Bruce, you are a legend. As usual, I have learned heaps about things I didnt need to understand.
On removing the muffler, it was as clean as a whistle, visually. No carbon as it had only run from new a max of 30 minutes.
However, on trying to blow compressed air out the exit hole (spark arrester removed) I couldnt. Nothuing visible, but on poking a screwdriver in there, hard, some dirt came out. A !@#$%^&* wasp had built its nest in there.
All now well, and I now know how the carby is made, what screw does what etc.
Many thanks to all who helped in solving this problem. I shall make a donation.
Cheers
Doug
