I think you need a new or overhauled turbo. Obviously the turbo is not delivering the required air to burn the fuel that is squirted into your cylinders; that is why you get black smoke.
I was trained as a marine engineer and overhauled my share of turbo's. We used to take them apart, soak them (housing and turbine wheels including shaft but not the bearings) in carbon solvent (would be a no no in these days) and reinstall them with new bearings (which came ultra clean in sealed cans supplied by Brown Boveri) and seals. After that they would be OK for the next 10.000 hours. I am talking about turbo's with diameters of 1 up to 6 feet for the real marine engines here. The turbo's on Yanmar diesels are a lot smaller, rotate really fast (100 - 200 k rpm) and have super sensitive bearings and seals. My guess is the carb cleaner or foreign matter ruined the bearings.
Good luck with your troubles; I really understand your frustration.
Last edited by sigmasailor; 01-24-2010 at 05:59 AM.