I posted a couple weeks ago with questions on this engine in an old Cub Cadet. I went through BS guide on trouble shooting and determined rh spark was intermittant so changed that coil and while apart I went through carburator. After this it still wouldn't start, had oil filler cap off and noticed intake rocker wasn't moving. Found that push rods on both intake valves were not on the rocker arms. Pulled them out and straightened slightly and reinstalled and adjusted valves. Runs like a pro now. Have been told this can happen from a backfire. Previous owner said he was running it and shut it down, wouldn't start up again. That old engine and Cub Cadet are really built to last compared to other riders I have worked on.