Fuel leak

Hello All,
I have 1981 KZ650 model and I am working on it to be able to ride this summer. I had carburetor issue last winter. So instead of fixing myself, I got it serviced fully from a Kawasaki dealer.
Today Installed the Carb, Throttle Cabels, and also cleaned the petcock. After everything was assembled, & when I turned the Petcock to Prime position, Pulled the Choke to start the engine,there was a fuel leak from the carb. I am not able to get the engine started (push button start). This happens only when I set the position to Prime. I might need to adjust the idling screw, but I should at least be able to start the engine first and I am not. 
I am not sure if this an carb problem or something else. I would appreciate your help. Could this be Carb problem ? ( I hope not, because I paid $$$ to get fully serviced.) 
Am i making any mistake on my side as far as starting is concerned. This is my first time working on this motorcycle.

Regards
Narendra


 

Verify you have the fuel line attached to the carburetor fuel fitting and not to a vent fitting.
The float valves should keep the carburetors from overflowing when the petcock is in the prime position.
 

Sometimes a float will hang up, causing a leak.  Rapping on the side of the offending carbs float bowl with the handle of a large screwdriver often persuades the float to drop down, and seal again.