Hi Maverick, and welcome to Outdoorking.
The symptom you have described - cyclic variation in the speed of a governed engine - sounds like a common problem usually called "hunting". In the great majority of cases, the cause of hunting is lean mixture. Your Victa may have accumulated some crud in its fuel tank and it may be obstructing the filter they usually have in the tank, at the fuel outlet fitting. You will need to clean that filter if it has not been cleaned recently, and verify that fuel flows full-stream from the fuel pipe at the carburetor end, when it is disconnected. If it is not the filter we will have to talk about the carburetor, and whether it has crud accumulated in its float bowl's needle and seat (i.e. some of the sediment has found its way past the filter), but I suggest you begin with the filter and only attack the carburetor if that is not the problem.
In an unrelated matter, the clearance between the two laminated steel poles of your ignition coil, and the flywheel, should be 0.010-0.012", which is the thickness of an ordinary visiting card. The amount of clearance, and it being equal on the two sides, is fairly important.
