Qualcast Cultimate B66

I am trying to identify the engine on a Qualcast Cultimate B66 that I have recently bought, there is no information plate, pics attached, also need to know what the triangular shaped 3 step switch is used for on the carb?
Many Thanks
Alf.

Many Thanks....I have since learnt that machine may be a Merry Tiller Cadet revamped for Qualcast.
When I bought it the petrol tank was attached to the handle bars by plastic ties which I removed so that I can fold the unit up to get into my car, I am now trying to work out how to attach it to the engine.
Thanks again,
Alf