I have a 1989 34' Black Watch with twin 454 Crusaders. I broke off the stud for the "EXC" wire while changing the belt. The motor still cranks but have not taken her out for a spin. What does that wire go to? Is it needed? Also it is made by prestolite, who is no longer in buisness, what is an acceptable aftermarket replacment?

do you mean the exciter wire on the back of the ALt ??????

do you mean the exciter wire on the back of the ALt ??????

damn did it twice

Yup.  Does it run to the coil?  I

It literally excites your alternator by giving it a little boost of electricity, it helps the alternator to start producing its full charging capability.

Edited

do you mean the exciter wire on the babk of the ALt ???

Take it off and bring to a rebuilder, they can fix it for about $35-50 including putting in new brushes and testing output. Or buy a new single wire (just need to hook up the large red or orange wire to the output stud. Any GM alternator will work, just make sure it is a proper marine config with the flame arrestor screens in it.

ETA check to see if the pulley diameter is the same with a replacement, you can swap over most but some have different shaft diameters/flats on them. The swing bolt boss and tensioner flange are all the same with the Delco/prestolite GM alternators used on GM based marine engines. For the most part)

Here is on on Amazon, a 110amp new for $65. It's a single wire. You may have to connect a keyed hot  (purple color) wire to the choke coil to use this type. Link

do you mean the exciter wire on the babk of the ALt ???

Awesome guys, thanks for the replies!  It hadn't even crossed my mind to have it rebuilt...

Hey guys thanks for the advice.  Going with a rebuild, it was much cheaper and the stud will be replaced with a new voltage regulator.  thanks for help will update when complete.