Dick Hanson. I too kill the engine after letting it idle. The reason is I want the enternal parts to cool down....then I rev to full rpm and throw choke to kill it. My reasoning is a cooler engine will not evaporate the incomimg charge. I do not want to loose any soaking effects wich soften carbon. The next day or when-ever you start up hopfully all or most uwanted carbon will blow out. Its great for the seals too. Never had a seal go bad! Regards Capt,n