Is it possible to make more energy that was used for?
Can the combination electric boiler - steam engine work infinity long?

NO
unless you use moded turbined or steam engines there will allways be a loss

also the efficiency was posted all the time , mk4 is 95% so close to a loop but still at a loss over time

what part of the code would need to be changed to make one generate a positive loop asking for my own use

https://wiki.factorio.com/Console
For instance, here's a stack of the god-mode energy system interface:
(Type to console:)

        /c game.player.insert{name="electric-energy-interface"}

@eru increase efficiency over 1

lines:
67
516
959
1407

ty