Interesting Joe, i've come across a few of these carbs and many with different jets but never one like that. This might be a job for an exploded parts view. www.partstree.com is handy for parts lists, especially tecumseh's.

Peter, at full load the hole in the throttle lever lines up with the notch in the top plate, (both circled green), in the below picture. The screw i've circled red is your idle speed adjustment. At idle adjust that screw clockwise to increase idle speed. As grumpy said, the screw that is also in the second green circle is your high speed adjustment. Adjust that one at full throttle to increase or decrease your full throttle speed. As always be careful not to have your full load speed more than about 3200rpm. It's a small torx bit but a really small screwdriver will do it if you dont have a torx set.
Let us know how you go when it's done.
[Linked Image]