[Ratters]

Make sure you are shimming using the shell alone and gears shimmed only. test fit and us a small push device to test for side to side lateral slop in the gears by pushing back and forth on the gear shafts individually.

for the final test screw it together and check for spin and any lateral movement.

next, check the sector gear engagement point on the piston, does it need it's aoe corrected?

Does this aeg use a ball bearing spring guide or piston head, this will also smooth things out.

if free movement of the gears, sector engagement is good then reassemble, check the tappet plate is moving freely, plug in the battery, test once, adjust motor height if needed, carefully, see if it smooths things out and cycles better.