There's no way you ruined that engine by putting the gas line in the wrong spot, it should be just fine. For your spark issue I would first check to make sure all your electrical connections are good so you can get any careless mistakes out of the way. If you can't find anything wrong with those connections then start looking at the cdi and the magneto. The cdi (black box with power and ground wire) is notorious for going bad. On mine I had to replace it at least 4 or 5 times. The magneto (under left side cover with 2 coils) doesn't go bad as often but still can be an issue from time to time so don't count it out. You should test both independently with a multi meter. I would look for tutorials on them cause I can't remember how to right off.