I did that once, the governor was not re-assembled correctly.
Look on page 82:

"3. Move governor lever toward carburetor as far as it will go (wide-open
throttle) and hold in position.
4. Insert a nail into hole on cross shaft and rotate shaft counterclockwise
as far as it will turn, then torque nut to 6.8 N·m (60 in. lb.)."