Norm, you only assume I over-revved it. You were not here. Although it was running a bit fast I would not say it was running overly-fast. The problem was that even though I immediately pulled the throttle position from choke back to near stop, it kept running at the same speed. Was this a problem with the carby or governor? Perhaps. All I know is it all happened in about 5 seconds, in the blink of an eye. And I have since learned that I had everything set correctly. I still maintain it was a combination of worn out parts, metal fatigue, age, and, as you suggest, too many weak little components. If you could see that camshaft and how brittle the metal is, you would soon see what I mean. It is like chalk. In fact exactly like chalk. And this part has to push the valves up and down. No wonder it failed.
Over-revving a restored engine is often difficult to avoid. In fact three out of five of the Southern Cross engines I restored did over-rev on their first start. This seems to have been due to worn governors. In their case I had to physically tighten the springs on to the governor arm so that I could push the governor lever as far back as possible with the throttle control in order to get them to idle. Once I can get them to idle it is then a fairly easy job to sort out the correct speeds with the control. Not every old engine is the same, even if they are the same make and model. They all start differently and sound different when running.
A lot of it is just luck of the draw when it comes to restoration. Old parts are bound to fail, sooner if not later. That is a fact of life that I am prepared to accept. It is possibly far better if they fail straight away than later on, like after I've sold the mower to someone else for example. But I guess then I can blame the new owner for over-revving it? lol!
