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Fuel Filtering or Cleaning

Discussion in 'Technical Discussion' started by BONDVOYAGE, Apr 20, 2009.

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  1. BONDVOYAGE

    BONDVOYAGE New Member

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    I have 2 400GL tanks on the Ferretti 55, I have been advised to filter out the fuel and clean the tanks, a $2000.00 process.

    don't mind the cost since it might save me much more in the long run, but the process from what I have been told is to cut out a 10"x10" part of the tanks to get in the hoses to clean the fuel filter it out and put it back.then they cover the tanks with steel plates. The boat is about 10 years old and has never had this done... I hear I will start to dirty my filters up fast if I don't do this???

    I mistake I made was to fill up the tanks when the price of diesel dropped and since the boat has not been used much the fuel has just been sitting in it, but this summer the plan is to use the boat often and take it on long trips. I been told to only put in the amount of fuel I need to use and not keep the tanks full.

    Any experience with this?
  2. AMG

    AMG YF Moderator

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    How does the filters look today when you run the engines? More fuel in the tanks use to mean less water.
  3. Pascal

    Pascal Senior Member

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    if it aint's broken, don't fix it!!

    how old is the fuel, you mentioned filling up when prices started dropping so that would be last fall. If so, it shoudln't be a problem.

    Do have any evidence, symptoms or signs that your fuel is dirty or contaminated?

    you've told a lot of things... :) many claim that it's better to keep the fuel tank full to reduce condensation.

    If you have no symptoms, if your boat doen's thave a history of fuel tank problems and contamination, leave it alone. On the other hand if you get to the point where you have to change the primaries too frequently, then consider polishing.

    instead of spending all that money, if you dont' have them yet, install dual racors.. this way you can swtich on the fly when you see vacuum building up.

    about the polishing process itsefl, it rarely cmpletly cleans the tanks. problem is that you have bafles in the tanks so there is no way to get the return wands behind every baffle and stir the crud at the bottom. yes, it helps and solve most problems but not all.
  4. Opcn

    Opcn Senior Member

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    Diesel oil should not be left to sit for years, it does go bad over time, there are actually types of fungi that can live off of nothing but diesel, but a few months is fine.

    Did someone actually do any type of diagnostic step? Draw some fuel and take a look at it or somehow examine the inside of your fuel tank? If the answer is no, I think it is safe to say that some Marine Mechanic is just trying to make a quick buck.
  5. BONDVOYAGE

    BONDVOYAGE New Member

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    My Maintenance guy has been telling me since the boat is 10 years old its time to do it so I don't get my injectors dirty. the boat has 2 filters for each engine and I can switch from one to the other.

    I changed the filters last summer and they are almost dirty again and I been recommended to change them. but I have been told we should polish the fuel before we change the filters.

    No, I don't think anyone has looked at the fuel, I think the recommendation is coming from the filters being dirty again.
  6. Opcn

    Opcn Senior Member

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    I would consider fuel filter examination a diagnostic step. How much have you run your boat since you changed the filter? If you made one run of a few dozen miles then absolutely that means you have a problem, if you ran all day and night with reckless abandon then your fuel filters being dirty isn't that much of a surprise.
  7. BONDVOYAGE

    BONDVOYAGE New Member

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    Not much we did 2 trips from Marina Del Ray to Catalina, and took it out to sea a few times up the cost to Malibu and back.
  8. Pascal

    Pascal Senior Member

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    well, how do you know the filters are dirty? have you looked at the vac. gauge on the racor? that's really the only way to know the condition of you filter.

    how many hours did you run on one filter before you had to switch to the other one? why did you switch? high vacuum reading? loss of power?

    your injectors are not going to get dirty, that alone let me suspect the mechanic's motive. The filters are going to prevent dirt from getting thru to the injectors, no matter how dirty they are. When they get real dirty then you will experience symptoms like smoke, lack of power, etc... not dirty injectors. At the same time, as they get dirty, vaccum will go up, that's why the vac gauge is important.

    What about the secondaries, have they been replaced?
  9. BONDVOYAGE

    BONDVOYAGE New Member

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    I will have to check my Maintenance records to be sure, I know the secondaries are clean right now...

    I will check my gauges and get back to you guys, I assume my engines have to be on to check this correct?

    this is all great advise, thank you,
  10. NYCAP123

    NYCAP123 Senior Member

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    If I remember the song correctly Catalina is 26 miles of open water each way. That over 100 miles, plus "a few times up the cost to Malibu and back". I'd be surprised if your primaries weren't 'dirty' and am surprised that you secondaries aren't a bit. Sounds like your mechanic is looking for work. Do put in some fuel stabelizer and anti-fungal. Adding a pair of Racors is never a bad idea.
  11. Opcn

    Opcn Senior Member

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    You might enjoy this.

    Attached Files:

  12. BONDVOYAGE

    BONDVOYAGE New Member

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    thanks will do, the Mechanic is not doing the work himself he is telling me to hire the guys who is doing it now sure if there is s kick-back somewhere in the middle of that or not but I am sure there is something.
  13. Capt J

    Capt J Senior Member

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    It is best to keep the tanks full. Algae needs heat, air and condensation in order to grow in diesel fuel. If the tanks are full there is much less air in the tank as well as condensation.

    Do not cut access plates in your tank.

    If your filters have gone through an entire season and are just now dirty, it's not nearly that bad. If you're changing racors every 8 hours thats a different story. If you're going 50hrs between primary filter changes the algae is not that bad, and if you've been in rough seas the sloshing broke free the algae on the walls of the tank. Add a product called "Diesel Kleen" it comes in a grey bottle and will eat the algae.

    Fuel polishing is a complete waste of time and money. Only 90% of the algae is removed. Then if you don't go through that old fuel within weeks and add a good additive, it spreads right back to where you started from in a months time. It will also spread right through new fuel that you've added after polishing just like cancer. Adding a good fuel additive such as Diesel Kleen that eats the algae is your best bet. DO NOT use a biobore like pri-d or the others they will kill the algae and it all will end up in your filters.

    It sounds like you need a more knowledgable mechanic. I wouldn't worry about algae hurting your injectors. Maybe if you had a TERRIBLE algae problem and you're filters were completely clogged and you're pulling 20+ inches of vaccuum it might stress the injector pump or injectors...... Water in the fuel, however will kill injectors.......

    Also you want to check your vaccuum reading while you're at cruise and pulling a normal amount of fuel through the filters. If you see 15lbs or so, change the primaries.
  14. C4ENG

    C4ENG Senior Member

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    I have learned from trial and error, if your tanks are dirty, the only thing that can be done to correct the situation is to have your tanks manualy cleaned. Seperating fuel is more of a maintenance thing to keep the water out. Adding biocide to a dirty tank makes more of a mess of an already messy situation (it breaks it all up).
    If you don't clean your tanks, you will be changing your filters on a hot engine in rough sea's.. as that is when it gets all stirred up and specially formulated to ruin your day, or night at 2 AM as that is when alarms always seem to want to sound!
  15. BONDVOYAGE

    BONDVOYAGE New Member

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    here is a picture of my port side engine with the filters on the lower right, not a very good picture but I need to check and find the gauges

    Attached Files:

  16. NYCAP123

    NYCAP123 Senior Member

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    You have got Racors. You would do well to change the T-bar for a guage. RU finding much gunk in the bottom of the Racors?
  17. Pascal

    Pascal Senior Member

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    actually on dual racors, the gauges are on the cross pipe next to the valve, between the filters, NOT where the T bar fits. the gauge might be just beyond the edge of the pic.
  18. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Might pay to know...

    ...what size filter elements are in the Racors--20 micron? 10? 2?
  19. Mark I

    Mark I Member

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    One point not mentioned.

    It is hard to know how fresh or clean the diesel is from the fuel dock. You can guess that a busy fuel dock turns stock over faster but there is no way to know for sure.

    Therefore, you could go through the entire process and get bad fuel pumped back in the next time you fuel up.
  20. BONDVOYAGE

    BONDVOYAGE New Member

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    These are all great questions and since I am a rookie at this I don't know.. I plan on spending some time down in the engine room taking some detailed pictures and finding out what I have and don't have.

    I try to fuel at long beach since its more cost effective and they turn over fuel much faster than the Marina