Re: Sears LT/10
Might be a stuck valve. Sometimes, if an engine sits for an extended time with a valve open, it gets "varnished/rusted/gummed....etc. " into place.
That probably has a valve cover behind the carb. I'd pull that and make sure the valves are moving. Or pull the head to do the same.
BTW, when shutting off my small 1 cylinder engines, I pull the recoil cord until I feel the compression stroke. This insures the valves are closed and the cylinder is "sealed" from the atmosphere.