Well I said I would reply when I got my tractor back so here I am. They said they found particles in the bowl and water in the gas when they first contacted me. They replaced the fuel filter and two gaskets on the carburetor and a gasket on the air filter. The receipt claims they replaced the head gaskets but it is not listed in the parts so I'm not sure what they did there. I do know it was $20.45 in parts $9 misc charge and a total of $205.91 including tax final. So far it in the couple of test runs it has not backfired. They didn't bother to change the oil or oil filter even though a gas smell in the oil was one of the reasons listed as to why I was bringing it in. I plan to run it a few times before I sell it to make sure it is right, I sure hope it is because I can't do to someone else what the guy who sold it to me did.