Diesel's will smoke a little more at start up since there is no boost, but they are trying to inject sufficient fuel to get it started. When diesels get close to stoichiometric they get smoky, which is ~14.5 air to fuel ratio for typical diesel fuel. The actual afr where visible smoke is noticed depends on the injector design, pressure, injection timing, charge air temp, charge air pressure, compression ratio, etc. For an unfiltered exhaust on a fully warm and boosted engine, the limit is typically in the 15-18 afr range for ~10-15% opacity (this opacity is roughly a small visible puff of smoke). The video appears to be closer to a ~100% opacity.
At low starting speed and idling, mechanical injection systems do not produce full injection pressures which can cause more smoke due to poorer atomization of the fuel.
I suspect that this is a 2-stroke (4-valve) diesel. In which case, it may not have efficient exhaust scavenging at start up with no boost, which hurts the afr.
Finally, this excessive amount of smoke may be due to ether injection at start up (even more fuel, closer to stoich or even excess fuel). Ether injection into the intake is a cold diesel starting aid.
Black smoke is soot and PM emissions. Soot and PM emissions are found to be carcinogenic.
