I have an Ariens Lawn tractor and my daughter put in dirty old gas into the tank and ran it for a bit. Then it stopped and I can't get it started anymore. I dumped the gas out and put in new gas and it won't start. Tries to start but does not. What do I need to try and get it going? Another terrible thought is that it wasn't gasoline. It did not have much of a smell, maybe because it was so old. When I looked in the tank before I dumped it the gas looked pretty brown, but that could have been because this was old and dirty.