Hard to start after sitting

[lowesguy]

So my truck runs really good! passed smog test better than my imports! trouble I've always had with this truck is after it sits 3 or four days,really have to pump it 10 times or so, crank it over 4 times maybe ,then fires right up, I changed the carb about 15 years ago,think the old one was bad,anyways I'm pretty sure the automatic choke is bad,doesn't seem to move the top plate closed,what else could it be? once the truck starts,runs great,did a complete tune up in Dec. Thanks John