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Water in fuel

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  • Water in fuel

    Hi guys,

    Conversations about water in the fuel have got me wondering...

    I seemed to have picked up a whole lot of water in the fuel over the course of the summer.

    What kind of damage can running fuel in a new carbed 200 merc. do?

    It seems I've been running with a whole lot of water in the tank this summer. We replaced an O-ring at the filler cap which 1/3 missing.

    Regarding the water in the tank the guys at the shop said keep emptying the fuel separator and it'll be fine.

    Is this sage advice?
    1991 Mako 211[br]

  • #2

    Regarding the water in the tank the guys at the shop said keep emptying the fuel separator and it'll be fine.

    That's what I'd do. Just keep a jug or jar, what ever is easiest to empty into on board. Something that you can seal up and dispose of"size2">


    • #3
      Sounds good, but no issues like "scuffing" to worry about running water through?
      1991 Mako 211[br]


      • #4
        smart move...let the boat sit for a while if it all ready isn't than remove the vent hose and pressurize that hose to 3psi-put the feed hose to the engine off and put it in a bucket - put air in the tank and any water you have will be expelled into that bucket- than you have to find the source of water in the fuel. and yes that water in the fuel will cause scuffing it can also cause a detonation-water doesn't belong in a fuel system!!


        • #5
          Guess this is a question to both thrends of "water in the fuel"..

          If you pressurize the tank via the vent, how does that expty the water? I always thought that the water settled on the bottom of the tank. The draw tube does not go down to the the bottom of the tank (right?).. Am i wrong, does fule get pulled from the bottom of the tank? Wouldnt it be best to remove the sender, and pump out the fule form the lowest point of the tank?

          Also, I was told the same advice as brooke- and now i have "scuffing" even though i drained the racore bowl or cahnged the filer evertime i went out.... I think I need to check to oil as noted in the past thrend, and pressure test the tank...

          But, Brooke, be careful, it is very sad to hear that you have scuffing[]
          \'76 Dyer 29- PALMETTO[br]\'?? 17 Angler [br]Darien, CT


          • #6
            the fuel with drawl tube goes to just off the bottom of the tank by pressurizing that tank you will push water out of it due to the fact water is heavier than fuel.this is the easiest way to remove water due to most tanks being made from aluminum-when the sender is removed on older fuel tanks some times the threads that were in that aluminum come out with the screws-than you have quite a problem!! as far as scuffing on pistons water can cause that scuffing condition-i recall you posting that you didn't have water in the filter bowl. i don't remember what make engine you have - but i recall adding to that thread.


            • #7

              You did reply, and thanks. I didnt think I had h20 in fuel but something has to cause this... so i guess i start with checking the fuel, and the oil. Right?
              \'76 Dyer 29- PALMETTO[br]\'?? 17 Angler [br]Darien, CT


              • #8
                Keep one of these in your boat toolbox. No metal - no rust.

                1978 Mako 25 - Blind Hog
                1985 Mako 20c - sold
                Fort Walton Beach, FL


                • #9
                  JAWZ is right. NO water should enter the fuel swystem or cylinders. Major damage imminent. My friends' Sea Mark took water into the motor, no good. Thru the vent tube, filler neck, etc...don't rely on the separator..the Alamo, last bastion of dry fuel, whatever, for sure. NO! Fix the problem.

                  \'73 22 Mako Reedville, VA


                  • #10
                    OK, Water in fuel does more than just cause poor performance. It damages the motor with Scuffing... sorry to be so ignorant, but what is scuffing?

                    I belive I found the location where the water could enter... the 0-ring around the filler cap was broken and about a 3rd of ti was missing.

                    Interesting issues: poor starting, sometimes had to choke it to get it run past 2000 rpm like it was fuel starved. Sound like water in the fuel?

                    Also, what about dry gas? I hear it's not a good thing to use regularly but a one time application?
                    1991 Mako 211[br]