There is a fuel tank strainer, that can get blocked from algae, presumably from aged diesel....type in" fuel tank strainer" in the search part. Same with the fuel filters. That should give you a place to start? How long did it sit exactly? How hard was it to get started?

Welcome.

P.S...your parts would probably be less than 50 bucks or even cheaper, if you could just wash the existing in tank fuel strainer filter... clean and re-install...that strainer part is something like $33...and some people just clean the original and re-use if they are still good. There is a large o-ring for this part to seal, upon re-install, you may need? Not sure if it is included with the new tank strainer or needs to be purchased separate? There looks to be 2 fuel filters under the hood of that one. 10 bucks for the spin-on filter that looks like an oil filter and 3 bucks for the small clear plastic pre-filter.