Most of that manual is a fairly minimal update from the 1984 classic manual, but the 1984 one did not cover Governed Idle, or emissions carburetors. I sometimes find the 270962 manual takes some fathoming unless you have the machine in front of you. In case it helps, most vertical crankshaft Governed Idle engines have their idle speed adjusted by bending the stationary tang at one end of the second (idle speed) governor spring. This is similar to the procedure for adjusting the maximum speed, with the tang at the end of the main governor spring. Note that your main governor spring is Item 209 on Page 6 of the IPL, while your governed idle spring is Item 211. There is a third spring (Item 629A) but it is only a speed control cable return spring, and has nothing to do with the governor: its role is to keep the Bowden cable inner wire from kinking when you reduce the speed.
I suggest that you post some pictures of the governor mechanism, showing the springs, the wire link Item 216, and their attachment points. That will be useful to other members, and will also make it much easier for us to discuss what is wrong.
