So the rails are cracked at all four engine mounting points, and most of the cracks have propagated for some distance.

In the previous pictures both engines had proper B&S air cleaners, so I take it you removed them for these pictures.

Here is what your governor linkage should look like:
[Linked Image]

Here is what your choke linkage should look like:
[Linked Image]

So far I haven't seen anything wrong with what you have. Unless there had been interference from the previous tenant, that is what I would expect. I suggest you go through the normal check-out procedure for a new-to-you engine. The objective is to make the engine safe to run, then see whether it has spark, compression, and fuel. So begin by seeing whether the sump is full of clean oil. If it isn't, make it so. Then see if it has spark. To do that, remove the spark plug, attach the plug lead to it, hold it against the cylinder head, set the speed control in the full choke, full speed position, and pull the starter. As the engine spins, observe the spark plug gap to see if there is a steady stream of blue sparks. If there is, you have spark, so you can reinstall and reconnect the spark plug.

Next, pull the starter and see whether you can feel resistance to pulling it, once every two revolutions of the clutch. Don't expect it to stop your arm as if you were cranking a Lister diesel on full compression, just see if it is noticeable. If it is, chances are it is enough.

Then, on full choke, pull the starter say, three times and see if the engine fires. If it doesn't, reduce the speed control setting until the choke is open (the slide moves all the way in, flush against the carburetor) and pull the starter three times briskly. If it still doesn't fire, but it has spark and compression, we need to focus on fuel issues. With the speed control setting still in the choke-open position, remove the spark plug and put a small spoonful of petrol into the spark plug hole. Reinstall the spark plug immediately, reconnect the plug lead, and pull the starter briskly three times. If the engine does not fire, one of the three tests we've just done (spark, compression, fuel) was invalid and we need to repeat them to find out which. If the engine does fire but then stops after a couple of seconds we've established that the problem is in the fuel tank/carburetor/intake port system, and we can focus on that.