joined: Sep 2006
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    Location: Australia

    catmando2 Malaysia bound....soon

    A few of the guy's that have system's like in the link's I supplied have no more gunk problem's.

    Use a filter funnel at re-fuel to check quality............Clean fuel in

    Have fuel cycling through the Racor 500fg...............Clean fuel out

    Goes to engine and excess back to tank..................Clean fuel in

    If checking glass bowl on Racor daily, one would catch any problem's well in advance of it being an issue.

  12. Joel102b
    Joined: May 2007
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    Location: cape cod

    Joel102b New Member

    Fuel Cap Pump out water

    Have a great trip!

    I have done the following on a sailboat. After having the Racor water separator keep filling up having to bleed system several times finally did the following:

    1. Check deck fill cap. The O rings go...then when the tank cools air contracts it actually creates a vacuum and sucks water...rain or in the case of the sailboat splash or sometimes the side rail is buried when boat heels/tips....water comes in settles in the bottom of tank. Water = sludge stuff grows. Replace O ring or get a new cap/fill top.

    2. Pump water out of bottom of tank. Take an outboard motor type bulb hand pump ball attach to a line in middle. Zip tie a straightened coat hanger to tube to keep tube straight....open tank...take out fule lever sending unit or whatever works... stick tube in lowest spot and pump out water....oh...use a clear hose tube to help see stuff go through...pump water and sludge out into gerry can until you reach good fuel. If you can, remove tank and clean or just pump out some water and fuel until clean. Dump bad diesel in home heating system or wherever safe.

    3. Add fuel polishing system if you care to spend the cash and change filters and separator

    New O ring or fill cap will keep water out.

    I believe most water in boat fuel gets in through deck fill cap.

    You are right...in that the water is sometimes OK sitting in the bottom of tank in calm water...take the boat out in rough water shake it up and it then gets into the filters or engine.

    Good luck, Joe L
  13. Frosty

    Frosty Previous Member

    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "800 liters per side and I can just get to the fuel senders."

    Send a "present" that ticks to the boats "designer".

    Has he never BEEN on a boat before drawing this?


  15. Frosty

    Frosty Previous Member

    Seawind cats. Ventura power cat 44 foot. Built in Australia.

    I know I know what can you do.

    Hope nothing goes wrong --thats all.
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