I've never done the job on a Victa 2 stroke so you will need confirmation from one of the guys with the right experience. I am under the impression that the end of the crankshaft where the blade boss attaches is tapered, and the blade boss is retained by the taper. If that is correct (and you should be able to see the taper if it is held that way) it is rather similar to removing a car front suspension ball-joint. You hold a large steel block against one side of the blade boss, and strike the opposite point on the blade boss really hard with the biggest hammer you can handle with one hand. You need both block and hammer to be square against the side of the blade boss, and exactly opposite each other. One or a very few good whacks will make the boss pop off the taper.
