I know this is a much asked question. I work away from home a month at a time, so my 1987 Toyota pickup 2x4 sits till I return. It absolutely will not start without a very small shot of starting fluid in the breather. I just installed a NEW carburetor. Once it's starts it's fine as long as I don't let it sit more than 7-8 days. Truck runs smooth and strong.

 

Seems to be the Nature of gas these days.

It tends to evaporate while sitting for long periods of time .

or the fuel drains back to the tank when sitting that long.

Then the mechanical pump takes quite a while to get fuel to the carb.

Spray a shot of starting fluid to get it running your good to go.

Is the fuel pump helping make the issue worse who can say.

Don`t know how much a problem this is or what you want to do to fix it.

Just a thought a electric pump made for the psi of the Carb turn the key your fuel system is pressurized .

You may have other issues as well.

If you can live with a shot of starting fluid when you get home live with it.