Johnson 15 hp fuel supply questions

I have a new to me Johnson 15hp Model # 15R79E. I'm assuming it's a 1979 model. It has sat for about a year. Prior owner said it ran very well.......

I kept it in heated storage this winter and when I got my boat done in August bought a new fuel tank and fuel line, fresh gas and plugs. It started up, did not run real well but I took it to the landing. All went ok. It appeared to have a dirty carb. Did not transition well to high speed but I ran it and it appeared to get better. The next day hard start but it ran better as it warmed up.

Next day same thing although it actually died once at medium throttle. Now until it runs for quite a while I have to choke and manually squeeze the primer bulb for maybe 10 minutes and then it runs great for the rest of the day.
I don't know if this matters but I am using an Atwood 3 gallon tank with the new style hose connection at the tank end.

I have had on going issues with fuel supply. I think it's carb but I know it could be fuel pump as well.

How does one check the fuel pump? Do I just pull the start rope and see if pumps fuel? I took the fuel pump filter off and pumped the tank / hose primer and that supply's the fuel just fine so there does not appear to be restrictions.

Fuel pump? Needle and seat?

Any feed back would be appreciated

Be careful if you disconnect the fuel line from the carb so you don't squirt gas where you don't want it.Those fuel pumps can be rebuilt.I don't recall the part # maybe somebody else might chime in.Wouldn't hurt to pull carb apart to check for dirt or varnish.Cover all the bases.

The easiest way to check the fuel pump is to manually pump the primer bulb while the engine is running at the RPM the problem is occurring at. You will be overcoming the fuel pump while you are manually squeezing the primer bulb.
From the sounds of it you have a carb issue. Buy an OEM kit, which is the most complete kit on the market, and rebuild your carburetor.
Continuing to run the engine with a dirty carb may end up with powerhead damage due to a lean running condition.