Does it have compression? If so, how much?
Usually, people throw away engines for a reason. It usually isn't a good reason by our standards, but it is nevertheless a reason. Until you have found it and fixed it, you are on borrowed time even if you get it to run. We need to get the model, type and code - I can't help you much without them - but I suggest you focus on two main possibilities.
1. The engine may have valve problems, hence little or no compression - that may be why it was scrapped.
2. The breather pipe will have filled with oil when it was tipped over. The amount of oil still in in the pipe may be enough to foul the spark plug.
