Generator Blues

[hogfighter]

Greetings....

So I have a Northern Lights 6kw generator. When I ask it to draw more than 20 amps at 120vac, it bogs down. I cleaned out the heat exchanger and exhaust elbow, and there was a lot of soot to clean out. However, when I put it all together, it still bogs down above 20 amps. (By bogging down I mean that the generator's rpm drops, resulting in dramatically lower voltage).

It doesn't matter what combination of electronic equipment or bus that I draw the amperage from, and all electronic equipment operates normally off of shore power.

Any suggestions? It runs like a champ below 20 amp draw, no black smoke, etc. I'm thinking governor? Hours are 1,300. Thanks in advance for any advice.

[JustCatamarans]

It could be the govenor not increasing power as the load ramps up.
The NL 6kw is generally a fantastic unit.

Perhaps if you back off one of the speed set screws, and move the lever back and forth to see if it increases the rpms, or is the toggels are sticking?

Kent

[capngeo]

Check the fuel filters, look for an air restriction; intake and exhaust

[DeepFrz]

When was the last time you had the injectors serviced?

[hogfighter]

Thanks CapnGeo, sorry for not mentioning earlier that I changed the fuel and air filters.

The injectors haven't been serviced in a while, DeepFrz. I was thinking it was either the governor or the injectors. I'll try Kent's advice, then if that doesn't help, I'll check the injectors.

[hogfighter]

Today I removed the spring holding the governor arm and reduced the set screw. The arm would only move a tiny fraction of an inch, yet when I did move it counter-clockwise, the rpms did increase slightly. Does anyone with knowledge of this generator know how much the arm is supposed to move? It seems that the engine should be getting much more fuel when loads demand more power, yet it doesn't seem to be doing this.

The folks at my Northern Lights dealer said that they would be happy to pay me a house call for a sizable sum, but were holding the secrets to the governor as if they were with the NSA. Thanks CF compatriots!

[DeepFrz]

Have you seen the new thread on NL generators losing power?
http://www.cruisersforum.com/forums/...tml#post751974

Does it have any relevance?

[hogfighter]

I have, sir....unfortunately, no help. My genny and engine both run off of my racor, and it has no air in it, engine runs like a top.

[HopCar]

Just for fun, check the screen in the fuel pick up tube. It really does sound like a fuel restriction. I removed the screens from my pick up tubes. I want the dirt to go through to the filter where it is easy to get rid of.

[hogfighter]

Originally Posted by HopCar

Just for fun, check the screen in the fuel pick up tube. It really does sound like a fuel restriction. I removed the screens from my pick up tubes. I want the dirt to go through to the filter where it is easy to get rid of.

Hmm...you may be on to something. I'll check it asap. Thanks.

[hogfighter]

Resurrecting an old thread, as someone else has let me know they are experiencing the same symptoms that mine had. My result was that the injector pump had a faulty, but not totally blocked, line to the third cylinder. As a result, the cylinder was not firing correctly, which in turn blocked up the exhaust elbow with soot, which in turn backed up sea water into the valve spring area, which in turn corroded the valve springs necessitating a valve job. This domino effect happened shockingly fast.

SO.....after cleaning out the exhaust elbow, getting the valves replaced, and getting the injection pump rebuilt, she now runs like a top. Bottom line, the maximum load that the generator could bear was about half of its rated power since one of the three cylinders was not firing correctly. I hope this helps anyone else who may be experiencing the same symptoms.

[bstreep]

Thanks, it's always great to get the ultimate solution to a problem. Folks often forget to do that.

[Dreaming Yachtsman]

Hogfighter (Kevin) revived this old dormant thread at my request because my NL 6KW (Model M673L) generator started having almost the exact same problem two days ago: black smoke and severe loss of power. I checked easy stuff first: cooling water strainer was clean; raw water pump impeller was intact and rotated when the engine turned over (have had recurring problems with the nut holding the drive gear on the pump shaft coming loose). Ran engine, same problem.

Changed fuel filter. Ran engine and sprayed fuel all over because of paint on the bleed screw washer. Cleaned off paint, no more fuel leak but the engine still had no power and put out loads of black smoke. (This engine is equiped with a GenSep™ downstream of the muffler to separate cooling water from gaseous exhaust after it has been cooled. Water discharges below the water line, gas above. This device was sold to me so that I wouldn't bother neighbors in anchorages with exhaust water splashing when running the engine.)

Consulted by phone with my brother who is an excellent John Deere repair technician and knows diesel engines inside and out. He suggested an air restriction but we ruled that out as I had recently replaced the filter element and there is nothing between it and the intake manifold. We essentially ruled out injector problems because the engine started easily and did not miss or run roughly. He did say that to isolate a malfunctioning cylinder, measure exhaust manifold temperatures - the malfunctioning cylinder will run colder than the rest.

Based on OP's original post and because black smoke came out both the gas exhaust and the water discharge, I suspected the exhaust mixing elbow. Sure enough, when I finally got it off, it was almost completely clogged. I scraped out as much carbon as I could with a screwdriver, soaked the elbow in 50% vinegar-water solution, rinsed it and let it dry.

Reassembled the engine and it ran under full load like a champ.
Lesson learned here: Run the engine heavily loaded more often to keep the carbon from building up.

(I must be really dense because that's the same lesson I learned the hard way with my main propulsion engines: Exhaust Mixing Elbow Inspections)

[hogfighter]

I'm glad that it was a relatively easy fix, and not expensive! Mine was clogged as well, but had too few hours on it to be as clogged as it was. It might be a good idea to take off the valve cover and check the valves, just to make sure they are nice and clean. Mine were corroded from sea water intrusion. Best of luck - K