Just about all the older Deere diesels run near zero degrees with the engine idling and 16 degrees BTDC when revved up - just like a gas engine. The marks on the pump tell you when the static timing is correct. If you put a plastic timing window on the pump you can check the advance at higher RPMs.
Which pump do you have? A "C" that is round with a long tube sticking out the back where the throttle hooks up? Or a "D" with the throttle lever attached to the side of the pump housing?
Also, you say you replaced the pump. With what?