I usually lurk in the back ground and read the forums to learn new things. I am a retired auto mechanic with very little experience with small engines. I came across a self propelled Snapper Hi Vac mower with a 5 hp briggs motor. The guy said that he couldn't get it to start and he wanted $30. for it, I bought it for 20 thinking that it was going to be an old gas, dirty carb problem. When I got it home I tried starting but it was a no go. I checked for spark first , it was a good and had a new plug in it and the oil had just been changed out, while the plug was out I wanted to check compression then I remembered I loaned my gauge set out several months back and it had not been returned yet, I covered the plug hole with my thumb , there was compression but no idea how much. I removed the air cleaner and gave the carb a shot of cleaner , it didn't even try to start. I kept trying for a while but I figured there must be something else. I checked the fly wheel key, it was in place as it should be. I removed the side cover to see the valves and they were moving. I removed the cylinder head, the cylinder is in good shape , smooth and no scarring, both valves open about 1/4 inch. I have photos of the head and block, does anybody have an idea? I'm only out twenty bucks if I don't get it going so it's no big deal. Thanks for this and all the things that I have learned while lurking.