Northern Lights Generator Problem

My generator starts easily and seems to run normally, but I am concerned about the exhaust system.* During the first 30 seconds of operation, the wet exhaust "spurts" the water out with good force.* However, after a short time it goes to a really small "trickle", and actually appears that it is trying to exhaust in reverse.* I can see below the water line and it appears like the "outflow" wants to use the intake thru hull.
I have changed the impeller with no success.* I'm afraid to run the generator for any extended length of time.
It also seems that there is a small leak around the impeller area.* A new gasket and "O" ring was installed during the impeller change, so that shouldn't be a problem.
Any suggestions, other than a prescription for Flowmax, would be appreciated.
Thanks.

Sounds like to me that pieces of the old impeller are moving around down stream of the pump. My 12.5 NL has a hose just in front of the heat exchanger that is easy to remove. I use a pair of quilting tweezers to fish the pieces out. If they are moving they will intermittently partially block the heat exchanger and they will fall back down the hose and ruin the impeller that you just installed. I would say the first step would be to remove the pieces that may have been in there from several prior impellers and then pull the new impeller. NL's are bad about this problem.

Also while you have the impeller out it would make sense to install and new cam and wear plate. I don't know what size your NL is but mine uses only an O ring. The kits come with both. Did you install both?

If Doc's suggestions don't resolve the problem I would suggest calling Northern Lights in Seattle and describing the situation.

Wow Marin, Call the manufacturer? What a concept

Radical idea, I realize. It always surprises me on forums like T&T when people post something about a problem with an FL120, for example. They get a dozen or so speculative answers, many of which cite experiences with other types of engines as the reason for their suggested solution, when all it takes is a single phone call to American Diesel. Or second best, a call to a professional diesel shop with experience with these engines.

Or questions like "My Force 10 oven burner won't stay lit. Any ideas?" You'll get a ton of them on a forum but make a single phone call to Force 10's outstanding customer service department (as we did when we had this problem) and you get an immediate explanation, the remedy, and in our case, the improved gas valve component was FedExed to us for free and when we got it the service guy at the factory talked me through the installation on the phone.

Hello All

The following is something that occurred with our Northern Lights gen-set. and I thought this might be of help should the same thing happen to someone else. Especially on a trip!!!!

The raw water pump was leaking, and it was discovered there was a chunk of blade missing on the raw water impeller. While the boat was laid up at Seaview West at Shilshole Seattle, I had the pump seals and impeller replaced by Paul at Northern Lights, just down the street from Shilshole. After the pump was re- installed and boat back in the water, I ran gen-set to test for any leaks after replacement of water pump seal and new impeller. Everything seemed fine for around ¾ of an hour, until ready to shut the unit down when I noticed steam coming from the gen-set. After shutting the unit down, I found raw seawater accumulating in and around the base of the unit and in the bilge. Further examination revealed that the cooling system recovery bottle was full of seawater and was overflowing out into the gen-set box

See Northern Lights Parts Catalog M673LD2 page 3-0 for descriptions

After talking to Paul at Northern Lights the cause is most likely either some type of obstruction restricting seawater flow through the heat exchanger, causing a back pressure in the heat exchanger and compromising the seal at clamps (14) on the rubber boot, thus allowing an intermixing of seawater and coolant, or one or both clamps (14) are simply loose.

The fix was as follows:
1. Drain remaining water in block through the valve near oil dip stick.
2. Remove forward rubber boot joint (12) from exhaust manifold expansion tank (1).
3. Pull out heat exchanger (11) from exhaust manifold expansion tank (1).
4. Inspect and clean tubes in heat exchanger (11)
5. Remove rubber boot joint (12) from the other end of exhaust manifold expansion tank (1).
6. Inspect exhaust elbow (6). Note: On the top of the elbow where the rubber boot joint attaches, inside the hole there could be blockage here or inside the elbow.
7. Clean and dry back rubber boot joint (12) and replaced onto exhaust manifold expansion tank and exhaust elbow fittings.
8. Replace the heat exchanger (11) into forward end of exhaust manifold expansion tank (1) with the holes in the heat exchanger cylinder pointing down and allowing about 2MM of the heat exchanger cylinder to protrude from expansion tank. This allows for the other end of the heat exchanger cylinder to slide into place inside the back rubber boot joint that is already in place on the expansion tank.
9. Clean and dry the forward rubber boot joint (12) and placed on the forward side of the expansion tank (1).
10. Tighten forward and back rubber boot joint clamps (14) that create the seal on the heat exchanger cylinder. These are the clamps closest to the elbows of the rubber boots (these must be tight to create the seal preventing seawater and coolant intermixing), not the clamps that hold the boots to the expansion tank. Then tighten the clamp holding the back rubber boot to the exhaust elbow (6).
11. Tighten both rubber boot joint clamps at the expansion tank (13).
12. Fill through the exhaust manifold expansion tank (1) filler cap fresh water until tank and block full. Then drain out all water, repeated 3 times.
13.Fill block and expansion tank with fresh water and with filler cap off, run engine with fresh water in expansion tank and block until water is hot and check for leaks, make sure water level at filler is not rising. Stop engine, drain, repeated 3 times. Check for leaks.
14. Drain all water from expansion tank and block. Replaced with just under ½ gallon 50/50 mix of Havoline Extended Life Anti-Freeze / Coolant, replace filler cap.
15. Run gen-set for 1 hour with at least 3500 W load, check for leaks and any sign of seawater back filling into cooling system recovery bottle. Watch for water temperature to remain at or under 180 F for entire run.
16. Spray all surfaces that were exposed to salt water with Salt Away and wipe clean. Electrical connections spray with WD-40. Engine mounts spray with WD-40. Bilge areas pump dry and wiped clean.
17. After gen-set run and after cool down, check fluid level and add 50/50 mixture to recovery bottle.

Lessons I learned because of this: Anytime there is a chunk of impeller missing, find where it went. Clean the heat exchanger and exhaust elbow. As per owners manual instructions, remove and clean heat exchanger once a year but In addition to this, inspect exhaust elbow for obstructions and Inspect raw water impeller. Although my problem was caused by pieces of impeller clogging the exhaust elbow, it is a very good idea to regularly check rubber boot joint clamps (14) are tight. Should one or both of these become loose, the raw water and engine coolant will intermingle causing the engine to flood with seawater.

SteveH

Great info- welcome aboard Steve. What sort of ship do you have?

Thanks, our boat is a North Pacific CHB 36 Europa style. - SteveH

Cast Bronze In-Line Strainers
Seacock up to 1" ............................................................................... 0029S
Seacock up to 1-1/4"............................................................................0029


From the Sendure catalog, the cure we have been using for almost 4 decades.

Install one of the Y strainers after every small engine( they are only 1 1/4 pipe thread) rubber impeller pump.

When , not if the impeller takes a crap , the parts will be a few seconds to remove from the strainer basket.

In sailing aux with sea water cooling we install 2 , one for sea water pump, second for circ water pump.

Steve,
I have talked to Trevor a few times on the phone and he seems like a great guy. I am very impressed with their product. I have an '83 CHB and it seems that NP has continued the tradition.

And last but not least, change those impellers annually (anally as some say) and you'll largely negate the* chase of*missing pieces. It is amazing how many wait until overheating occurs to change impellers - all to save a few bucks or just unaware

-- Edited by sunchaser on Friday 16th of April 2010 11:54:38 AM

Hi Forklift

Yes, Trevor is very personable, easy to work with and stands behind his boats. He has a very nice line of boats to include the NPY 38, which is the replacement to my boat. Really the same boat but with a little more elbow room. - SteveH

I went to the boat this weekend and disassembled the hoses and exhaust elbow to the heat exchanger. Indeed, I did find six or seven "fins" from previous impellers.
However, when I put everything back together, it still did not push water through the exhaust thru hull.
I did notice that when I closed the seacock to the lift "muffler", the exhaust pushed water through the above- the-waterline thru hull with tremendous velocity. As soon as the "muffler" seacock was closed, the water ceased to pass through exhaust thru hull.
It seems that the seacock should be left open for normal use, but perhaps I am wrong and it should remain closed.
Am I missing something here?

-- Edited by ChuckB on Sunday 25th of April 2010 05:25:55 PM

What kind of installation is this? I have an underwater exhaust on my generator and it only spits a tiny amount of water out of the above the waterline bypass. Everything else is going out underwater.

The exhaust exits the generator and goes to a black box mounted on the aft engineroom bulkhead.* A hose, with the seacock, comes in to the black box from below the waterline.* Another hose goes from the black box to the above-the-waterline thru hull.*
Yes, it does look like the exhaust is being emitted below the waterline because I see some bubbles and water flow underwater.*
However, it seems to me that the lower hose should somehow be bringing seawater into the muffler and the top hose should be exhausting the combination of water and gases.
It just seems that the above-the-waterline thru hull should be discharging more than a dribble.
Doc, this is a Nordic Tug 32 with the Northern Lights, Lugger, generator.


-- Edited by ChuckB on Sunday 25th of April 2010 05:56:25 PM

Sounds like a standard water-separator exhaust to me.

Stops the annoying spitting sounds that normally go with genset exhausts. The below-the-waterline thru hull is the cooling water exit and the above-the-water line, the exhaust gas exit.

If you close the seacock on the below-the-waterline thru hull, all the water will be forced out above the waterline. This the way to check that there is adequate water flow and the pump/impeller is OK.

-- Edited by Bendit on Sunday 25th of April 2010 07:28:20 PM

-- Edited by Bendit on Sunday 25th of April 2010 07:28:53 PM

Chuck,

You found more pieces of the impeller. Good. You have a Nordic Tug which has the same exhaust plumbing as my 42 NT. Sounds to me that if your generator temp is OK that nothing is wrong.

Mine barely spits above the water line. If the spit stops and the temp guage is up a little I know that it has eaten its impeller. If it gets hot it will shut down.

I have never closed the sea cock as Bendit suggests, but what he says makes sense to me.

Chuck
I would agree with Dock, things sound normal. From what you have explained, you have a lift muffler attached to a water / exhaust separator. The raw water exits below the water line and the exhaust gas exits above the water line. Keep the seacock open when running the gen-set. - SteveH

-- Edited by SteveH on Monday 26th of April 2010 09:43:15 AM