2QM15 Black Soot

[Martin Grant]

On start up my Yanmar 2QM15 deposits what appears to be Black soot in the water (not very nice) could be carbon but am unsure does anyone know out there what this could be? a valve perhaps not seating right or a blocked injector any ideas, hope anybody on the list that had there boat moored in the Hurricane area survived Ok. Thanks again for the helpMartin Grant

 

[Don Berger]

could be

any number of things.My son's boat had the same problem which isn't to say your solution would be similar. In his case, he started with the easy (read- cheaper) alternatives beginning with a bad injector and plugged exhaust elbow. He did both but believes the problem was the elbow. Regardless, in that case, it fixed the sooty exhaust. Should mentiopn he had new fuel and filters already and good compression.Don

 

[Andy]

Clogged Injectors

Sounds like injector tips could use replacing. They may be "breaking" (compression point at which they spray fuel)too soon. But before you replace the nozzles, make sure your fuel filters a clean and the fuel is good. You might want to run some fuel conditioner through the injectors to see if that will clean them up.

 

[Dave]

black soot

Martin,I had similar problem. It turned out to be the fact that the effectiveness of my bottom paint had run it's course, and the marine growth was awesome. Also, the prop was pretty well fouled. I had black soot on startup but it got really bad when I tried to run at normal speed. When I checked some references on diesel operation, I found that overloading them causes severe smoking. A new bottom job cured everything.Another lesson learned - Don't leave a boat in the water for a whole summer in Florida without having the bottom cleaned regularly.Hope this helps.Dave...

 

[Jim]

fouled prop

i also had this problem when my prop got fouled by a bunch of seaweed once. ie a loading problem.