I started tearing into the 19 year old B&S vertical shaft motor from my Snapper RER today. It had been bucking and stalling really bad after warm up and no amount of carburetor repair or other maintenance would fix it. I figured since it must have hundreds of hours of it by now, it was time for a tear down anyway. One thing that was out of whack when I took the PCV-valve cover off, was that the intake valve spring was off center and kind of cockeyed. This engine has never been torn down before and ran great right up until this spring, so here are some questions: 1. How could this happen by itself? 2. Could it explain the bucking and stalling, like locking the valve open after warm up? I will finish the teardown tomorrow and if I find anything really interesting I will post pictures. I want to diagnose my problem to the point where I decide to buy a new engine or get a rebuild kit (about $60 from PSEP so definitely where I'm leaning).