Review on ELING Tachometer Gauge 0 3000RPM Backlight by John Mahfood

Using this tachometer on a Perkins 4.108 sailboat. The 250-amp aftermarket alternator is off most of the time, so the alternator stator pulse will not work with a stock tachometer. My solution was to install a "hall effect" magnetic sensor on the crankshaft pulley. I used the $20 DIGITEN 4 Digital LED Speedometer, RPM + NPN Red Proximity Hall Sensor which also has a 4 digit accurate digital readout. Measured with a manual optical total station, it is very accurate. Luckily this sensor has enough power to run both this (analogue) ELING touch and a digital one from the same sensor. This sensor looks nice and waterproof on the front, but its flaws are on the back. First, all fasteners are plain steel (bolts, bracket, locknuts) so don't mount them near the compass. I used an old plastic speedometer mounting ring which gives the panel a much smoother grip. I coated plain steel bolts and nuts with tef gel to prevent rust. After all the wiring was done, I sprayed the entire back of the tachometer with CRC corrosion inhibitor. I wouldn't trust an electrical connector as it is a water ingress issue. The outer trim ring is non-magnetic stainless steel. The device works great, but let me know - it STEPS in 100RPM increments. This means the dial jumps one tick at a time. No grainy motion, jumps 600, 700, 800 etc no between displays. This is not an obstacle for me, as I have 4-digit displays on the navigation station. Just note that it brews in 100rpm increments, at least when it's set to the 1:1 scale I'm supposed to be using. One more note: The hour meter only counts when the tack counts the revolutions per minute. In other words, don't expect the engine to run and the engine to stay off. I subtracted a star for the magnet steel mounting hardware and 100rpm resolution.