Timing gears

[Bob Culver]

I acquired a pile of used gears. These came in a wide  range of wear and meshing depths and short of trial assembling each it is tedious to assess. Apparently timing also varies markedly. Every time the gears are disturbed material is worn away to establish a new mesh. 
Unless the gears are otherwise very  noisy I would leave well alone. The mesh pattern seems to barely reach the chip.
If changing, beware tight gears lead to major failures.
It would be worth very close look to ensure that whatever action caused the chip has not caused cracking further in.
Perhaps smooth off the sharp edges.