Fuel pump and carb vehicle questions
 

I have a Nissan 1400 ute, same platform as the Datsun 1200 UTE with the a14 carb engine.

My manual fuel pump packed up a few weeks ago and as a quick fix I added a low pressure electronic fuel pump, would the electronic fuel pump make it heavier on fuel or will the excess fuel just pump back into the tank via the return pipe?

Then another question, while idling at a traffic light, eg for 30 seconds or longer, I have judged more or less which lights on my route take how long before they change and most are 45 seconds or longer, would turning the engine off and restarting when the its time to go again help with fuel efficiency, the vehicle has no start up issues. Ive heard that a carburetor uses more fuel to start than to idle for a short period.

The only way the fuel pump would dump more fuel into the engine is if it was set to a higher pressure than the last one and that fuel pressure can over power the needle valves held closes by the floats.

Do one better if you know the light is going to turn red, or as you come to a stop sigh turn the engine off before you stop.
I'm guessing you have a manual transmission?
It only uses more fuel on a cold start with the choke.

Yes its a manual and I give the coasting to a stop with the engine off a go. Don't think ive ever needed to use the choke to start it to be honest, maybe really cold winter days but generally has no issues starting up.