The reasons why Weichai generators emit black smoke are:
Possibly 1. The fuel injector is clogged with carbon deposits and the needle is blocked. 2. Overload, 3. Fuel injection is too late and part of the fuel is burned during the exhaust process. 4. Poor valve clearance and valve seal. 5. Uneven fuel supply to each cylinder of the fuel injection pump. 6. Intake pipe, blocked air filter, poor air intake, etc. Check the above 6 items carefully. I hope that will be the case. will be useful to you!