The annoying black plastic screw wich holds the whole essambly in place, yes that's the one. Mine was very easy to unscrew. I took a file, put it on the notches and banged on with a hammer. When it got going the rest was a handjob. When banging the file, some body remainded me about the gasoline fumes and my hair stod on the end. But fortunately the file handle was of palstic and the screw also. I'v never seen sparks coming from that material. Still, be carefull with the fumes, there could be hell of a explosion.