I have a friend that has a Cat Dozer (see photo) and he can"t get to run. He says that it runs well then sputters and quits. He as ordered new filters, but the ones in there aren"t that old. He initially used it for about an hour digging and it ran well. He as removed the filers, drained the container the filters are in, opened the main fuel line and let it run slowly for while to hopefully drain any water out of the tank, filled the filter container half full of diesel, replaced the filters, bled the lines, restarted it and ran well for a short time and then died again. Any thoughts/recommendations?