[Powerstroke W/smoke]

So guys i'm replacing the alternator in my boat and the alternator being replaced is a Motorola marine alternator with an external regulator attached to it. I do not wish to run a marine alternator but i'm having issues finding a replacement alternator because there is only one wire running into the external attached voltage regulator and of course the battery wire running to the alternator. Has anyone else had this issue? what do I do?

 

[Mojave85]

Instead of replacing it - why not have the original rebuilt?

 

[Jetaholic]

What you're probably seeing is that your current alternator only has 2 terminals, yet the automotive one has 3. The "3rd terminal" you see on the automotive one is for the idiot light in a car so it won't be used in a boat application. This is also why yours doesn't have that terminal.

On your current alternator (no pun intended), one of those wires comes direct from the battery, the other is switched power from the ignition switch that "excites", or turns on the voltage regulator and turns off the voltage regulator when the key is switched to off.

IMO, get rid of the switched hot wire and run a 1 wire alternator. Simplicity at its finest.

 

[1hotboat]

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X2 IMO that is the way to go get you a one wire alt. I know cheve has a one wire alt. not sure about ford. The cheve would work but the PITA would mounting it.Sure some one on here can hook you up with a set up for ford,you do have a ford?? Good luckdevil

 

[jetboatperformance]

Go with a Marine one wire ($99.00 bucks from us no core ) or... have the Moto' rebuilt (good advice) or call me so I can explain how to wire a "different" one (assuming you go that route) if you run an Auto type you'll have to run a diode in the ignition excite feed or your motor will run even after the key is shut off and for that matter the positive cable pulled etc etc, call my cell if you need to I'll be around tommorow Tom

 

[1hotboat]

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BTW there ia a place off Candelaria and 2nd i think that rebuilds starters and alt. don't know what they charge but maybe worth looking into. PM me if you want to try them and I will get you a PH #devil

 

[Jetaholic]

X2 IMO that is the way to go get you a one wire alt. I know cheve has a one wire alt. not sure about ford. The cheve would work but the PITA would mounting it.Sure some one on here can hook you up with a set up for ford,you do have a ford?? Good luckdevil

On boats, any alternator will work with any engine provided the mounting matches up with the physical size of the alternator and the pulleys line up. They're not engine specific.

 

[1hotboat]

On boats, any alternator will work with any engine provided the mounting matches up with the physical size of the alternator and the pulleys line up. They're not engine specific.

Correct same thing I men to say, mounting is the only thing to deal with. The boat or battery don't care what is charging it. grn

 

[Jetaholic]

Correct same thing I men to say, mounting is the only thing to deal with. The boat or battery don't care what is charging it. grn

Believe it or not, any alternator with an internal voltage regulator can be converted to the 1 wire type. What makes it a 1 wire is the regulator itself. Just change the regulator. They're pretty damn cheap too.

Unfortunately, his probably does not have mounting provisions for an internal regulator. However, he can always buy a used Delco/Remy style alternator with an internal 3 wire regulator and buy a rebuild kit with the self exciting one. Provided the field and stator coils along with the shaft bearings are good they're pretty damn easy to rebuild.

 

[Powerstroke W/smoke]

cool guys thanks for your help, with out it i'd be smacking myself with a wrench haha hammers. I do not wish to have the current one rebuilt because it is older than dirt and I'm sure is obsolete (and only runs on 37 amps lol) The last time we were out at the lake mine took a dump on me. I didn't know that switching from the marine style to the automotive style would be such a hassle lol. but gotta do what ya gotta do.

So, If i choose to go with the one wire alternator, I understand that I connect my battery terminal wire to the alternator, but what do I do with the other single wire that was running to my external voltage regulator which is attached to my old alternator?

 

[Jetaholic]

cool guys thanks for your help, with out it i'd be smacking myself with a wrench haha hammers. I do not wish to have the current one rebuilt because it is older than dirt and I'm sure is obsolete (and only runs on 37 amps lol) The last time we were out at the lake mine took a dump on me. I didn't know that switching from the marine style to the automotive style would be such a hassle lol. but gotta do what ya gotta do.

So, If i choose to go with the one wire alternator, I understand that I connect my battery terminal wire to the alternator, but what do I do with the other single wire that was running to my external voltage regulator which is attached to my old alternator?

Hook it up to a stereo? devil

Seriously, get rid of it. Follow it to where it goes (probably goes to the terminal block on the back of the motor where the ignition connects to) and remove it. That wire on your current alternator tells the voltage regulator to turn on when you turn the ignition on. Not needed with a 1 wire dealio...the voltage regulator self-excites on the 1 wire.

Summit has their house brand 100 amp 1 wire alternators (WAY more than enough) starting at around $80. Not too bad IMO.

Also, if you haven't done so already, if you have a 3:1 crank pulley on the crankshaft (a 3:1 pulley is 3 times the size of the alternator pulley) I HIGHLY recommend replacing it with a smaller one (2:1...2 times bigger than the alt pulley) to slow the alternator down and save the mechanical wear and tear on it. Jet boat engines spin about 1.5 times faster than they do in a car at cruise, and 2-3 times faster around 4000-6000 RPM. You'd be way overspinning the alternator with a stock automotive 3:1 pulley. Slowing it down with a 2:1 pulley will still give you just as much charge voltage and current capabilities as the 3:1...even at idle speed, so why spin it any faster than you need to?

 

[FastRat]

Hey Jet...
could i run the pulleys 1:1 & still maintain a decent amount of charge?...i run a mag & only need to turn the starter ...i also have 2 batteries with an iso switch

FastRat

 

[Jetaholic]

Hey Jet...
could i run the pulleys 1:1 & still maintain a decent amount of charge?...i run a mag & only need to turn the starter ...i also have 2 batteries with an iso switch

FastRat

I've never ran a 1:1 setup before but I've heard of lots who have with great success.

The only place I could even see it being an issue is at an idle. Considering a car that idles around 500 RPM spins the alternator around 1500 RPM (3:1 ratio...3 X 500 = 1500), unless you idle lower than that which I doubt you do, I don't see it being an issue. The advantage you have is the mag...it creates it's own power so that's roughly 5-6 amps (theoretical rough guesstimate based on an MSD 6A that typically draws around 1 amp per 1,000 RPM) less that you're having to pull from the alternator right there. Gauges don't draw shit...even with an electric fuel pump (5-6 amp draw) for the short amount of time that we idle these things I'd say it'd be a non-issue.

If you run a 1 wire alternator, you may have to briefly rev the engine up on start up to get the alternator to "wake up". But as long as you're showing 13.5 - 14.5 volts on the gauge I wouldn't worry about it.