With engine not running move govenor arm (have throttle set at full speed) you should see movement on carburetor throttle shaft, if no movement most likely wrong spring or spring not hooked up right, if you see movement start engine and with hand throttle in fast position you should be able to slow down engine moving governor arm, you also should notice it much harder to move if governor is working while running, if you can slow engine down you have a failure of govenor inside engine which will mean taking engine apart.