Northern Lights 20kw (original 1981?) - Crapped out ...

[Buccaneer]

I'm told that the "back end" of the existing "front" NL 20kW genny (186 hrs!) on a 1981 61 MY I'm looking at has crapped out and needs to be rebuilt.
The other "back" NL 20kW genny (w 900+ hrs) is running just fine. (I'm told.)

So, what's it likely to cost me to have it rebuilt (the back end...? whatever the hell that means) or to replace?
I've read on this forum that the NL is "bullet proof" - if maintained. So ...

What say y'all?

 

[SKYCHENEY]

Back end is the generator part, not the engine

 

[Pascal]

Yes the back end is basically the alternator and the associated wiring incl regulator.

Yes NL are as good as it gets but if they are original they are over 40 years old. How many hours does it have total? Can’t be 186…. 10k+ hours is common for these.

Getting parts may be tricky although NL is pretty good for that. Did they even make their own alternator or did they use off the shelf alternators like Marathon?

 

[Avenger]

I'd say get a second opinion from someone who will diagnose it and actually tell you what's wrong with it, other than "it's shot."

Unfortunately, there's a few marine mechanics that aren't really interested in repairing generators, or the clientele isn't willing to pay for diagnostic time. A lot of generators get replaced based on math that ends with "for a few dollars more you can get a new unit."

Unless it was grossly overloaded, or drowned I find it hard to believe a 186 hr generator needs a rebuild. However, if it does look up Broward Armature in FL.

 

[Captain Ralph]

Electrical ends can stop making power for many reasons, including 43 year old windings failing.
AVR failing.
Exciter diode failing.
Bad wire crimp.

Broward Armature in FL just repaired and rewound the later 20KW in for a friend.
$4600 was the estimate. Then the armature was found not re-usable. A good core was found and rewound. Not sure what extra charge there was there.

I have found 15 cent crimps come apart from an AVR wire.

So there ya go, it may cost 15 cents to near $5k to fix.

May I suggest finding a real tech to tell you what is wrong with the generator end?
Maybe he has checked it all out and his communications skills just suck. A second attempt of explaining what part of the back end is dead may need re-visiting.

 

[jim rosenthal]

I think Northern Lights used bought-in generator ends like Marathon or Newage. Assuming the engine section of the generator is good, it might be better to just replace the generator end and the control boards.

NL are very good gensets. Most yacht sets don't get enough usage- I know mine doesn't. I think they do better when they are regularly used under load.

 

[Buccaneer]

Yes NL are as good as it gets but if they are original they are over 40 years old. How many hours does it have total? Can’t be 186…. 10k+ hours is common for these.

Getting parts may be tricky although NL is pretty good for that. Did they even make their own alternator or did they use off the shelf alternators like Marathon?

No kidding ... that's what I thought, 10,196 not 196. But the seller (and her broker) are stating otherwise. I'd bet that the seller ran the 2d genny (but even then - only 900 hrs on the second one??? ) and never bothered with the first one.
I mean, did anyone even think to use inverters and install a much larger battery bank on the 61s back in the 1980s or 1990s? Everyone ran the genny...

I expect I'll be looking VERY closely at both these generators.

 

[Pascal]

Are they really original to the boat? I thought hatteras mostly used Onans

 

[Captain Ralph]

One other thought.
Ultra low hours on a 23 year old gen set.
So, it has just been sitting in an engine room, collecting dust, collecting rust, collecting moisture??

Cruel and unusual abuse.

 

[JD5652]

If you decide to replace it, it's about $25K just for the genny, then installation costs. Just replaced one myself about 1.5 years ago. Had 8900 hours on it. My other NL 20kW has about 8300 hours and the back end has been replaced before my ownership.