Craftsman gas pressure model#580-752220 willnot stay running. Only after you push the primer 10-20 times it will start &run for 5-10sec..It will run if you pour gas in carburetor.If you quit with the gas it will quit to.Have put new primer bulb & new intake gasket. What could be wrong? the carburetor is like new inside. It is getting gas.

Check for a blockage in the main jet. It may be like new inside but a small amount of dirt or gunk will stop everything

Sounds like the idle jet in the carb is plugged up.

It only stays running from the primer load, then dies when that is used up, as the gas can not get from the float bowl through the idle jet.

Did you store it for a while with the gas still in it?

If so, what happens is the gas starts to go bad, and over time it can get almost like a varnish.

When this happens, it starts plugging up the small ports in the carb, starting with the smallest, which is the idle jet.

Before storing for any length of time, your best bet is to drain the gas and run the float bowl dry.
If not that, at least add some fuel stabilizer to the gas left in it, and run it for about 5 minutes with the stabilizer in the fuel.