Here is the assembly instruction for the governor inside the crankcase. Let's see if yours is correctly assembled, and where that washer should be. Also, while I think it isn't very likely the governor shaft could stick, I think the slider and centrifugal weights could do so fairly easily.
[Linked Image]

You should also go through the process for adjusting the rotational position of the governor lever on its shaft. To do this you loosen the clamp bolt, pull the top of the lever fully to the right (so the throttle is wide open), hold it there, and rotate the governor shaft clockwise as far as it will go. Hold everything in that position, and tighten the clamp bolt. Don't overtighten it.