Fuel pump with carbs, Should it run all the time? Options

[brooks944]

Hi, I have a 1.8 ( now 1911) with 40 Webers and Web cam. It has run rich and my local shop has changed jets and it was running strong. I am now having starting problems and it seems to smell like it’s rich again. Last time I drove it it backfired a couple of times under load and it sounded like the backfire was from the carbs(?). My main question is on the fuel pump, which is a faucet type from the local auto parts store. Should the pump run continuously or shut off when a certain pressure is reached? Mine runs all the time when the key is on. I don’t believe there is a fuel pressure regulator on now.
Thanks for your help on my issues,
Rick

[technicalninja]

pull main and idle jets, clean the piss out of them. Make sure the idle jets have good O-ring (bad about leaking air into idle fuel stream).

I use HBNR AC O-rings all the time, but I run an automotive AC shop...

Blown out jet ports with low pressure air (50psi).

Hold jets in front of light, you can see stuck crap this way.

Clean it all up good, re-assemble, verify secondary ignition is good (plugs wires, distributer cap/rotor. Looks for "carbon tracts" in cap/rotor.

Verify strong blue spark to each plug.

Go drive, popping still happening?

Compression test first and then leak down test.

Eliminate spark and fuel as the issue and it will come down to intake valve on the back firing cylinder will have poor seat contact.
Valve adjustment might fix it if too tight.

My 1st 914 was afflicted with this. It didn't backfire all the time but sometimes it would shoot flames from the center mount progressive carb badly.

One night, leaving a young ladies house at 3am, trying not to wake her parents, I set their tree on fire with that damn 914...