I've got a new filter for my Autolite 4100. It does not have tapered threads, which leads me to believe that a seal is formed through mechanical force, and that no thread sealant would be needed. Is this correct? Should I tighten this any more than hand tight?
The 4100 (and 2100) used two different filters, depending upon when they were made. The later ones had tapered pipe thread, but the earlier units had an inverted flare connection. The inverted flare should not be installed with thread sealer, since the threads do not seal the connection.
The carb inlet certainly looks like inverted flare (like this: http://www.wholesalecompressorparts.com/images/CTG.gif). The filter (1/2" UNF threads) screws in nicely while 1/4" NPT does not. I'm guessing it's inverted flare.