I had a 14 hp kaw. FC420V and pulled it off and put on a 17hp FH500V twin. Every thing went great, Except I can't get it to shut off. It is supposed to shut down when you pull the throttel sp All the way down, and choke is all the way up. There is a Black wire on the side off the engine I don't know what it goes to. I guessing it has something to do with kill the motor. I tried to touch it to the block, but no effect . The motor is a pull start. The only way I can get it to shut off is to turn the fuel off, and let it run out. It takes 5 min though . I am going to have to drive down the road with my mower running on the trailer. lol do I need a kill switch, and if so what kind. Will a simple toggle switch work. Oh yea the new twin seems to be much smoother and quiter. Haven't used it yet so don't know about how much more power it has.