Husqvarna TE 250 - 310 2011 I.E. Workshop Manual page 202

ENGINE REASSEMBLY
Install the crankcase (8) and tighten the screws (9) following a cross pattern
(use an 8 mm wrench , 10 Nm, 1.0 Kgm, 7.25 ft/lb). Make sure pump gear and
drive gear engage correctly.
Check the O-ring (10) for damage and replace it if needed.
Refit the spring (11) of the oil filter (12).
Refit the oil filter into its housing and tighten the screws (13) using an 8 mm
wrench (5.5 Nm, 0.55 Kgm, 3.98 ft/lb).
WARNING: When assembling filter to cover, make sure to fit the filter
oil seal (A) first onto the cover (6).
H.52 Ed. 07-2010