Briggs & Stratton Choke ... Broke?

I have an older self propelled B&S 3.5hp that has a choke control. It broke and I'm trying to put it back together. I noticed that the choke controls a butterfly for the starter cup. I'm assuming that this is broken as the butterfly stays open constantly and there is no spring or wire attached to it. What do I need to do/buy to fix?

Also, should fixing this help get fuel to the carb? It seems from the starter cup, the gas flows behind the air filter and into the carb area... As of right now I can only start the mower when I put gas directly into the carb.

Thanks!