I’m working on a Kubota M105xdtc tractor. After I run the tractor under load for 30 minutes or so it will bog down like it is running out of fuel. I’ve replaced fuel filter, cleaned water separator, and even replaced the small mechanical fuel pump on the side of injection pump. I also opened fuel cap just to rule out a venting issue. If I kill it and let it sit a minute it will run for 10 or 15 minutes then bog down again. Any ideas?