You can't really generate enough pressure twisting against that pin.
If you can get a piece of flat stock or even angle iron between the flywheel bolts you can give a much bigger twist and even a little shock from light banging. Always go one direction and then the other.
Another much better way is to remove the starter and using the starters hole protected with a block of wood or plastic to protect the hole then you can get a small pry bar against the flywheel teeth and give a twist, again one direction then the other. If you get a little movement it will work loose. This will give you the most leverage by far!!!
Dave Neptune