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Old 03-08-2020, 14:04   #1
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Trouble with my Northern Lights 8kw

Hello all.
Salt water coming through the exhaust manifold/expansion tank and then through the coolant recovery tank with pressure to the floor.
Model #: M673L3.3. 8KW.
I have a problem and how can I fix it?
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Old 03-08-2020, 18:18   #2
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Re: Trouble with my Northern Lights 8kw

Quote:
Originally Posted by Laksmi View Post
Hello all.

Salt water coming through the exhaust manifold/expansion tank and then through the coolant recovery tank with pressure to the floor.

Model #: M673L3.3. 8KW.

I have a problem and how can I fix it?


I donít quite understand what you mean by expansion tank. But you do have a heat exchanger in there with multiple rubber couplings on it. If you have seawater in your coolant, then the problem is with your heat exchanger. It will need to be disassembled, cleaned and or replaced as necessary. If itís old, replace all the rubber parts too.
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Old 03-08-2020, 19:10   #3
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Re: Trouble with my Northern Lights 8kw

Thank you Captain Bligh. Yes, exactly the way you described. I will dissemble the heat exchanger and go from there.
I do appreciate your help.
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Old 03-08-2020, 20:06   #4
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Re: Trouble with my Northern Lights 8kw

Do not reuse any O-rings In the heat ex, use new ones.
You May consider pressure testing the fresh water coolant system after reassembly, if so be careful to not put to much pressure on it.
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Old 03-08-2020, 20:15   #5
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Re: Trouble with my Northern Lights 8kw

Thank you a64pilot, I will keep it in my mind and for sure will change all rubber materials
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Old 03-08-2020, 22:14   #6
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Re: Trouble with my Northern Lights 8kw

I had this with my Kohler 6.5EFOZ. Years ago.


The cause was a perforated heat exchanger due to my ignorant unawareness that there is a thin pencil anode in there which must be replaced often.



Cure was a new heat exchanger.


Be sure to flush the hell out of the fresh water circuit to get all the salt out. Then replace the coolant often afterwards.
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Old 04-08-2020, 05:18   #7
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Re: Trouble with my Northern Lights 8kw

Believe that generator uses the same engine and heat exchanger system as the Perkins Perama M and Volvo MD20XX engines, based on the ISM 100 series engines. The salt water and fresh water is segregated by the sealing of the rubber boots on each end of the heat exchanger. Careful cleaning, inspection and reassembly of the various parts may solve your problem; pay close attention to the rubber boots, they should be flexible with no attached internal scale. The heat exchanger bundle should be centered in the heat exhanger housing to allow maximum contact of the sealing areas of the boots on both the bundle and the housing. The hose clamps should be in good condition and well tightened. If there is corrosion in the water inlet at the exhaust mixing elbow, any restriction can cause excess pressure in the raw water side, which can force sea water into the freshwater side.

New boots are available from a variety of sources, Northern Lights, Perkins, Volvo and aftermarket suppliers all have them
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Old 04-08-2020, 08:44   #8
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Re: Trouble with my Northern Lights 8kw

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Originally Posted by Dockhead View Post
I had this with my Kohler 6.5EFOZ. Years ago.


The cause was a perforated heat exchanger due to my ignorant unawareness that there is a thin pencil anode in there which must be replaced often.



Cure was a new heat exchanger.


Be sure to flush the hell out of the fresh water circuit to get all the salt out. Then replace the coolant often afterwards.
Thank you Dockhead.
I will check those as well for sure. I feel more confident with all those input.
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Old 04-08-2020, 08:52   #9
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Re: Trouble with my Northern Lights 8kw

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Originally Posted by jimbunyard View Post
Believe that generator uses the same engine and heat exchanger system as the Perkins Perama M and Volvo MD20XX engines, based on the ISM 100 series engines. The salt water and fresh water is segregated by the sealing of the rubber boots on each end of the heat exchanger. Careful cleaning, inspection and reassembly of the various parts may solve your problem; pay close attention to the rubber boots, they should be flexible with no attached internal scale. The heat exchanger bundle should be centered in the heat exhanger housing to allow maximum contact of the sealing areas of the boots on both the bundle and the housing. The hose clamps should be in good condition and well tightened. If there is corrosion in the water inlet at the exhaust mixing elbow, any restriction can cause excess pressure in the raw water side, which can force sea water into the freshwater side.

New boots are available from a variety of sources, Northern Lights, Perkins, Volvo and aftermarket suppliers all have them
Thank you jimbunyard.
More info is greatly appreciated, I will proceed carefully with a lot of awareness
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Old 04-08-2020, 13:06   #10
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Re: Trouble with my Northern Lights 8kw

There is not (no, none) pencil anode in our 8 kw Northern Lights generator. Be sure to track your model carefully by calling Northern Lights. Some have anodes, some do not.



We did have a similar issue, but no drop in pressure, just the thorough mixing found on the annual change of impeller. Who knows if it was fortuitous find.



(1) Change impeller annually regardless of hours or based on hours --- whichever is shorter time.



(2) If any of the impeller is "missing" any piece, no matter how small --- gotta find the piece.



(3) Ream the heat exchanger until it's clear. Run some Barnacle Buster through the raw water intake system.



This worked for us. No problems since.



Looking for some errant piece of the impeller is a job. We were not late nor did we ever forget to change the impeller. We went to replace the impeller on an annual check. Butta-bing, butta-bang. Impeller had a small tear, two small missing pieces. Coolant had raw (salt) water in it.



A fiddley job for sure. We run this generator daily for 1 to 8 hours at least 6 months of the year, and never go a week without running the generator.



Generators that are unused develop these "kinds of problems" per Northern Lights. This was 3 years ago and things seem to be going well.



Good luck.
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Old 04-08-2020, 15:19   #11
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Re: Trouble with my Northern Lights 8kw

Your heat exchanger sounds as though it is leaking internally--and to you need to shut everything off and remove it and have it replaced or repaired if the fault is not too serious..
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Old 04-08-2020, 16:13   #12
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Re: Trouble with my Northern Lights 8kw

Thank you Mike. It is internally for sure.
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Old 04-08-2020, 16:20   #13
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Re: Trouble with my Northern Lights 8kw

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Originally Posted by Laksmi View Post
Thank you jimbunyard.
More info is greatly appreciated, I will proceed carefully with a lot of awareness
The only further information I could give would be an illustration, so see below.

If this is what your cooling system looks like (there was a keel and radiator cooled version in the parts manual as well), the common problem areas are as follow.

A are the points to pay attention to to avoid sea water mixing with the freshwater. The bundle 11 should be positioned longitudinally so that equal amounts stick our on both ends of the tank/manifold so that the center section of the boots 12 seals against the maximum amount of area. Make sure that the inside of the boots are clean and that the mating area on the bundle 11 is bright metal.

B are the points that seal the fresh water into the heatexchanger/manifold. The same conditions as for A above should be followed to prevent external leaks of engine coolant.

C is the point to check for restriction in the water outlet. If the elbow has restricted water passages, the unrelieved pressure from the raw water pump can push sea water into the fresh water side. Usually this is accompanied by swelling of the boots 12 as engine speed increases (though with a generator the speed should be constant).
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Old 04-08-2020, 16:22   #14
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Re: Trouble with my Northern Lights 8kw

Thank you all, I really appreciate all of you who have made an effort to help me.
I have dissembled the exhaust manifold heat exchanger. And have found the riser block with black stuff. The riser is made of steel and might be compromised. Itís now in the shop and will be cleaned or change to Stainless steel. Will let you all know soon.
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Old 04-08-2020, 16:28   #15
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Re: Trouble with my Northern Lights 8kw

Hi Jim
Number C is the culprit. I’m learning everyday and happy about it.
Thank you
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