Husqvarna 50 Workshop Manual page 30

After removing the tool, make sure the drive gear is
flush against the shoulder on crankshaft.
install the oil suction tube and filter in the oil tank.
Slip the pump piston into the pump housing. Fill
pump cylinder with grease and slide the cylinder
the piston.
Fit the cylinder into pump housing with the notch in the
cylinder towards the back side of the housing.
the
onto