Wedge.
I removed my governor and modified my throttle linkage on my 18HP, and installed a high rev kit, I can now go to 5500 RPM with no issue, I normally only go to 4400 to 4600 as I dont have a good billet flywheel yet.. I can go to 31 MPH and the extra RPM's are great when going up hills and over trees.
the attached was given to me from a member of the "other place" whom I have seen on here once n a while.