My basement ain't that big!!!
That is for sure a governor. Traditional synchronous generators must run at either 1800 or 3600, one reason some of the typical 5--15hp home ones are so noisy. Many Onan twins run at 1800
I made "big" points one time at the big parts store. I had been snooping, and had discovered a NOS belt drive governor down on one of the dusty shelves. One day a fabricator came in "could we get one?" I told him "I think we have one" and startled him and the boss when I dragged it out
Putting a gas engine in a basement is not a good idea without adequate ventilation. Around here we've had at least a couple of injuries I'm aware of because of boat engine bilge explosions, and this not a "big boat" area, not like the coast or the great lakes
That temporary clamped up exhaust pipe looks like CO waiting to happen
The bellhousing such that it is must be some sort of idustrial setup I know some of them have (forget what it's called) --standardized series of mate-up, "SAE" sizes