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Cam Wallis
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Joined: 1/31/21
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M25 leaking onto galley floor

G'day team
day two of boat ownership and here we go.
After a solid 4 hour motor from Long Beach to MDR on Thursday with no issue, we went for a brief twilight sail last night 20 mins of motor max.
When we got into the slip I found the engine was hot and there was black water over my galley floor.
I didn't check the temperature gauge as I was to busy cleaning up the spill.
I was planning on getting it serviced next week but this has just moved the timeline up.
any thoughts much appreciated.
Cheers 
Cam, Solasta

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Sojourn
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Posts: 63

Cam,

Just to make sure:  Did the water contain either oil or antifreeze?  Possibilities are a hose leak or a gasket leak.  If neither and just "black" water, the next possible answer is the muffler leaks.  The muffler is just behind the galley.  The black is the exhaust, maybe too much carbon, indicating some possible engine blow by.  The water is the mixture in the muffler used to cool the hot engine exhaust to allow it to safety be lead overboard.  

If the area around where the exhaust exits the boat has black streaks, it indicates you're burning crankcase oil caused by piston by-pass.  Check around the muffler and look for blacked residue, a sign of the muffler leaking.  Caused by hose damage or a crack in the muffler housing.

Hope this helps.

Lou Bruska
Sojourn
1985 C-36 MK1, hull 495

Cam Wallis
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Joined: 1/31/21
Posts: 4

Thanks so much Lou, I got to the bottom of it this morning and unfortunatly the exhust pipe has been sheared clean through see attached photo.
Love to get peoples thoughts on how big of a job this will be to replace or repair?

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Sojourn
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Cam,

Of itself it's not complicated, however, I would have it professionally done.  I had my engine replaced some years ago and watched the work.  Replacing the hose and properly wrapping the insulation and wire securing it, took some skill.  It is also a good time to inspect the entire exhaust system.

Lou

 

William Miller
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Joined: 10/4/08
Posts: 294

Its a pretty easy job and there is alot of info on this site about doing it

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Chachere
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Joined: 10/27/10
Posts: 730

Bummer that this happened so early in your ownership, but the riser is a "wear item" that one needs to inspect every so often and eventually replace. Hey - at least you are in your home port (we had ours go while 400 miles away from home during a vacation cruise, but luckily found a local marina with a workshop to help us build a new one).   

You have two main options: 
- Catalina Direct sells a nice stainless steel heat riser for around 5 "boat bucks" -- https://www.catalinadirect.com/shop-by-boat/catalina-36/engine/exhaust-system/exhaust-riser-c-36-wm-25-engine/
-  You can fabricate something yourself out of pipe nipples and plumbing fittings for around 1 "boat buck" (many use 1 1/4" black pipe and fittings; on my second rebuild I used 1 1/4" schedule 80 seamless stainless pipe and fittings, although I can't say whether it will last longer -- but 6 years later so far so good)

Here are some links to some of the threads discussing the rebuild/replacement, or just do a search on "exhaust riser" and you'd find plenty of prior write-ups:
https://www.catalina36.org/forum/technical-discussion/exhaust-riser-rebuild
https://www.catalina36.org/forum/technical-discussion/new-exhaust-riser-1-14-black-iron-pipe
https://www.catalina36.org/forum/technical-discussion/new-exhaust-riser
Some of those threads give materials dimensions, but given the variations in engines and locations of the waterlift muffler, I think there is probably no one-size-fits-all dimension, so you most likely need to do some of your own measurements to suit.
Good luck.

Cam Wallis
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Joined: 1/31/21
Posts: 4

Thank you so much to all of you.
What an amazing community we have here!
really appreciate it!
Cheers 
Cam, Solasta

Cam Wallis
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Posts: 4

Another question that came to mind that might be the cause of my gaping riser wound, how much should the engine vibrate at idle?
I noticed that mine was quite violently vibrating when I quickly started it up to test my theories on the damage to the exhaust riser. 

William Miller
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Joined: 10/4/08
Posts: 294

These engines are not smooth below 1000 rpm When shifting come back to idle but if in neurtal bring the rpms up till it smooths out

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Chachere
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The engine movement of course puts some stress on the exhaust riser.  As you'll read in the various threads linked in my prior email, one way to ameliorate this is to install a "hump hose" connector between the riser and the water-lift muffler, so that there is more ability to flex (if you don't already have one).   

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