Hello
Burgo60 and
Mowerfreak.
Yes, this was an ungoverned carburettor.
The parts list make it clear all 2-stroke Imperials had an identical motor.
That parts list is available as part of the Record for this machine:-
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=72729The engine was special in that it had an engine compression spacer
and a heavily modified G3 carby.
Burgo, I hope you sort out the issues here.
Cheers
Jack