black smoke and black crud in the water

[joe phibbs]

We have a problem with the Yanmar 2GM30F on our Hunter 1986 31:In November ALURE became hard to start and put out billious black smoke. We (eventually) replaced the Mixing U, Coupler and manifold mounting. We checked the air filter and fuel filter(s). All seemed well, but troubles returned: She is still hard to start but runs well up to 2800 rpm under load tied to the pier. But when we run up to our maximum 3000, the smoke (grayish) and black crud starts again. Any ideas, you all?

 

[Pete]

check for air leak in fuel system

Check the ENTIRE fuel system sounds like you have air in the system. could be anything from a fuel line fitting to a injector washer leaking air.You may not see fuel leaking as it could be sucking air into the system,these leaks can be very hard to find and very frustrating. You might also want to check the valve adjustment.Good Luck !

 

[matt]

Pete is right - check everything

I had the exact problem you describe in the past month - lots of smoke indeed. I went over everything, checking the elbow, manifold, air filter, all of the diesel filters....and what did it turn out to be? The fuel line had a slight tear or crack at the tank side of the fuel pump allowing air into the line. Once I cut off the end, put EVERYTHING back together, including that pesky fuel line, and got the thing started, it went right over 3000 rpm w/o issue under load and the smoke disappeared... I ran it hard again last weekend just to be sure it was indeed fixed, and everything is fine.... Hope this helps. Btw, mine is a 3GM30F as well...good luck,matt

 

[Mick]

black smoke

I HAVEN'T SEEN ANYONE TELL YOU TO CHANGE YOUR FUEL FILTERS. DO THIS NOW AND TELL US WHAT HAPPENS. IF YOU USE BIODIESEL YOU WON'T HAVE ANY BLACK SMOKE PROBLEMS. BUT IF THE ENGINE'S BROKE THEN IT DOESN'T MATTER. CHECK YOUR FILTERS