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  1. #1
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    2004 150EFI fuel pump

    2004 Mercury 150 EFI
    serial: OT817589

    So last time I went fishing 2 weeks ago my 2004 Mercury would stall upon putting it into gear. This happened first thing in the morning about 4-5 times. Afterwards it was good. Fast forward to today, it will not start up. It will crank but not start. I removed the VST and took the high pressure fuel pump out, hooked it to 12v and nothing. Doesn’t even attempt to spin. Is there anything else I should look into? These darn fuel pumps are $360-$400 online. Anyone know of a cheaper way? Thank you!
    Last edited by MercRanger185vs; 07-02-2019 at 07:43 AM.

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    No substitute for the right, OEM part. Especially when it comes to Fuel System Components.

    If it does not function with 12V power and ground applied, it HAS failed.


    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

  3. Member
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    #3
    Quote Originally Posted by EuropeanAM View Post
    No substitute for the right, OEM part. Especially when it comes to Fuel System Components.

    If it does not function with 12V power and ground applied, it HAS failed.
    I tested it by hooking pos to pos and neg to neg. It’s my first time testing a fuel pump, is there another way?

  4. Member
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    #4
    replace it /please use merc product not aftermarket
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member
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    #5
    The pump I pulled from the motor was a Walbro GSS436. It was an aftermarket pump. No wonder it failed.

  6. Member
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    #6
    agree
    .................................................. ...the scariest thing in life is the unknown ...................................

  7. Member
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    #7
    So i got the new fuel pump, cleaned out the VST, and reassembled the tank. Primed the bulb until firm. Cranked it over and it sputtered and wouldn't start. It then didn't sputter at all and just cranked like before. The fuel pump is 100% kicking on. I hear it upon turning the key. My guess is the plugs got fouled due to build up of oil from repeated cranking when the fuel pump was toast? I bought new plugs but not sure the next step. Should I just install the new plugs and crank it again or is there a different route?

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    Did you confirm FUEL PRESSURE? If so, what is the pressure at key-on?


    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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    #9
    Quote Originally Posted by EuropeanAM View Post
    Did you confirm FUEL PRESSURE? If so, what is the pressure at key-on?
    so, I took apart the VST again and somehow the float was stuck up when I reassembled it the first time. I reassembled it and primed it, cranked right up! Good to go!

  10. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #10


    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