Hi Bob
I will mesure the motor for you, (it is big and heavy). On top of the carburator yes it is a governer, it is use to control the water pressure ( When 2 lines or more are used )and also to protect the pump against water hammer. On top of water pump it is a cooler, in case the motor get to hot during long pumping operation( to my knowledge it never been used )I will be glad to answer you question if i can.
