1) Remove the priming pump from the top of the fuel filter. It has a plastic retention cap that just screws on to keep it in place. It is just a large rubber flap with a button and a spring. I’ve found hockey puck-sized chunks of dirt here. Things seem to pile up on top of the filter housing below the priming pump. While you there you can easily blow the top out.
2) Remove the supply line coming from the fuel tank. See if you have good flow. These are just a rubber line. They are known to spoil on the inside. The gum comes off internally and the line clogs. There are several service bulletins on this. Buy a good quality line to replace it. Just a regular fuel line not something your need to go to JD for.
3) Take the line from the bottom of the fuel tank and see if it has good flow there. That reed is not that big. Trash can get into the tank and cover it. If you find things there, your aim is to remove the tank to clean it. I have a JD 5210 and have had to remove the tank twice in 3000 hours. It was used when I bought it and I think the previous owner did not pay attention to making sure the fuel was clean. Transporting fuel in five-gallon cans makes it easier for dirt to get into the tanks.