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  1. #1
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    High press pump (VST) screen at bottom of pump filled with powder.

    1997 Merc 250 EFI (twin). I know I need the serial # but dont have at this moment.

    When I replaced my high pressure pumps (in VST) I found a build up of powder type material at the high press pump screen(s/twins). It seems the Racor water/gas separator is 10 micron and the merc mounted screw on fuel filter is also 10 micron.

    Question: I am debating the logic of using the 2 micron Racor gas/water separators to ensure the high pressure pump screens do not clog up.

    I assume the down side to this is the 2 micron racors will clog sooner but that seems to be a small price to pay to ensure all filters/lines etc are as clean as possible.

    2 micron Racors =good idea/bad idea?

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    2 micron Racors: Bad idea.

    2@ 10 micron filters: Bad idea. Your engine is already equipped with an adequate level of filtration- running additional filters will result in fuel system restrictions.

    The powder you found did not come from the tank as "powder". It is the byproduct of fuel sitting in the VST for long periods of non-use (more specifically, ascorbic acid that attacks the aluminum and other metals in the VST, resulting in a white powder coating).


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  3. Member
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    #3
    EuropeanAM thanks for the info and detailed answer. Great info!