Previously I had a serious fuel leakage from the carburettor (Spaco 20/20). I've replaced the float needle and it's finally gone.
I adjusted the screws (idle and mixture) to the original setting I've been using without any problems. After that I made a test ride. First, everything was OK then things changed. Engine got weak and misfiring at high rev. The plug turned black. I tried to adjust the mixture screw to give it a bit lean but after that it can't start until now whatever setting I try. I suspect that fuel level is still too high despite it's not flooding. I even removed the air filter to expose the air intake but it still doesn't start.
What are your suggestions?