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  1. #1
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    Prime Mercury Optimax 175 question

    I just replaced the float assembly on the VST. It won't fire u. Do I need to prime it?

    Thanks

  2. Banned
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    #2
    It will help you to receive faster, and more accurate responses if you will post your questions in the appropriate forum:

    Mercury Motors (this forum)
    TWO STROKE models (Less than 135 hp).

    Mercury - 2.0/ 2.4/ 2.5 Liter High Performance
    For discussions related to 2.0/ 2.4/ 2.5L Two Stroke motors (Carb, EFI, Optimax or Racing).

    Mercury - 3 Liter & 3 Liter High Performance
    For discussions related to 3L Two Stroke motors (XS, ProXS Optimax, EFI, or Racing)

    Mercury - 4 Stroke / Verado
    For discussions related to ALL Mercury 4 Stroke Engines.

    For fastest/most-accurate assistance, please choose the correct forum.

  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #3
    Moving your thread to the 2.5L Forum. Please be sure to update with the engine serial number.

    Either you've not primed fuel into the VST (via the Primer Bulb), OR there is a float/needle problem (float bent, wrong float level, needle stuck, etc). There are a few other possibilities, but those would be the most common.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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  4. Member Haughton's Avatar
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    #4
    It will take quite a few pumps with the bulb to refill vst when empty. Pump until firm, if it doesn't get firm, needle is not seating, either float out of adjustment or orifice dirty
    1999 ProGator 190V
    200 Mercury EFI 0G843298

  5. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #5
    Or the bulb isn't working properly, or the bulb isn't rotated "arrow pointing upwards", or there's no fuel in the tank... there are several possibilities there.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  6. Member Haughton's Avatar
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    #6
    True. He didn't mention if it would fire up before he replaced float assy.... lol
    1999 ProGator 190V
    200 Mercury EFI 0G843298

  7. Member
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    #7
    Quote Originally Posted by fihon View Post
    I just replaced the float assembly on the VST. It won't fire u. Do I need to prime it?

    Thanks
    yes sir not self primming , bulb must be pumped
    .................................................. ...the scariest thing in life is the unknown ...................................