Welcome Guest - Sign Up today
Welcome Guest - Sign Up today

Announcement

Collapse
No announcement yet.

Boat dies at half tank of gas, fuel pump question

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Boat dies at half tank of gas, fuel pump question

    All, having a minor issue with my boat.

    When the boat gets down to about half tank of gas, it stalls and won't start again. It's happened a few times now. I've troubleshot it, and it appears that when this condition is occurring, there is no fuel exitting the pressure side line of the fuel filter. Okay, so either my fuel pump is failing or maybe I have a blockage. And right now I don't think it's a blockage, because if I fill my tank, everything runs fine like there's nothing wrong. See, my tank actually sits above the floor in the very back of my boat, and I think good old physics is on my side pushing fuel into the engine for me.

    So anyway, I'm getting to the point here now - while troubleshooting this problem with my test light on my fuel pump I noticed that the pump is only getting power when I have the ignition switch at "start" (i.e turning the motor over), instead of just "on" (i.e the first click). Do you think this is normal? Is the pump only supposed to operate while I'm turning over the engine?
    1998 Moomba Outback, Indmar Blackhawk 350ci

  • #2
    Re: Boat dies at half tank of gas, fuel pump question

    Oops - I may have put this in the wrong section since this is engine related. Apologies!
    1998 Moomba Outback, Indmar Blackhawk 350ci

    Comment


    • #3
      Re: Boat dies at half tank of gas, fuel pump question

      Almost guarentee it's not the fuel pump, theres's probably something going on with the pick-up tube, it should go to the very bottom of the tank, don't know if yours a rigid piece of pipe or a rubber tube you may need to remove the tank.
      '90 Chaparral 2000SL
      5.8 Cobra
      '67 MFG Westfield Regal
      80hp V-4
      (No private messages)

      Comment


      • #4
        Re: Boat dies at half tank of gas, fuel pump question

        If it happens at half tank every time then check for a cracked pickup tube. I could have a crack or small hole in it right at the half tank area, the pump will pull air easier than it will pull fuel.
        http://www.facebook.com/iloveboating


        2004 Sea Ray 185 Sport, 4.3L,190, Alpha
        1994 GMC 4X4 1500, 5.7L

        Comment


        • #5
          Re: Boat dies at half tank of gas, fuel pump question

          I'm going to see if I can check that right now. If I pull the fuel line off the input to my fuel filter, I shouldn't get any fuel out of it if that's the case (in fact, I should be able to blow back through it).

          In the meantime, does the fuel pump behaviour I mentioned above sound right? Should it only get power when I turn the key to start the engine?
          1998 Moomba Outback, Indmar Blackhawk 350ci

          Comment


          • #6
            Re: Boat dies at half tank of gas, fuel pump question

            I've pulled of the fuel line that runs to my filter. I couldn't blow into the tank because there's probably a check valve (which my dad reminded me about as well). However, I can suck fuel out of that line, which tells me that it probably isn't my pick up tube.
            1998 Moomba Outback, Indmar Blackhawk 350ci

            Comment


            • #7
              Re: Boat dies at half tank of gas, fuel pump question

              Ok, now check the rest of the line to the pump, especially if it is rubber, there has to be something causing it not to pull fuel after half tank and I do not think it is the fuel pump causing this.
              http://www.facebook.com/iloveboating


              2004 Sea Ray 185 Sport, 4.3L,190, Alpha
              1994 GMC 4X4 1500, 5.7L

              Comment


              • #8
                Re: Boat dies at half tank of gas, fuel pump question

                Couldn't the "weight" of the gas in the full tank force the line, then as the tank level drops gas no longer flows? My tank sits above the fuel filter and pump in my boat.

                The only other thing it could be is a completely clogged fuel filter, but then I shouldn't have fuel flow when the tank is full either.
                1998 Moomba Outback, Indmar Blackhawk 350ci

                Comment


                • #9
                  Re: Boat dies at half tank of gas, fuel pump question

                  I suppose that could be happening, maybe you do have a bad fuel pump? maybe try to pump fuel into a container right off the pumps outlet take it off the carburtetor and into a jug, then apply voltage to the pump.
                  '90 Chaparral 2000SL
                  5.8 Cobra
                  '67 MFG Westfield Regal
                  80hp V-4
                  (No private messages)

                  Comment


                  • #10
                    Re: Boat dies at half tank of gas, fuel pump question

                    If it suck's the 1st half, it is not the pump.
                    home is where we drop anchor

                    Comment


                    • #11
                      Re: Boat dies at half tank of gas, fuel pump question

                      Originally posted by rbh View Post
                      If it suck's the 1st half, it is not the pump.
                      My suggestion is that the pump is not sucking at all. Gravity is doing it until the tank level equalizes with the engine. This is a direct drive boat with the tank in the back, above the floor, higher than half the engine.
                      1998 Moomba Outback, Indmar Blackhawk 350ci

                      Comment


                      • #12
                        Re: Boat dies at half tank of gas, fuel pump question

                        Sean, My Alberta neighbour-
                        I do not think that a motor could run very well with just a siphon charge???
                        You might be suckin air at that point.
                        home is where we drop anchor

                        Comment


                        • #13
                          Re: Boat dies at half tank of gas, fuel pump question

                          Could it be a clogged vent? The pump has the power to 1/2 empty the tank but after that there is too much vacuum for it to overcome? Maybe a dumb question.
                          My 16' '75 MFG Restore
                          https://forums.iboats.com/showthread.php?t=448087

                          Comment


                          • #14
                            Re: Boat dies at half tank of gas, fuel pump question

                            Not sure. I can tell you that I was able to pull off the fuel line running into my fuel filter and suck gas out myself, so I doubt that's it.

                            I'll know more tomorrow, but if anyone else has had this, please let me know.

                            I suspect the oil pressure relay switch right now as well, which apparently fires the pump up. I think I need to try putting 12V on the pump to make sure it's actually working. That'll be the next thing I try, I've overlooked it so far.
                            1998 Moomba Outback, Indmar Blackhawk 350ci

                            Comment


                            • #15
                              Sign up today
                              Re: Boat dies at half tank of gas, fuel pump question

                              Maybe the bottom half of the tank is water.
                              When will people learn that impellers require regular
                              replacement and are not drive it till it pukes items?

                              1984 Regal Medallion 195
                              3.8 V-6 with the dreaded
                              OMC Stringer Drive.
                              2003 Avalanche w/Hypertech

                              If it ain't fixable - don't break it!

                              Comment

                              Working...
                              X