Re: Fuel filters
The threads in the kit tank are not 3/8". It is a metric machine thread but it can be modified with a 1/8" pipe tap. Be very careful and don't thread too deep, just enough so a 1/8" male fitting will start good. Let the tapered threads do the sealing. If you have any seapage, SealAll will stop it.
As for fuel line, I'm not sure how you guys are getting 3/16" I.D tubing to fit over the petcock/carburetor barbed nipples. I use 1/4" I.D (inside diameter) fuel line and it does fine even without clamps, but I do clamp them just for security.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"