First time mods on my 318 and it won't start...

You need a real "carburetor cleaner." Chemicals have become "greener" over the years, so I don't know anymore what brand works. Last I "figured" Gunk is not worth dragging home, "Mechanics brand" used to be good. Also get some good carb spray cleaner, and wear eye protection. Use the snorkel to blow out every tiny passage you can find Be careful blowing out with air that you don't unseat some core plug or blow EG the accel pump needle/ ball out to "yonder pasture."

Berryman chem dip and Gumout if you can find either are good "dip" also