I have a Briggs & Stratton 13.5 HP L head engine that has suddenly seems to have an overheating problem. It stopped mowing one day when my wife was using it, and I found that the keeper had come off the intake valve. The intake valve stem looked a little dinged up, so I got a new valve stem and keeper. I must have done a poor job of lapping it in, because now I have, I assume, an overheating problem, and the intake valve seat pops out after 10 minutes of operation. I've read topics on peening to reseat the valve seat, but I'm wondering if it is too late for reseating and relapping, or if it is destined for a machine shop.:(

Take a small punch and make about 4 small dempels in the aluminum up close to the seat that should hold it in. Tap it in evenly