The base looks good for it's age Speedy as both of my Pope rotary valve mowers will need a small amount of welding done
on the bases.

I'd like to get my spare motor going but needs a fair amount of parts so probably cheaper to buy another mower

Once the carby arrives you will just need to adapt a recoil starter to work , If you
want the starter a similar size to the original then I would use a Briggs and stratton starter ,just drill the rivets out
of the Briggs starter and rivet it to the Pope cowl or make an adaptor plate ,this Pope is getting there.

I used a Sprint 3.75 starter on a Suzuki 2 stroke and it worked fine.

Cheers
Max.