Hello, I have a Husqvarna RZ5426 with a Kohler 26 V-twin courage. Last November, I loaned it to my in-laws and it hasn't run since. I was told that they turned it off, went inside for a break, came back out and tried to start it. It turns over fine but won't fire or sputter. I load it up and bring it home, clean out the carb, everything seems fine. On further disassembly I discovered all the push rods bent, after replacing them later found the intake valve on #1 having a hard time moving, replaced it too. Everything all back together, still won't fire and now it's shooting gas out of the exhaust. What did I do wrong, and how did it happen in the first place? Any help appreciated. Unit is an SV735-3031, serial #4214401613 with 96.1 hours.