1980.  I could not get the new Neutral Safety Switch to align, so I connected the starter wire directly (yellow and purple). But, now the electric choke doesn't work.  Coincidence or is it somehow wired through the NSS?  Also, I have Magnaflow pipes, which are nice and throaty, but the fumes are excessive.  Can I attach Catalytic converters to the system and will that help?  

Check to see if the choke spring (coil) is broke.