Thanks for asking. At that time when I had posted, I had two issues, one was a desperate need to get spare spark plugs (broke mine) and the other was that my engine never held idle below 2700rpm. I had assumed for a while initially that the idling issue was due to my reworking the muffler to save weight (basically halved the chamber length and proportionately increased the opening). So I didn't bother to get back to BME on it at first, until I replaced to a spare Original muffler to find the same idling issue. I run a 14 x 6 APC wood prop. I looked at the carb last week and noticed that may be the coiled spring that tensions the butterfly plate may not be doing it's due. I am going to hook it in some way, only there doesn't seem from any pictures that I can get hold of, any obvious points to coil and latch this spring. How is it on your engine?

Regarding the Spark plugs, thanks to folks like you at RCU, manage to source it from CH ignitions.
reg, gyri