You might need to put a new choke in !!
If yours is stock & has not been rebuilt, you could send it to Mountain Man Fuel Systems & let him make it like new again !! Like he did to this one !! For a little over $200 !!
That thing looks awesome and considering the cost/time to do it myself he looks worth every penny!!!
Does he un-cap the mixture screws?
On mine there is a sensor on top in a spot that looks capped on yours, is that sensor necessary?
This looks like the route I'm going when I'm ready but I'm gonna check with a friend here locally that rebuilt Rochesters for his first five years out of high school before making final decisions. He said he would do it for free if I buy that parts but I don't know if it will be as good of a job, I think the parts would cost more money as well.