I just had the Snapper with the Tecumseh super 6 in the shop because it would not run. The dealer said they fixed the carb. It worked for a week and then quit. I did not have time to take it back. It has been 2 months and I really want to get this thing going. It will run for about 2 seconds and then quit. Everything seems to check out. Would a bad head gasket cause this? If not, what?