Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-08-2017, 10:34 AM   #1
Senior Member
 
Islanddreamer's Avatar
 
City: Kingsville, MD
Country: USA
Vessel Name: Harmony
Vessel Model: Pacemaker 1990 37' Convertible
Join Date: Mar 2016
Posts: 285
Generator heat exchange failure?

Northern Lights M673M 5.5kW older generator but with <300 hours. As a routine maintenance last year had the HX removed, cleaned out, and put back in place. Winterized prior to HX cleaning. Not sure if it is original - have had the boat for a little more than a year. The way the gen was installed, I needed to have someone shorter, thinner, and more flexible than me get to the non-routine service side of the gen - hence having it done versus doing it myself. I can get easily to the other side of the engine.

Fired generator up and drip pan had diluted antifreeze in it. Vacuumed up the mess. Cleaned pan. All connections are tight and not leaking - no leaking hoses. Did the same routine, but this time the Admiral fired the gen up while I was in the bilge with the sound shield off. After about 3-5 seconds of running, a mix of water and antifreeze was coming out of the overflow tube - which I caught in an empty water bottle this time to avoid the cleanup. Thought it was odd that I didn't need to add a lot of antifreeze after HX was repaired.

Here is the question - if a tube in the HX fractures, the overboard water will enter the block and the only way out is the overflow tube - correct? Again - everything is tight except that when the gen runs, coolant / water streams from the overflow tube.

Advice?

mike
__________________
Advertisement

__________________
Any day aboard is a good day.
Islanddreamer is offline   Reply With Quote
Old 05-08-2017, 11:07 AM   #2
Guru
 
twistedtree's Avatar
 
City: Gloucester, MA
Country: USA
Join Date: Jan 2013
Posts: 4,949
Do I understand that you just serviced the heat exchanger? I'm not sure about the 5kw, but the larger NL gens have a special boot that forms the seal/barrier between the sea water and coolant sides of the heat exchanger. There boot needs to be positioned correctly, and the two clamps need to be in the correct location, and tightened in the correct order to get a good seal.

That may be the only issue. But if it is, you will need to go a thorough coolant system flush and add all new coolant.
__________________

__________________
www.MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 05-08-2017, 11:20 AM   #3
Senior Member
 
Islanddreamer's Avatar
 
City: Kingsville, MD
Country: USA
Vessel Name: Harmony
Vessel Model: Pacemaker 1990 37' Convertible
Join Date: Mar 2016
Posts: 285
I replaced the boots as well because they had buildup, and they were reinstalled. As to correctly - I cannot say because it wasn't me - but someone I trust. When I'm done, I'll need to get Middle River out of the block!
__________________
Any day aboard is a good day.
Islanddreamer is offline   Reply With Quote
Old 05-08-2017, 12:13 PM   #4
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 5,359
Some coolant will get expelled due to thermal expansion. Maybe a couple ounces from cold to warmed up. If boot leaks, sea water will mix with coolant and if you run it with cap off, the mix will come out continuously.
Ski in NC is offline   Reply With Quote
Old 05-09-2017, 06:01 PM   #5
Senior Member
 
Islanddreamer's Avatar
 
City: Kingsville, MD
Country: USA
Vessel Name: Harmony
Vessel Model: Pacemaker 1990 37' Convertible
Join Date: Mar 2016
Posts: 285
Quote:
Originally Posted by twistedtree View Post
Do I understand that you just serviced the heat exchanger? I'm not sure about the 5kw, but the larger NL gens have a special boot that forms the seal/barrier between the sea water and coolant sides of the heat exchanger. There boot needs to be positioned correctly, and the two clamps need to be in the correct location, and tightened in the correct order to get a good seal.

That may be the only issue. But if it is, you will need to go a thorough coolant system flush and add all new coolant.


twisted tree- the boot was the problem. There is such a small margin for error it is amazing. You can't count on the old marks where the old one came off either. Thank you- you saved me considerable stress.

mike
__________________
Any day aboard is a good day.
Islanddreamer is offline   Reply With Quote
Old 05-09-2017, 06:57 PM   #6
Guru
 
twistedtree's Avatar
 
City: Gloucester, MA
Country: USA
Join Date: Jan 2013
Posts: 4,949
Cool. Glad you got it fixed. I had to remove one of my boots to fish out some impeller blades, and had to fortune of NL's training guy coaching me. I likely would have screwed it up otherwise.
__________________
www.MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 05-09-2017, 07:08 PM   #7
Guru
 
Rebel112r's Avatar
 
City: Birch bay wa
Country: USA
Vessel Name: Rogue
Vessel Model: North Pacific 42
Join Date: Feb 2013
Posts: 561
I would bet, the exhaust elbow is plugged up and salt water pump is forcing sea water by the o rings in exchanger. I have the same gen, and had the same troubles when I bought the boat. Easy fix, replacement elbow is stainless, and not cast as is the original. 300 or 400 for new part if I am remembering correctly.
Rebel112r is offline   Reply With Quote
Old 05-09-2017, 07:10 PM   #8
Guru
 
Rebel112r's Avatar
 
City: Birch bay wa
Country: USA
Vessel Name: Rogue
Vessel Model: North Pacific 42
Join Date: Feb 2013
Posts: 561
Oops, didn't see last post.
Rebel112r is offline   Reply With Quote
Old 05-20-2017, 06:55 PM   #9
Senior Member
 
Islanddreamer's Avatar
 
City: Kingsville, MD
Country: USA
Vessel Name: Harmony
Vessel Model: Pacemaker 1990 37' Convertible
Join Date: Mar 2016
Posts: 285
Generator heat exchange failure?

OK so I have to re-ignite this post again. Problem came back. There is only one correct way to put the HX in, and after 3-4 removals, re installations, I need to go back and check the exhaust elbow.

Here is my question- the generator - although an older installation only has 198 hours on it overall. Is it possible for a generator with this low number of hours to have a plugged exhaust elbow?

Incidentally it has had a full five minutes of use this season to run my Keurig while away from the dock. Sheesh.
__________________
Any day aboard is a good day.
Islanddreamer is offline   Reply With Quote
Old 05-20-2017, 11:20 PM   #10
Guru
 
twistedtree's Avatar
 
City: Gloucester, MA
Country: USA
Join Date: Jan 2013
Posts: 4,949
Quote:
Originally Posted by Islanddreamer View Post

Here is my question- the generator - although an older installation only has 198 hours on it overall. Is it possible for a generator with this low number of hours to have a plugged exhaust elbow?
Yes, it is a distinct possibility.
__________________
www.MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 05-21-2017, 10:23 AM   #11
Guru
 
Rebel112r's Avatar
 
City: Birch bay wa
Country: USA
Vessel Name: Rogue
Vessel Model: North Pacific 42
Join Date: Feb 2013
Posts: 561
This is what I changed. I think the price has come down, to less than 300 bucks.
Attached Thumbnails
Click image for larger version

Name:	IMG_0327.JPG
Views:	43
Size:	56.6 KB
ID:	64957  
Rebel112r is offline   Reply With Quote
Old 05-21-2017, 05:27 PM   #12
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 7,925
Quote:
Originally Posted by Islanddreamer View Post
...Here is my question- the generator - although an older installation only has 198 hours on it overall. Is it possible for a generator with this low number of hours to have a plugged exhaust elbow?...
Quote:
Originally Posted by twistedtree View Post
Yes, it is a distinct possibility.
Yes. We had the same generator. The cast iron exhaust elbows on this model, in my opinion, is a major weak link. They are a maintenance item. We had one fail in less than 200 hours also. We changed to an after market stainless steel replacement and never regretted it.
Larry M is offline   Reply With Quote
Old 05-22-2017, 11:29 AM   #13
Veteran Member
 
pacopico's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: REEL INN
Vessel Model: Chris Craft Commander 36 Tournament Fisherman
Join Date: May 2016
Posts: 47
The number 1 cause of premature failure of a wet exhaust elbow due to "plugging" is lightly loading the genset.

Running for a few moments to make coffee and not loading it up is a no-no!
pacopico is offline   Reply With Quote
Old 05-23-2017, 10:09 AM   #14
Senior Member
 
Islanddreamer's Avatar
 
City: Kingsville, MD
Country: USA
Vessel Name: Harmony
Vessel Model: Pacemaker 1990 37' Convertible
Join Date: Mar 2016
Posts: 285
Generator heat exchange failure?

Yup- I have a diesel gen for the house too, and normally I run it with a ton of things operating.

We've really not used it that much at all as we are recreational boaters for now as I still work, but I don't want to have a system onboard that isn't properly functional. Thanks for the exhaust elbow help- later this week I'm going to pull it off. Latest price on this part isn't too bad either.
__________________

__________________
Any day aboard is a good day.
Islanddreamer is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 05:30 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×