The timing is supposed to advance by 14 degrees when running. Subsequently - if the advance isn't working it will be impossible to manually adjust timing correctly by moving the pump. You can get the timing correct at engine idle speed, or a high RPM - but not both. Generally speaking - if the advance is not working as it should and timing is retarded at higher RPMs - the engine will skip when you try to rev it under no load. Might smooth out when worked.
That's why I mentioned the little round plastic timing window. It has circular degree lines. It makes a 10 minute job out of checking the full timing curve from 0 to 14 degrees just by screwing it on, running, and looking.
As others have mentioned - the pump itself has a timing pin hole, just like the engine does. All that does is verify the pump is static timed when the engine is cranking and has nothing to do with ensuring proper timing when the engine is actually running. If the pump has a non-working advance and you set it properly with the timing pins - it will be running 14 degrees retarded when running at high RPM.