governor not working?

I have a briggs and stratton 407777 engine. Engine was running fine but losing oil. I removed the engine from the lawn tractor to replace the crankcase gasket.
when putting it back together i somehow damage the internal governor shaft and the small gear off the main crankshaft. I purchased new parts and put it back together. engine runs fine but the governor is not working. i purchased a new governor bracket and springs but still the governor does not stop the engine from running out of control. ANY IDEA WOULD BE APPRECIATED

BOB
April 2010