Merry tiller 5hp quantum

I have an Atco merry tiller rotorvator which is a very well made piece of kit. It has a briggs and Stratton 5hp side valve engine from 1988. The throttle linkage came adrift and I can’t work out how the thing goes together. I’m usually good at this sort of thing but just can’t get my head around it. Can anyone help with a sketch or image of how it works before I chuck the towel in and fit a Chinese unit! TIA.