i just put a new choke cable on along with brass end and a new needle in the carb. my mechanic said he adjusted the valves.at first, but needless to say, being a 360 it is cold natured and not if but when it goes dead shortley after it starts. then it is very slow to starts and backfires and hisses and finally starts...what else to do is the question?? are the valves not set right or what??

 

Could be, especially if the intake valve is too tight.
Are you sure the choke got hooked up right? Once the motor is warmed up...if you pull on the choke...what happens?
The poping and backfire on a cold motor is a sign of being too lean. Either the choke isnt working or the mixture screw is too lean, or the pilot jet is too small. If the choke is hooked up right and working, id try 1/4 turn richer on the mixture screw, and see how it goes. It should get better,.