Re: has anybody?
Hey Shipwreck,
From what I understand, an automotive Tach won't give you an optimum reading in any marine application. Is this an inboard or an outboard application?
For inboard there are some who say that it can be done but the truth is that the materials used in the manufacture are generally not marine grade and the units are not water sealed. Even if it works at first, eventually it will misread and slowly deteriorate and you will have to replace it. Nothing worse than trying to read a gauge with condensation on the glass INSIDE the gauge.
For Outboard use the answer is absolutely NO....on certain two-stroke applications where points and an ignition coil are NOT used any hope of connecting the gauge would be useless.
Every other tachometers for two-stroke application must be calibrated at the factory specifically for that purpose.
As far as the wiring, that is simple...Most tachs have two to four wires. (for a two wire tach) one wire connects to a rectifier that outputs and reads the electrical current being output from the alternator/generator and interprets that voltage to indicate revolutions of the motor (That is why it must be calibrated at the factory for accurate read. (If you have a four wire) the other two generally are just for a light source within the gauge and one side goes to positive side of the battery and the other to ground for the bulb.
This is a general explanation but I hope it helps...
