The max RPM adjustment itself was fairly easy (just threading a little set screw in or out and tightening a nut). However taking off a bunch of parts to get access to the governor and get enough room to get pliers around the nut was not so easy, at least not on the i1050.
The governor is located at the front of the engine just behind the muffler. So I had to remove the hood, front bumper, muffler shield, muffler itself, and a few mounting brackets, before I had clear access to the governor controls and linkage.
Tools required were socket set and needle-nose pliers. Not necessary but handy was a cordless impact driver with a 12" flexible extension rod with socket driver on the end for removing brackets where the bolts were tucked away in impossible tight spots. Barring the flexible socket extension, you can use small crescent wrenches instead, but with very short strokes, so plan on being there a while.
If you haven't already, download the Service Manual for your engine from the
Kohler website manuals download page. For the i1046 this should be the 20 HP Kohler Courage OHV, 2 cylinder, which is Kohler engine model SV710. Put that model in the entry field and it will provide links to PDFs of both the service and the owners manuals for the engine. Here's a
direct link to the engine service manual at the time of this writing. If that direct link doesn't work, go the model number route above.
Then go to page 5.18 in the engine service manual. Myself I jumped right to the "High Speed (RPM) Adjustment" section since that was my issue, but you might want to do all the steps to get the full dynamic range of RPM. I basically adjusted the "High Speed Adjusting Screw" shown in figure 5.35.
Obviously it helps to have a tachometer handy during the adjustments. I just used the one I had already installed in the tractor earlier.
Again, MTD recommends running at a max RPM of 3600, not just for optimum cutting but also to make sure sufficient air cooling is provided to the hydros. However my local Cub dealer routinely sets all their tractors they service to 3200. So I guess opinions vary. I noticed 3200 definitely sucks less gas than 3600...