Just wondering if anyone has any ideas. I just bought a 77 spectra 18. The voltmeter on the dash stays right at 12 volts when the boat is running. I checked it with my voltmeter at the batteries and 12 volts also. I also checked it at the alternator and it shows nothing. The wire that is conected to the alternator (bat) should show 12 volts, right. It shows nothing. That wire runs to a breaker switch and then to the wire block that says ALT. Is there anywhere I can look at a wiring diagram for this boat? I think the problem is with the wiring because the wire running to the alternator should be hot (12 volts) and it is not. Any ideas?
Thanks,
Keith

I think most systems run more like 14 volts don't they? Most alternators you can tell if they're charging, the back side in the center will be magnatized(sp?), or just run it to checker and have it tested. Just read your post again, and it reads zero???

my experiences, the battery should be right around 12 volts when the engine is off. when the engines running you should seeing between 12 and 14.5ish, depending on RPM's and load. if u are not getting above 12 with the engine are chances are your alternator is toast. if your below 12 with the engine off with a battery that is charged then your battery is toast(or u have lost 1 or more cells).

hope that helps

So are you gonna tell us what the problem was or not

Not on purpose

Sure.. The ALT was hooked up wrong. The charge wire hooked through the breaker switch and then to a wire that was labeled ALT. That wire ran to the underside of the dash board and was not conected to anything.  It looked like the wiring was not completeed after the ALT and gauges were switched. I ended up just running the charge wire to the battery side of the starter selinoid.   

Sounds to me the boat used to have an ammeter... Good find bro 

GT