I'm new to diesel, so I'm not sure if this is normal. At start up, the waterlift muffler ejected probably a couple teaspoons of dense oil. It had been sitting for week. Seems to run fine with no other issues, always starts right up. Should this be something to be concerned about? See photo.
It didn't dissipate into a rainbow like a normal fuel spill, it remained in dense black blobs.
M25XP
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Hummina
1987 Catalina 36 MKI
#741
Bayfield, WI. Usually.
I am pretty god at gasoline engines but new to diesels but I would guess this is not normal. My boat has a M35-B engine installed that is about 14 years old and when I start it I seldom even get a puff of smoke. I would try a compression test and see if oil is blowing past the piston rings - just a guess.
Peder Sahlin
Pompano Beach, FL
1983 - C36 Standard Rig / Wing Keel
Hull #103
This is unburned fuel. It is accumulated in the wet exhaust pipe and is blown out when you first start the engine. Basically the fuel is too rich and is not completely burned, it is sooth. This can happen if you idle for a long time at low RPM. Try running the engine at 2000 RPM or higher for 15 minutes. I would not be too concerned about it. My M35B does that from time to time and it runs just fine.
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
This is NORMAL!
What happens in a muffler?
It MIXES the exhaust GASES (think of the cr*p that's in there!) with the water. If it's been sitting for a day a week or a month or an hour, it's gonna be some DIRTY stuff.
My advice: get used to it.
Good luck. :)
My avatar picture, for some bizarre reason, is of my new exhaust riser, somewhat different than yours, but the identical concept. Gases IN, mixes with the HX water output at the nipple, and goes into the muffler. Right?
It has NOTHING to do with fuel. Or shouldn't.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
At shutdown, some exhaust elements are just not going to make it all the way out and will settle on the walls of your hose and much of this will drain back into the muffler. Just for fun, here's the list of things you'll find in your diesel exhaust. Not listed is the sea water and the science experiment that begins inside your wet exhaust system once it stops moving:
STANDARD DIESEL
Carbon dioxide
Carbon monoxide
Nitrogen dioxide
Nitric oxide
Sulfur dioxide
DEPENDING ON THE SOURCE, BIODIESEL MAY HAVE THE FOLLOWING:
Acrolein
o-Anisaldehyde
Benzene
2,3-Benzofuran
Coumarin
Formaldehyde
4-Hydroxycoumarin
m-Hydroxyacetophenone
2-Hydroxy-4-methoxyacetophenone
Menadione
6-Methoxytetralone
6-Methylcoumarin
3-Methyl-2-cyclopentene-2-ol-one
Trimethylbenzene (mixed isomers)
Polynuclear aromatic hydrocarbons
Nick Caballero
Retired C36/375IA Mk II Technical Editor
Feeling MUCH better now. Especially for the list newguy!
Hummina
1987 Catalina 36 MKI
#741
Bayfield, WI. Usually.
We've all been the list newguy at one point. :-)
Ben Ethridge
Miami, FL
1984 MK1 Hull# 263