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Re: Bukh DV10 Slow Throttle & Black Exhaust smoke
My first impression of your symptoms was injecter pump timing. I was thinking you might have a worn out timing chain. When they jump a tooth you loose power and acceleration is slow with lots of black smoke. Generally if and when it jumps another tooth the Pistons will contact the valves bending them or breaking the valve causing severe engine damage. A slack timing chain can be checked by pulling an injector and rotating the crank until the piston is at top dead center, insert a small plastic stir straw into the injector hole to see when the piston moves up and down. Rotate the crank left and right and you will be able to feel the slack in the chain. 6-8 degrees is about the limit of rotation you should see. Over that I would replace the chain and gears. The other, absolute method is to remove the timing chain cover and check to see if the marks are aligned property as well as the injector pump gear.
The second thing to consider is an injector stuck open. This will cause a slow throttle response, lots of black smoke. This condition with also burn and melt the top of the piston, a hydrolock may occur and blow a head gasket, break piston rings and bend piston rods and valves. Glad you got it worked out. If none of the above is the case you should be able to drive it like you stole it. Good luck.