1710 fuel ussues

[double hunter]

I have a Ford 1710 that I picked up a while back and have been doing a little work on, I am having some kind of fuel issue, it is hard to start but runs good once it does, have to pull accelerator all the way down to crank, it will crank and quit likes its not getting fuel and then will eventually crank, I checked the fuel line connections and I don't think they are sucking air, tractor runs good at full throttle but will not run a slow speed, was running it today and it finally quit, would just hit, it doesn't matter if it has run a while or not, still hard to crank even when warm, the previous owner had an electric fuel pump between the filter and input to the injector pump so this has has been an issue, makes me wonder if the injector pump is going out, tractor seems to have good compression and does not have any blow by, any help appreciated