Hey Norm,
I have played around with it a bit more. I intend to try and mount it a bit further in, but it is pretty short of where it should be, easily a good 2-3cm. This also has an effect on the cam, where pushing it forward to run doesn't quite make the cam fully turn to full power. I am guessing all of the problems stem from that throttle cable.
For all intents and purposes, once used to its wackiness, you could now use it as a lawnmower. It starts fine, it cuts fine, it uh stops halfway between run and start...and you can can have either run or start as your preferred grass cutting setting on the throttle control!
I will have to keep my eye open for a new throttle cable. There are some online, but once again, the price of them is the price of another s-box old mower and change, so not an option.
