MTU Detroit Diesel 183 Series Technical Publication page 321

Task Description
20080/1 E 99-06
Bar engine slowly in direction of rotation and observe
fuel flow in sight glass until spray pattern shows correct
atomisation. The exact pump timing is achieved at the
transition.
A = Good atomisation
B = Poor atomisation "just before start of delivery"
C = Faulty atomisation (droplets)
Note
For engines with split-element injection pump:
Bar engine slowly in direction of rotation and observe
fuel flow in sight glass until atomisation is correct and
then dribble recommences (pre-injection).
Bar engine further until dribble recommences. At this
transition, the exact pump timing (main injection) is
achieved.
Group 07
Subgroup 8234
Page 5