JFK Terminal 8
 

Flying from LAX to FCO with plane change at JFK terminal 8. LAX-JFK arrive to terminal 8 and JFK-FCO departs from terminal 8. We have 1hr 45min for layover. Is this enough time, assuming incoming flight goes on time? I do not think we would have any security check between the flights and we do not have checked in luggage. Do we just walk from one gate to another? Thank you

Yes, you just walk from one gate to another.

Correct. As @J62 says, no problem as long as everything is on time. Your bags will be checked through all the way, so it's like changing at any other airport, with no additional security checks between a domestic arrival and an international departure.

Thank you for your replies.
How about on the way back from FCO to JFK and then on to LAX?
There is a passport control on entry and then re-entry to the terminal through security again?

Yes,correct.

I fly out of Terminal 8 fairly regularly. Compared to other terminals at JFK, the security lines are usually reasonable, but immigration and customs can be slow. While you have enough time on your trip to Rome, I'd rather see at least 3 hours between flights for the return.