Cat 426 Backhoe shut off after 2 hours of run time

Hi ,, I'm new to this site ,but have been reading some of the post here and have found very helpful information.
I have a late 80s Cat 426 back hoe with a Perkins 4.236 . I have replaced the fuel filters and installed a new mechanical fuel pump. I have cleaned the fuel injectors and fuel lines. Bleed the air out and am able to start the machine. It runs good and will stay running for exactly 2 hours, ( I have time it the last six time I started it up) then it shuts off like it's out of fuel,...

Cat 426 Backhoe shut off after 2 hours of run time

Cat 426 Backhoe shut off after 2 hours of run time