On any well-used single cylinder 4-stroke engine, if the crankshaft won't turn rather easily by hand, you are in considerable trouble. The only times I've seen them refuse to turn after storage one of two things happened: either they wouldn't turn before storage either (i.e. they were seized up when they were stored) or water got into them during storage. The latter could only happen if they were more or less under water, or they were incomplete engines (missing air cleaner or manifold, or breather pipe, or some other part that let water get inside the engine). Mostly, if they had oil in the bearings when they were stored even rather a lot of water in the engine sump will not cause them to refuse to rotate - but just a few drops of water in the cylinder will do the job.
One point additional to my previous post: do not touch the crankshaft or any other moving part of any engine without making sure it can't start. For a B&S engine, that means disconnecting the spark plug lead at the plug end, and making sure it can't fall back onto the plug when you're not looking. You really don't want to think about what can happen otherwise. Like snakes, the only safe one is a dead one.
I'll leave your second question to somebody from the Brisbane area, such as Deejay.
