Fuel gauge drives to zero with ignition switch on
Posted: Tue Aug 07, 2018 1:09 am
1987 Mercury 150hp, two-stroke-cycle motor.
Previously, I had the fuel gauge and sender system wired to the Perko battery master switch. So when I turned on the battery, the fuel gauge went live. At that point in time, I had nothing powered by the ignition switch except the ignition. That meant no tach, either. Fast forward to this past winter (such as they are in the south west), and I had a professional mechanic (who races these 2.0L Mercury 150's) fiddle with the wires in the quadrant in order to get the tach working. Which he did, easily enough. But he said he set up all the gauges to power up through the ignition switch, too. Which I suppose is how it ought to be. Only now, when this happens, the fuel quantity needle drives to zero. So, it still reads right when I turn on the battery master, until I turn on the ignition when it goes to zero.
-Peter
Previously, I had the fuel gauge and sender system wired to the Perko battery master switch. So when I turned on the battery, the fuel gauge went live. At that point in time, I had nothing powered by the ignition switch except the ignition. That meant no tach, either. Fast forward to this past winter (such as they are in the south west), and I had a professional mechanic (who races these 2.0L Mercury 150's) fiddle with the wires in the quadrant in order to get the tach working. Which he did, easily enough. But he said he set up all the gauges to power up through the ignition switch, too. Which I suppose is how it ought to be. Only now, when this happens, the fuel quantity needle drives to zero. So, it still reads right when I turn on the battery master, until I turn on the ignition when it goes to zero.
-Peter