Home › Forum › Ask A Member › Boat Tach on car › Re: Boat Tach on car
That’s not a bad idea, I might try that if it’s not compatible.
I’m definitely going to try it out first just to see if it’s anywhere close to working, but where should I hook it up to on the alternator? It’s got 4 posts coming out of it, one being ground. I’d post a picture, but it’s pushed in the garage now and I can’t get around it to open the hood…
Not being familiar with your specific alternator, it’s a pretty darn safe bet that you would have to take it apart to access the AC voltages (ahead of the diodes). I’m guessing there are six diodes in there, 3 negative and 3 positive. After the diodes would be the DC output at one of those posts. Another post probably is voltage regulator input and the third maybe is reference voltage to the regulator. Most of this is just uninformed guessing though. Except for the diodes’ location. You can almost take it to the bank that they are internal. That tach is designed for OMC outboards that have an external bridge rectifier (4 diodes), and access to the AC side is easy. BTW, the tach on my own boat looks exactly like yours but it has a pulse selector switch on the back. My motor is 5 pulses per rev.