Hi Widget,
When I get something like that I just check for oil, check for spark, give it a squirt of starter fluid down the center of the filter and see if it will start, if nothing after a few pulls, try another plug and starter fluid. If I don't get a flutter or an indication it might run I just bin them. I had one that had a broken rocker, replaced that and it ran fine. All I have done with the valve adjustment is bring the piston to TDC compression stroke and make sure the rockers have play in them. That is near enough for these cheap motors. If I get one that looks reasonable and wants to run but it has a carby problem I don't bother with the carby trying to clean them (often they have been run on ethanol fuel so they are beyond repair) I just put a new $18/20 carby on them
