PLEASE HELP My Brother downshifted at high-speed and now it won't pullstart

[Busboy]

So yesterday I rebuilt the carb on my honda 185s and let me brother go for a ride. He said all he did was down shift going pretty fast in 3rd. The 3wheeler died and now I can't get it to start at all. I have no idea where to start....

Edit..... only starts with the choke wide open and holding the throttle while I pull start it. As soon as I let off throttle it dies. I'm new to these machines and carbs so any help is greatly appreciated