Throttle Trigger Lockout (Assembly) - Husqvarna 50 Workshop Manual

Drive out the pin for the throttle trigger. Raise the throttle
trigger up into the handle and unhook the spring.
Assembly
Insert the spring down through the recess in the handle.
Hook the spring onto throttle trigger.
Align the pin hole in the trigger with the corresponding
hole in the handle and install the pin.
Insert the lockout lever making sure the end of the spring
fits within the lever.