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Remote Oil Pressure Light

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  • #16
    Originally posted by rodbolt17 View Post
    like Boscoe said. need a full model number.
    not all Yamaha motors worked the same way over the years.
    the old tiller stuff had a green LED that was on when oil pressure was ok.
    later stuff used a red led that was on when stuff was not ok.
    I cannot open the image but I have never seen a key switch with a light.

    but as it is on a blow boat I expect the cheapest rigging imaginable.
    wind is free and everything else outta be.
    Now you have.


    • #17
      Okay. Makes sense. I never looked to see if the new outboards were emitting light under normal operating condtions.

      Sounds like I am back to your original suggestion of installing a diode if I want to be able to remotely sense when the outboard is running.

      Thanks everyone.


      • #18


        • #19
          Picture of Diode


          I am trying to educate myself by Googling things. If I understand correctly, the purpose of the diode is to limit the flow of current in one direction so that the light bulb only gets current from the rectifier/regulator. I am having a hard time picturing how a diode is physically attached to the positive (red) wire between the rectifier/regulator and the 10A fuse. Maybe a picture of the diode in question would help.



          • #20
            Another Idea

            I was down at the boat today and decided to see if any of the "unused" wires from the harness would put out a charge. The dark green wire which is used for the tach puts out about 6V and only when the outboard is running.

            Since I don't have a tach on my boat, I am going to look into getting a 6V LED bulb and see if that will work.


            • #21

              I installed a 6-12V LED using the tach wire in the harness. BOOM! Light only comes on when the engine is running as you might expect. As shown on the starboard side in the photo. I also removed the old oil pressure light and replaced with tilt switches.
              Attached Files


              • #22
                Glad to see you have won.!!


                • #23
                  I have one of these motors, I believe its a 1994-5 model F9.9EXH. The lamp itself is a Neon type lamp similar to the old pilot lights you found on electric ovens. They draw a very small A.C. or D.C. current and on my model I have detected an input voltage of around 60-70V A.C. The voltage to power the lamp comes from the CDI unit and the same wire is connected to the oil pressure switch. The pressure switch should be closed when the motor is not running or should close when the oil pressure drops below a critical level while the engine is running. If the pressure does drop and the switch then closes it earths out the CDI lead which would be how the CDI detects a low oil pressure and subsequently limits the engine revs. When all is good then the other side of the neon light is earthed out and the 65volts or thereabouts coming out of the CDI powers the lamp on.

                  I have investigated how to make the oil light more visible as it is barely lit and impossible to see in daylight. I have thought about using an LED as they can be a lot brighter but the only problem is how to drop the voltage down to just a few volts to run an LED. Perhaps another issue would be the current required to run the LED as neons typically only require tiny currents to function. I think the only solution to this would to have some kind of Voltage Sensitive Relay (VSR) to detect the change in voltage and to control an LED from that.

                  My other thinking is to somehow have a wholly independent system using a separate oil sender unit powered from the key on switch, working on the opposite principle where a light and buzzer would sound should oil pressure be lost.

                  The other principle I guess is that if the oil pressure was to drop, then the the action of the CDI limiting the engine R.P.M. would soon make you aware of the low oil pressure problem.


                  • #24
                    customer calls O halp halp halp I got an alarm.
                    I ask: what Icon was on the tach?
                    customer: I did not look.
                    the latest model tiny mites only light up when oil pressure is lost.
                    it uses a simple on/off switch.
                    can be easily wired to an existing light.