Small Engines (Lawn Mowers, etc.): Questions on Kawasaki engine, john deere 160, kawasaki engine

Question
I just bought a 170 JD lawnmower.The Kawasaki engine has FC420V on it.What HP is this engine?What is the switch with wire going to it on the bottom of the carb. bowl?The engine runs but it is not right.You have to choke it to start it every time even when it is hot.It tries to go dead at full throttle and you have to choke it to keep it running it does not have any power and almost goes dead when you enguage the blades.The brakes are not working and i tried to remove the caliper to free up the 2 pin plungers and broke off one of the bolts in the rearend and the other one is tight and i will probally break it too.Any ideas on how to get the steel bolt out of the alumiumn rearend?

Answer
Welcome to the world of John Deere repair.
The thing on the bottom of the bowl is the fuel shutoff solenoid.  The mower is designed to start only on choke, even when warm (it's an EPA thing).

I break the bolts everytime I do brakes. It sucks.  You need to drill out the broken bolt using the caliper as a jig. You WILL drill off center no matter what you do.  What I do is drill about a 5/16 hole and install a "helicoil" kit. It will repair the threads.  After you get this done go ahead and break the other bolt and repeat for the other hole.

The other option is Ebay.  Complete transaxles are readily available.
http://cgi.ebay.com/JOHN-DEERE-160-170-180-5-SPEED-GEAR-TRANSMISSION_W0QQitemZ29...