Engine Trouble weed eater 25cc engine runs on choke

Hello just finished my first build. friction drive weed eater bike with a peg roller. only runs when I switch the carb between half and full choke. I have black residue exiting the muffler and on top of the sparkplug. too much oil? carb rebuild? thanks for the help in advance.

That black residue will be your carbon build up. Had you done a carb clean before you tried to fire er up? I'll clean everything before I put it all back together and fire it up for the first time IN MY HANDS. Sounds like the mixture is running lean if it only runs with the choke. A carb clean will go a long way. I'd start there if I was you.... I'm sure others will chime in.