Alternator wiring correct?

[Richard R]

S/U: 87 GM 4.3 / OMC, 17' Seaswirl<br />Old alternator case broke and I just replaced my alternator and have two questions regarding charging and wiring.<br />The new alternator is a 68 amp 3 wire, the old one was 51 amp 3 wire.<br />Concerned that I don't burn up my battery.<br /><br />The battery was charged and in good condition, we were out for a couple of hours, running off and on and the volt meter is staying at around 14.0 volts. Shouldn't it fluctuate, drop some after being ran for a couple of hours?<br /><br />One reason for my question is as mentioned above the alternator is a 3 wire, one wire (about 12 gauge) is obvious as to where it goes, however the new alternator does not have the other two wires (about 16 ga) "marked" lugs for the sensor / exciter like my old one did. I am 99% sure I got the two wires correct but I thought I would ask the pro's!! <br /><br />What would happen if they were switched, any of you brave hearts tried that yet, any smoke? <br />Is there a way to verify the connections are correct?

 

[Boatist]

Re: Alternator wiring correct?

Doc Water<br />I can not help you with wiring and am a little confused. You say both are three wire systems but then only talk about two wires??<br />Anyway 14.0 volts is fine. If it ever goes below 14 volts while running it is time to worry. Remember this is not a amp meter but a voltage meter, and when working correctly should stay at the same voltage. If battery is really run down can take a while to charge up to 14.0 but with a 68 amp alternator should get there quick. If it should charge up 16 volts angine time to worry.

 

[Richard R]

Re: Alternator wiring correct?

hummmm... sorry.. it's like trying to write documentation for a program, never seem to be able to get it clear for everyone.<br /><br />For anyone who might have information maybe this will help clear up the three wires.<br /><br />I eliminated the first wire in the third paragraph, first line of my original post. <br />On the motor side the one red 12 gauge wire, is obviously the main battery wire, red, booted the whole enchilada, no questions about it. It goes to the only lug on the new alternator.<br /><br />On the motor side, the two 16 gauge wires, one is purple and one is red with a purple stripe are the ones that I have questions about.<br />The alternator has one black wire and one red wire coming out of a black plastic "box".<br /><br />One other note, may be related. We were out yesterday and I noticed that at WOT the motor sounded like it was "taching out" around 4300 but the tach only read 3200. But at an idle it read fine, then later on in the day WOT was back to 4300.<br /><br />Any thoughts?