Stubborn starting question...

The above is good, because it checks the linkage, but you can also check the choke pull off after the engine is running. All the time the engine runs, the pull off should be "sucked" in. You can unhook the vacuum line to the pulloff, hook it back up, and watch it "suck in" if it's working.

Also look for sticking linkage parts, bent, stuck, corroded, gummed up, etc.