If you have an NPT type fitting that is leaking, you have a few options
1 just try tightening the fitting.
2 take it apart, clean and inspect the threads on both parts, use teflon tape on the male threads, two wraps of the tape in the direction that will not unwind the tape as the fitting is inserted. If applied correctly, it will not get in the fuel system. The tape ends up inbetween the threads and stays there.
3 replace the fittings.
good luck