I have a cat 247b that doesnt run very well when i get below a half a tank of fuel. I first thought it was water in the tank, so i drained all the fuel and changed the filter...no change. So then i filled the tank all the way up and it runs good. Wondering if the lift pump is going out, or is out.
I was working on a Cat 216 (which I think has the same engine), that was having fuel problems. I replaced the lift pump and it runs perfect. Cat tech told me these are known for going out so that would be my first guess. They're like $75.