Update, Sunday arfternoon.
Well, I popped the end off the carb and checked the diaphram - it all looked in place and solid. Peeling back the diaphram I couldnt see a letter 'c' under there anywhere, but I took the carb off the crankcase (un-'screwed' it from the bayonet fitting) and looked in that end I could see letters and numbers there. There is a gap in the housing and I lined the letter 'c' up with that. I assembled it all back up and started the mower on the first pull (nice). But! It still revs like hell at full throttle (like it did before - no governer) and now as I throttle back, it slows down as I pull the throttle and when I get to about the 'cold start' point it suddenly revs back up again, so it seems I have altered something, but not the way I intended. At least before it idled and was a bit more controllable.
I guess its time to shell out and let the pros have a go at it; I think it is getting beyond my meagre understanding.
Thanks for your help Bruce.
