Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 19-06-2019, 18:01   #1
Registered User

Join Date: Jun 2019
Posts: 6
Yanmar Exhaust Elbow - Source of leak?

Hello,


Long time lurker, finally posting. Running into an issue with an exhaust elbow for a Yanmar 2GM20F that I could use some input on.



I replaced the exhaust riser, coupling, and exhaust elbow at the beginning of last season as the old one had reached the end of its lifespan. Everything ran great last summer through winterization. Fast forward to this season, replaced the impeller, recommissioned the engine, and everything looked fine again. However, now I am getting a small leak at the coupler junction (the double threaded piece that connects the riser to the elbow).



Thoughts on where is the water coming from?



In theory, there shouldn't be any water at that junction, just exhaust. Water is coming out the exhaust at the transom as expected. I pulled everything off to have a look and the elbow looks fine, no cracks/holes. I put it back together with Hercules Real-Tuff teflon thread sealant (hand tightened with a 90 degree bend), put it back on and still same issue. The engine appears to be running fineI am wondering if there might be some sort of blockage in the wet exhaust hose further down stream but then why would water still be coming out? I could run a snake from the muffler back to see if there is any thing in there.


Any thoughts would be greatly appreciated. Thanks in advance.
__________________

bostonbubba is offline   Reply With Quote
Old 20-06-2019, 03:07   #2
Senior Cruiser
 
GordMay's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 35,341
Images: 241
Re: Yanmar Exhaust Elbow - Source of leak?

Greetings and welcome aboard the CF, Bubba.
__________________

__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is online now   Reply With Quote
Old 20-06-2019, 04:26   #3
sitting on the dock of the bay

Join Date: Mar 2006
Location: somewhere in the south
Posts: 1,767
Images: 6
Send a message via Yahoo to gonesail
Re: Yanmar Exhaust Elbow - Source of leak?

not an expert but I would assume the joint is not tightened enough. also Yanmar warns against wrenching this joint while it is still connected to the manifold.
__________________
some of the best times of my life were spent on a boat. it just took a long time to realize it

gonesail is offline   Reply With Quote
Old 20-06-2019, 06:31   #4
Registered User

Join Date: Jun 2019
Posts: 6
Re: Yanmar Exhaust Elbow - Source of leak?

gonesail - thanks for the reply and input. I had hand tightened it with the whole thing pulled off the engine. I will give it another try and see if I can tighten the top portion of the coupler/elbow a bit more.
bostonbubba is offline   Reply With Quote
Old 20-06-2019, 08:50   #5
Registered User

Join Date: Feb 2011
Posts: 80
Re: Yanmar Exhaust Elbow - Source of leak?

i replaced my exhaust elbow a few years ago (3gm30). If I remember correctly, that nipple has reverse threads on one end. This allows you to simply tighten it up a bit will everything is still hooked up.

In other words, you don't have to take off the exhaust hose and work backwards.

I would, however, be careful not to apply too much force when tightening. Use a pipe wrench and go easy. You surely don't want to damage the exhaust manifold.
bratzcpa is offline   Reply With Quote
Old 20-06-2019, 09:21   #6
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 25,494
Re: Yanmar Exhaust Elbow - Source of leak?

I think I would call Mack Boring or another good, reputable Yanmar dealer and ask a mechanic, cause if I understand, the issue isn't why is it leaking so much, as why is there water, where there shouldn't be?

I'd want an answer to that before I ended up with a hydrolocked motor
a64pilot is offline   Reply With Quote
Old 20-06-2019, 09:30   #7
Registered User

Join Date: Jun 2019
Posts: 6
Re: Yanmar Exhaust Elbow - Source of leak?

a64pilot - I am thinking along the same lines. If I am understanding the internals of the elbow correctly, not sure how water would get from the sea water inlet down into the hot exhaust inlet (exhaust and water inlet are two separate chambers that meet at the cooled exhaust outlet). Maybe there is a hairline crack in the elbow somewhere. More investigation is warranted.



Thanks for the info.
bostonbubba is offline   Reply With Quote
Old 20-06-2019, 10:05   #8
Registered User

Join Date: Nov 2017
Posts: 42
Re: Yanmar Exhaust Elbow - Source of leak?

It's a wet exhaust, water flows through the manifold and that is the mixing elbow elbow. the Yanmar shop I use gets a kit that includes the entire assy, the manifold and elbow, preassembled. they told me that connection can be a bit problematic to seal so they just replace the entire setup. you may have to take it apart and use sealant on thethreads.
Tusitala is offline   Reply With Quote
Old 20-06-2019, 13:23   #9
Moderator
 
roverhi's Avatar

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,722
Send a message via Yahoo to roverhi
Re: Yanmar Exhaust Elbow - Source of leak?

Quote:
Originally Posted by bostonbubba View Post
gonesail - thanks for the reply and input. I had hand tightened it with the whole thing pulled off the engine. I will give it another try and see if I can tighten the top portion of the coupler/elbow a bit more.
What is HAND tightened?? Should have used a pipe wrench with the assembly held in a good vice. Pipe threads require a goodly amount of torque to be sure that you get a seal. Think the reason than Yanmar says not to assemble disassemble in place because of the torque on the exhaust riser needed to ensure a seal. Getting it apart is another story. Tried changing mine with two large pipe wrenches, cheater bar, and a friend helping without success. Had to call in the Calvary that game with a humongous vice, torch, even bigger pipe wrench with cheater bar and it was still a bitch to get apart.
__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
roverhi is offline   Reply With Quote
Old 21-06-2019, 02:37   #10
Registered User

Join Date: Jun 2019
Posts: 6
Re: Yanmar Exhaust Elbow - Source of leak?

roverhi - thanks for the input. When fully tightened, the exhaust riser and elbow are at 180 degrees (straight line). I need a 90 degree bend so either side of the coupling won't be fully tight when at 90 degrees. My guess is that I haven't used enough "goop" on the threads and I haven't tightened it enough. Will try both.
bostonbubba is offline   Reply With Quote
Old 21-06-2019, 04:23   #11
Registered User
 
AA3JY's Avatar

Join Date: Jan 2013
Location: Kimberton,Pa.
Boat: Cabo Rico 34
Posts: 133
Re: Yanmar Exhaust Elbow - Source of leak?

We replaced our Yanmar exhaust elbow with one of these..

https://hdimarine.net/product/gm-sta...-mixing-elbow/
AA3JY is offline   Reply With Quote
Old 21-06-2019, 04:54   #12
Registered User

Join Date: Aug 2016
Location: Long Island, NY
Boat: Cal 33-2
Posts: 161
Re: Yanmar Exhaust Elbow - Source of leak?

Quote:
Originally Posted by bratzcpa View Post
i replaced my exhaust elbow a few years ago (3gm30). If I remember correctly, that nipple has reverse threads on one end. This allows you to simply tighten it up a bit will everything is still hooked up.

In other words, you don't have to take off the exhaust hose and work backwards.

I would, however, be careful not to apply too much force when tightening. Use a pipe wrench and go easy. You surely don't want to damage the exhaust manifold.
On my 3GM30F there is a coupling that has right hand threads on one end and left hand threads on the other. This allows tightening with the elbow at any angle and without need to rotate the elbow. Just turn the hex on the coupling.
__________________
S/V First Tracks
1985 Cal 33-2
JimsCAL is offline   Reply With Quote
Old 21-06-2019, 05:33   #13
Registered User

Join Date: Oct 2010
Location: The boat - New Bern, NC, USA; Us - Kingsport, TN, USA
Boat: 1988 Pacific Seacraft 34
Posts: 691
Re: Yanmar Exhaust Elbow - Source of leak?

But, I still don't understand why the OP has water on the inlet side of the Yanmar exhaust elbow. The elbow is designed so that the water injected into the elbow goes out the outlet of the elbow.

Other than the initial condensation of water vapor in the exhaust on cold metal before everything heats up, why is liquid water in the left-hand/right-hand threaded nipple that is on the inlet side?
wsmurdoch is online now   Reply With Quote
Old 21-06-2019, 07:12   #14
Registered User

Join Date: Jun 2019
Posts: 6
Re: Yanmar Exhaust Elbow - Source of leak?

AA3JY - I have the exact same one except I got the riser as well (HDI sells a kit)


JimsCAL - I tried that but one half is always not at full tightness. When I asked HDI if the could tighten prior to shipping, they said they could only tighten it straight.


In poking around the interwebs, I found this article that seems to suggest the same thing:


The opposing threads on the connector are supposed to draw the two elbows together as its tightened, but I found that the mixing elbow was about a quarter-turn adrift of its optimum position after the riser was snugged tight. A healthy glob of high-temperature exhaust sealant was applied to the threads, and the assembly was left overnight to dry. It had set rock hard by the morning.


https://www.sailmagazine.com/diy/mai...diesel-exhaust
bostonbubba is offline   Reply With Quote
Old 21-06-2019, 07:26   #15
Registered User

Join Date: Jun 2019
Posts: 6
Re: Yanmar Exhaust Elbow - Source of leak?

wsmurdoch - when I noticed the leak, the engine maybe had only been running for a couple of minutes. The elbow was warm but not hot. Not sure how long it would need to run to burn off the initial condensation.
__________________

bostonbubba is offline   Reply With Quote
Reply

Tags
elbow, exhaust, yanmar

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 2GM20F Exhaust Mixer/Elbow kiltym Engines and Propulsion Systems 37 16-02-2017 17:58
Exhaust elbow for Yanmar 3jH2-TE DevlinMike Engines and Propulsion Systems 0 18-09-2014 10:37
[SOLD] Yanmar Exhaust Mixer Elbow SailorHarry Classifieds Archive 5 08-06-2012 14:12
Yanmar OEM Exhaust Elbow or After-Market ? zippy Engines and Propulsion Systems 8 26-07-2011 05:36
Yanmar 1GM10 Exhaust Elbow and Carbon troppo Engines and Propulsion Systems 9 13-12-2010 06:23



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:19.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.