Kohler CV15S governor replacement

I'm working on a riding mower for a neighbor and it would seem that the governor is inop. The engine free revs to the point of floating valves at about 1/2 throttle. throttle cable travel and choke operation check out, static governor adjustment is good, but there is no tension against the gov spring

craftsman 42" riding mower Kohler CV15S 15.5 HP single

My big question is:

can the governor gear be replaced by splitting the crankcase or is complete disassembly required?

any step...

Kohler CV15S governor replacement