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Johnson 1250 GPH Pump Ultima Combo and Johnson float operation, both two wire

Pseudomind Member Posts: 31 ✭✭

I have primarily dealt with "Rule" floats and pumps and I will say this with the "Rule" floats they typically have a switch or lever to test their operation without flooding the bilge.

I have just finished vacuuming about an inch of water in the bottom of my bilge. not high enough to reach the pump as it is on a stainless steel mounting plate.   ( I am use to having and like a DRY BILGE!  I can find no way to test the float.  The pump will run when activated at he helm switch.  So there is not an online fuse issue that I can see.

The bilge pump has two wires a brown and a black and this runs into a cable connection plug which from there runs into a plastic conduit.

The black float assembly has a brown and a black wire with a white stripe which also runs to a connector plug and then into the conduit. NO inline fuse evident

Just how do these Johnson floats operate?  Do they have some type of chemical which dissolves when activated? I would sure like a float I could test.

Is it possible to replace the Johnson float with a "RULE" model so all one has to do it depress a lever or turn a knob to test?  With the 'Rule" when you test the float the pump runs.


2011 Hurricane Sundeck 187 OB

2002 Sea Ray Sundancer 380


  • cjjjdeck
    cjjjdeck Member, Moderator Posts: 1,872 ✭✭✭✭
    Here's the description of the Johnson Ultima Switch built in to your pump out of the Johnson Marine Catalog.  They use a "field effect" sensing technology where the sensor never comes into contact with water:

    Ultima Switch™
    Uses the patented Mirus field effect detector cells producing micro-electrical fields
    that detect disruptions caused by water and fluids. Detector cells are totally sealed
    and are never in contact with the water, will not corrode and are not affected by oil
    or foreign debris. No moving parts, totally sealed solid state electronics and field
    detectors, no mercury and no exposed sensors eliminate corrosion possibilities and
    makes the Ultima switch environmentally sensitive. Ultima activates at a 50 mm (2")
    fluid level and deactivates at a 20 mm (¾") fluid level. A 3 second delay prevents false
    starts. Ultima switch is rated to handle pumps up to 20 amps at 12 or 24 volts.

    Attached is the manual.
    2012 SD237 I/O Mercruiser 5.0L MPI ECT/ Bravo 3
    2012 Load Rite Elite Tandem axle trailer