A fellow I know has had very good luck over the years by pouring diesel fuel into the cylinders and going through the same routine of waiting and nudging the crankshaft. Marvel Mystery Oil works great also. If the engine turns you at least have a CHANCE of an engine that will run OK, by not trying at all, you have zero chance of a good running engine without a total rebuild. An engine that turns is also easier to rebuild than having to knock the pistons out with a sledge hammer.