was just heading out gold coast seaway sat afternoon when I noticed black sooty water coming out of my exhaust on high revs going against the tide...on lowering the revs the problem was rectified, any ideas on the cause of the problem?
thank you for your input but my knowledge of engines is far from expert so could you please clarify when you mean mixture? I was of the understanding that diesel engines run on diesel and air? it is an old deautch 30 hp circa 1970-80
Hi, it's not easy finding straight advice on diesels engines. From my experience injectors need to be removed and cleaned by a diesel shop every 10 to 20 years for good running! A bench test is the only way and not some cleaner in a bottle, also make sure your engine reaches running temp. To burn efficiently. Mixture can be done on most engines however they are set in the workshop and rarely need doing. Removing injectors is an easy job with care! Don't force it and look for a suitable lever. The money saved in removing them yourself would pay for cleaning at the workshop, about $30 each last time I done it.
^^^^ Yep, if your prop is not clean it won't work as efficiently & you're trying to get the same revs/speed as when it was clean - it won't happen!!
On the way to the marina to get antifouled with a dirty prop & hull I could only get just over half the usual top speed no matter how much throttle - just black smoke belching out the more I tried. With a clean prop & hull it was all back to normal - no smoke & good revs & speed.
We had the same problem. Coming back from short trip. Suddenly the engine start blowing thick black smoke and lost the revs too. Taking to few diesel engine people. The one we ask to cure the problem, ordered to change to exhaust heat cooling unit. First you check if your exhaust system is not partly waterlocked. That's create overloading and smoke too. We didn't have to touch the engine, that was it.
I think I would pull the exhaust elbow first and clean the carbon build up, would be very surprised if there is none there. Reassemble and test. Cheers Rob.
My little yacht BMW diesel had not started for 12 months she was a bit hard to start but after some aero start and persistence she fired and ran but missed a few beats and wouldn't take any load when I put her in gear.....anyways my mind was thinking head gasket and salt water entering combustion chamber but I decided to start with the basic checks first before head gasket nightmare.
While the engine was running I traced fuel lines and drained water trap etc ......and to my suprise I seen a jet of fuel squirting from the hose clamp location on the primary filter! Shortend the hose removing the cut section of hose and presto she now runs again like a clock!
Ok so BMW runs like a clock out to my sail host location, 3 hour sail complete return to sail drop location start BMW. Blows black smoke and refuses to idle but still gets me back to the dock just!
Problem? What is the problem? Valve? Head? Fuel? ......a simple problem comes to thought.......check stop cable! Yes it was not fully returned to off position .....restart engine runs like clock! Relax and drink more cold beer!
when I noticed black sooty water coming out of my exhaust on high revs going against the tide
...on lowering the revs the problem was rectified, any ideas on the cause of the problem? 
