1950 DC Case Governor linkage

I'm interested in the function of these two stops on the governor linkage. My manual says little about these settings.

I put a rebuilt carburetor (same model) on the DC and would like to reduce the idle on the tractor a little. So far my attempts to adjust the idle at the carb according to the manual have yielded no results. I'm assuming putting the new carb on has changed the throttle linkage settings somewhat and that is where I need to make my adjustments.
Where do I begin?

Thanks

The carb has three adjustments. (1) Power fuel mixture on the bottom. (2) Idle fuel mixture at a 45 degree angle in front above the bowl. (3)The idle SPEED adjustment screw and holder is on the outer end of the butterfly shaft.

It could be the screw holder is bottomed out at too high speed and the screw is not effective. If this it the case, keep turning the screw to increase the idle speed. If you can keep turning and increase the speed with the idle speed screw but not decrease the idle speed to your liking, the screw holder is bottoming out too soon and the end of the screw is not touching.

The two clamps shown in the picture are NOT for adjusting IDLE speed. The front clamp can be used to limit the high speed of the engine. The rear clamp, properly adjusted, generally keeps the tension spring from getting into a bind tending to break the hooks.

The throttle lever on my 49 DC was different than the throttle lever on my 52. The 49 lever needs the front clamp to limit the max engine speed otherwise the throttle lever can be "forced" all the way horizontal by "throttle jockeys". A little bending of the linkage at the lever made this easy to do. As a kid, I learned speed-up tricks so that made my a throttle jockey---but never when dad was around. The throttle lever on the 52 prevented this.

Thanks guys for your suggestions.

I wondered about that governor spring so that's the first thing to change.

Will play with those settings. I'm hoping to increase the engine speed to somewhere around 1500 Rpm so I can be a "throttle jockey" also.

But nothing like my little brother Chuck!