Alt on my 1997 Mariah 180 se Shabah charging at 15 volts


Jul 22, 2011
I have a 1997 Mariah Shabah 180se. 4.3GLPLKD, I just bought the boat and I notice it was charging 15 volts anytime it is off idle and 14.5 at idle. I replaced the alternator and that did not help new alt does same thing. It is a mando type alternator. I put all the wires back on like they came off but does anyone have the schematic or image that shows the correct location of the wires. If I did hook it up correctly what can I check. I checked for voltage at Alt positive cable and positive cable at battery and voltages were the same. I have battery voltage at purple wire at exc terminal with key on and none when key off. I have small jumper wire that goes from exc terminal to S terminal that is red/white and is made onto purple wire at exc terminal. What are the chances of having 2 alternators having the exact same problem? I have read it should not charge over
14.2v and have verified the readings I have with a volt meter.
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Rear Admiral
Mar 26, 2005
Re: Alt on my 1997 Mariah 180 se Shabah charging at 15 volts

First welcome to iboats

Getting a high output voltage on brand new alt- verify your ground connection

You will also get better results posting in the I/O forum instead of being burried way down here in the manufacturer forums...