I haven't personally seen a manual for those old Lauson/Tecumseh engines. They must exist, but might be rather scarce. Bruce is the person most likely to have access. I doubt there are any parts available except by taking them off another old HK25. Most of the governor parts look the same as those on the vertical crankshaft HK25, so you might try looking for an ancient rotary mower with a Tecumseh or Kirby-Lauson engine - they used to be very common in the 1960s.
