No offense, was referring to the "repair shop........" comment, post #7.
If working on saw/machine you don't have a manual/IPL for and/or never worked on, take pictures or draw a diagram before taking apart. Then keep parts organized as they come off........I know you started with a basket case.
1) Check that the torsion spring, that goes behind the actuating lever that the handlebar bolts up is installed properly. The short leg must fit into the crankcase and the long leg goes into the lever (see shop manual picture). If the springs legs are not seated that could be the problem.
2) Measure the thickness of the handlebar actuating lever combined with the sealing washer and bell crank at the pivot where it connects. Compare that with the length of the pivot pin from crankcase to it's clip groove. Should be less than pivot pin groove to crankcase.