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Mercruiser 300 dies on the water

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  • Mercruiser 300 dies on the water

    Older boat and motor, but new to us, so we don't know the history. Bought it from a dealer, and here in Illinois it would be a fresh water boat.

    Engine starts immediately and runs fine. We've had it on the water three times and each time it quit after an hour. We don't see any common cause or event in the three times. Rough water or smooth water, WOT and slower. Temp guage shows normal range. Each time we got towed as it would NOT restart, but the next day on muffs, it fires right up.

    Hmm. Where do we look. I'm guessing fuel line, but would appeciate all replies as we are new to boating so have no experience. Thanks.

  • #2
    Re: Mercruiser 300 dies on the water

    I would start by verifying that the vent for the fuel tank is clear and allowing air in/out.
    Best regards,
    Formula 330 Sun Sport
    Twin Mercruiser 7.4 LX MPI (0F802036, 0F802039), Bravo 3's (0F806198, 0F806199)
    1969 Mercury 7.5 HP Outboard (26346XX)
    My F-330 Web Site: http://home.comcast.net/~tpenfield/F...30SS/Home.html
    My F-242 Web Site: http://home.comcast.net/~tpenfield/W...Boat_Page.html
    Member of the Month - February 2013


    • #3
      Re: Mercruiser 300 dies on the water

      When it dies, do you still have spark? Do you get fuel out of the accelerator pump holes in the carb if you pump the throttle?
      Don S.


      Please, no PM's (Private Messages) regarding boat/engine problems.
      That is what the forums are for.
      Only forum/moderator issues will be answered in PM's.


      • #4
        Re: Mercruiser 300 dies on the water

        Thank you both for the reply. We'll check the gas line and tank vent here at home next we pull the boat out of the shed, but Don's questions won't get answered until we're in the water if the problem comes back.

        This was just what I was hoping for: a few suggestions to get us started. Thank you!


        • #5
          Re: Mercruiser 300 dies on the water

          You don't need the boat in the water to try don's suggestions...
          '86 Glastron Conroy X-19, Merc 170
          '04 Carolina Skiff J14, 25 hp Mercury


          • #6
            Re: Mercruiser 300 dies on the water

            Turned out to be electrical. Kill switch wire was shorting. End of topic.