Clutch Start Switch

Fully depress the clutch pedal and hold it.
Install so that gap (A) of the clutch pedal plate and clutch start switch is 2.9 mm (0.11 in), and tighten the lock nut.
Tightening torque:

8 N.m (0.8 kgf-m, 5.9 ft-lb)

Fig 1: Identifying Gap Between Clutch Pedal Plate And Clutch Start Switch
Courtesy of SUBARU OF AMERICA, INC.
Connect the connector to the clutch start switch.
Make sure that engine does not start with clutch pedal not depressed.
Make sure that engine starts with clutch pedal fully depressed.