i have a toro 824 snow blower and its pretty old. It hasn't been able to run for a couple of years now. I rebuilt the carb and it wasent getting a spark off the coil so i replaced that to. well now i go over to start it and it still wont start.. all i know is that im getting a spark and fule is getting to the piston. the only thing is that it wont start over ... what should i do ??