Soot in the engine compartment

Ted

Ted

.
Jan 26, 2005
1,272
C&C 110 Bay Shore, Long Island, NY
The problem: Light coating of soot in the engine compartment after a 20 minute trip at about 2800 rpms.
The engine: Yanmar 2GM
The question: Where could it be coming from if the exhaust manifold gasket, exhaust manifold, mixing elbow and exhaust hose that connects to the wet exhaust muffler all check out OK?

It is not water pump/alternator belt dust. It happened is a very short period of time. The engine ran fine the entire time. Are there any other sources where soot could have exited the engine?
 
Ken13559

Ken13559

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Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Air intake could put out exhaust carbon if mixing elbow choke, V-belt wears, Exhaust elbow leaks .....
 
Ralph Johnstone

Ralph Johnstone

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Jan 4, 2006
7,276
Hunter 310 West Vancouver, B.C.
You certainly don't make it any easier by listing all the thing you've already checked. Leaves nothing on which to speculate or navel gaze.

Only other impossible place I can see it coming from is a huge blowby coming from your breather tube. This would be more than your air intake can suck in which is getting into the twilight zone. Have you noticed any rings being spit out the exhaust ?

Looking at this from a more practical point of view, can you open the engine cover when the engine is running and CAREFULLY inspect the engine for exhaust leaks ?

Dreadlocks and neckties are not appropriate wear for this inspection.
 
Chris Patterson

Chris Patterson

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Oct 17, 2011
2,809
Ericson 29 Southport..
Oh HELL no Ralph. If you have dreadlocks, I recommend doing it with no restraints. In fact, I would pay a hundred bucks to see it..
 
Rich Stidger

Rich Stidger

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Feb 10, 2004
4,142
Hunter 40.5 Warwick, RI
FWIW, I had the same issue with my Westerbeke genset. The source was a small hole in the underside of the exhaust elbow. Not easily visible, but you could feel the exhaust pressure.
 
Ted

Ted

.
Jan 26, 2005
1,272
C&C 110 Bay Shore, Long Island, NY
Found the problem early this morning. Actually I didn't notice a crack in the exhaust manifold upon initial inspection yesterday. It was hidden behind a piece of flaking cast iron from the manifold. I chipped it off and noticed a small 1/2" long crack where the joint connects the manifold and mixing elbow.

Next question. Does anyone know of a putty like product that would withstand the high temperatures of the exhaust manifold so that I can make a temporary repair. I have a race on Tuesday night that I don't want to miss and I don't expect to receive the new manifold for a few days. :cussing:
 
S

Steve Walsh

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Oct 6, 2009
129
Newport Newport 28 MKII Jacksonville, FL
I fixed a longer crack on a Fiat Spider convertible exhaust manifold with JB Weld. It was still holding after 3-4 years when I sold it, probably put 15,000 miles on the repair. And it is grey.
 
jibes138

jibes138

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Jan 27, 2008
3,086
ODay 35 Beaufort, NC
Back in the old days we would take a tin can and slice it length wise then use two hose clamps to hold the exhaust pipes together on our cars. If you used some fiberglass tape like they use to insulate the exhaust under the can it would probably seal it enough to not give you the soot.

WARNING!!! An exhaust leak means you are filling your boat with CARBON MONOXIDE. You will not see it, you will not smell it, you will just become disoriented, lose your ability to reason, then you will get sleepy and you will DIE. Worse one of your crew will die and you will live.

Make sure you have a working CO detector if you really do this and keep all hatches and ports open. I have seen people die from CO and it is not pretty.
 
DougM

DougM

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Jul 24, 2005
2,242
Beneteau 323 Manistee, MI
There was a product sold once upon a time called a "muffler bandage" in auto supply stores, It looked like a resin impregnated piece of fiberglass cloth.
It could be wrapped around a muffler with a hole in it and the head would form it into a solid repair. I don't know if it is even still available. It would certainly work fora short term temporary repair.
 
Ted

Ted

.
Jan 26, 2005
1,272
C&C 110 Bay Shore, Long Island, NY
I was thinking about using Marine Tex or JB Weld but was wondering if they world hold up to the high temperature at the exhaust manifold. Any ideas as to how hot it might get running for 5 minutes?

I will certainly be aware of the carbon monoxide issue. Although it's a very small crack, I will be sure there is plenty of ventilation and nobody would be allowed in the cabin. If it looks like the temp repair isn't working I'll have a fellow racer tow me to the start line. That "Good Guy Tow" demonstrating good sportsmanship should be good for another 6 second a mile.
 
Davidasailor26

Davidasailor26

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May 17, 2004
5,698
Beneteau Oceanis 37 Havre de Grace
DougM said:
There was a product sold once upon a time called a "muffler bandage" in auto supply stores, It looked like a resin impregnated piece of fiberglass cloth. It could be wrapped around a muffler with a hole in it and the head would form it into a solid repair. I don't know if it is even still available. It would certainly work fora short term temporary repair.
Click to expand
We got something like that from an auto store for a split in our exhaust elbow. Worked perfectly for several years until the elbow failed in a different place and needed replacing. Your mileage may vary, and as others have pointed out beware of the risks of any continuing exhaust gas leaks.
 
F

Fred Villiard

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Dec 28, 2009
397
Macgregor M25 trailer
Try furnace cement, it is made to repair very hot castings, should be able to find it at any hardware store.
 
Rich Stidger

Rich Stidger

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Feb 10, 2004
4,142
Hunter 40.5 Warwick, RI
I used JB Weld to do a temporary repair on my elbow. It is a 2-part epoxy that the package claims high temp manifold application. The repair looked so good I think it would have lasted forever. I did replace the bad part though.
 
RichH

RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Ted said:
Found the problem early this morning. Actually I didn't notice a crack in the exhaust manifold upon initial inspection yesterday. It was hidden behind a piece of flaking cast iron from the manifold. I chipped it off and noticed a small 1/2" long crack where the joint connects the manifold and mixing elbow.

Next question. Does anyone know of a putty like product that would withstand the high temperatures of the exhaust manifold so that I can make a temporary repair. I have a race on Tuesday night that I don't want to miss and I don't expect to receive the new manifold for a few days. :cussing:
Click to expand
Go to an auto supply store and get some "muffler cement" ... PUSH it into the crack. This is only a temporary repair.
 
Gunni

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Rich Stidger said:
I used JB Weld to do a temporary repair on my elbow. It is a 2-part epoxy that the package claims high temp manifold application. The repair looked so good I think it would have lasted forever. I did replace the bad part though.
Click to expand
I kept a Brit exhaust manifold running for years with JB weld. No worries with the heat. Wire brush the crack, and spread it on. Replace the part soon, CO hazard.
 
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