After replacing the governor, did you do the static and dynamic governor adjustment? Also, assuming that you had to remove the cables to install the new governor, did you ensure that they are tight enough in the clamps? Lastly, did you reuse the springs, and if so, are they worn out maybe?
"Hold throttle wide open and turn the governor shaft the opposite way and tighten"
Not sure what this means but you loosen the governor arm clamp, hold throttle wide open, turn the governor shaft coming out the side of the engine clockwise and re-tighten the clamp.
I can send you a Service (Overhaul) Manual for this engine if you don't have one and want one. Address below, put in proper format and remind me what you want, engine model etc .
Walt Conner
wconner5 at frontier dot com
What was the reason for replacing the governor in the first place? I ask because I was on this road a year ago with my 44M777.