Hello. My question is about to propeller low rpm adjustment (1600-1640). The adjustment point is on the the lower of propeller levers where are the two nuts aft and fwd of the feather springs?

I suggest you post this in the Beech Turbine section to get a better response.

The adjustment is made using the nuts located aft and forward of the feather springs on the prop lever. You’ll need to fine-tune them for the desired low RPM setting. Hopefully that helps!