If any sealant is needed, use the Permatex fuel sealant that is brown. The other brands are brown as well. I use it to seal my intake gaskets and also the gaskets on my supercharger. Never have had any problems with it.

I thought mine was ok but there was a little damp spot on the concrete and my tank was empty. Then my favorite parts store manager said he no longer sold the regulator I used as he had many of them returned because of leaking. Then I started looking for a cause.

I use no sealant on my fuel lines and had no leaks.

The use of ethyl alcohol in fuel requires different thread sealants used because many common sealants are commonly diluted with alcohol.

In fact one gasketing compound has instructions to use rubbing alcohol to remove it. Permatex thread sealant lists ethyl alcohol as a main ingredient. That does not build my confidence in it.

I have used Locktite Hydraulic Thead Sealant with excellent results but as its price has doubled I'm looking for a cheaper alternative.

I thought I'd found it in teflon tape, but although the tape is inert, tiny threads of it get into the fuel causing problems.

There is one called Gasola which comes in different grades, some of which resist alcohol and gasoline.

Hylomar is both gasoline and alcohol resistant but it does not resist pressure. I have seen it come squirting out of oil line fittings once they warmed up. Then the oil came squirting out.