Fuel pump question

[NoviceM]

My fuel pump is fine (1970 travelor) but I have a spare pump so I thought I would fit that temporarily to check that it worked for use sometime in the future.
It works fine.....with one issue....when engine has been running...swith off ignition to stop the engine. When ignition is switched back on, but without starting engine.....the pump continues to tick at about one second intervals, even though fuel is not being consumed by carb. There are no visible leaks of petrol.
Question, a) what might be causing it and b) does it matter?
Just being a bit 'obsessive' given that petrol us involved.
Any info, welcome

[geoberni]

Most likely general wear and tear, aka old age, means that the one-way valves, which are simply a metal discs, are allowing the pressure build up to leak back past one or both of them. Probably the 'inlet' allowing fuel to leak back past it to the incoming feed.
It could just be a bit of dirt/debris in there (although it is after the built in filter), take it apart and see how clean it looks. It might need overhaul.

All cars tend to click a bit when turned back on, I take it this one is doing it far more than your other pump did?

SU valve.JPG (85.43 KiB) Viewed 1163 times

[geoberni]

If only people would come back and conclude the topic, or at least acknowledge the response.....