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Dumb bilge pump wiring question

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  • Dumb bilge pump wiring question

    As I went through systems yesterday, it appeared that there was some issue with the bilge pump and float. This morning, I removed both and have been trying to make sense of what I'm finding.

    Boat is a 230 and the switch at the helm is either manual or automatic. Brown wire goes from helm to the bilge in rear.

    There is a rule float switch which is wired directly to the battery and then connects with the brown wire from the helm. This then goes to the brown wire on the pump. I have cut all the wires as it appeared that the issue was with the float switch, and I now have a new one.

    Here is the fun.

    When directly connected to the battery, the pump runs fine. When it connects to the brown wire from the helm, it does not run.

    Moving the switch at the helm to Manual gets the light by the switch to come on, there is 12 volts behind the switch on the brown wire as measured by a multi-meter. At the bilge, there is also 12 volts coming through the brown wire.

    However the pump will not run. In fact, when I have the multi-meter connected and then connect the pump, the voltage goes to zero but pump does not come on. Remove the pump and the voltage goes back to 12.

    In both scenarios, I'm using the same ground as when connecting directly to the battery as well. Obviously running directly to the battery shows 12 volts too.

    I'm getting the feeling that I'm overlooking something really obvious, but it escapes me.

    The fuse at the helm checked out ok too.
    1990 Mako 230[br]1999 Mercury 225 EFI[br]2004 Lund Alaskan 1600[br]2005 Mercury Bigfoot 25[br]Wrentham MA[br]

  • #2
    Im having a similar problem bilge pump runs on manual but not working off of the float I usually shut batteries off after using the boat and the automatic float would work,I dont see a power wire running to the bilge from the battery only a brown wire going to the helm, I did change to a blue seas battery switch last season and cant remember having this problem last year what should I be looking for that I am missing


    • #3
      Just because you have 12 volts on a meter does not mean that there are any amps behind that 12 volts. Had some problem in the past with my old Mako..was a bad wire. Had 12 volts but not enough current to run the pump. Have also had a bad pump when new wire connection did not fix problem. When in doubt with an old boat, run new wires. Your float switch hot wire should come right from the battery..then there is no chance that it got turned off or not turned on. I use the rule matic fully automatic float switches to hang up plug you don't need 3 inches of water to turn the pump on.
      Chris Miller[br]Mystic Islands, NJ[br]1974 17 Classic[br]1988 211 Classic (sold)[br]1990 Grady White 230 Gulfstream (sold)[br][img][br]


      • #4
        Thanks Chris,

        That was the clue I needed. It turned out that the culprit was the power lead from the battery to the helm switch. Replaced that and the circuit works normally again.

        Appreciate the help!

        @ steve, you should have a wire going from the battery to the float switch, then from the float switch, the wire should connect with the brown wire from helm and the brown wire from the bilge pump itself. That will allow it to work with auto mode with power off at the battery switch and with manual mode.
        1990 Mako 230[br]1999 Mercury 225 EFI[br]2004 Lund Alaskan 1600[br]2005 Mercury Bigfoot 25[br]Wrentham MA[br]


        • #5
          Just an idea on bilge pump wiring, something I had read online once and did on my boat:

          After I had changed out my pump and or float switch several times, I decided to make it easier, and possibly better:

          I mounted a terminal strip as high as possible in the bilge, but within three feet of the pump location. The terminal strip is wired back to the helm switch and the battery for both ground and 12v. (can isolate parts of the strip for + and -)

          Now it is a simple matter of crimping on ring terminals to the pump or float's OEM wires and put it on the appropriate lug of the terminal strip.

          no more wire connectors that could possibly leak laying low in the bilge, and easier to trouble shoot with voltmeter.

          Sorry, would add pics, but not near boat.
          [br]DonK[br]Boca Raton, FL[br]1979 236IB: \'The Fish Tank\'[br]1979 Backcountry 18 \'Boner\'[br]<>< <>< <>< <>< ><> J[br]Redneck Troubleshooting:[br]1) If it moves, but ain\'t supposed to, use Duct Tape[br]2) If it don\'t move, but supposed to, use WD40[br]3) If that don\'t fix it, it\'s electrical![br]