I have a model 136212 b&s 5hp fun power go kart that was giving to me for my two sons.The only problem is I dont have a clue on how to get it running .
ive took the carb and gas tank cleaned and put back. It runs for about 30 sec. then dies. I have to put gas into the carb in order for it to start.What else can i do ?????

There is still some obstruction in the carburetor, fuel is not getting drawn up and fed to the engine. It may be a problem with the fuel pump diaphragm, the main pick up tube may be clogged or there may be a clog in the main jet, or a combination of these things.

Or the use of old fuel... or overuse of addictives..