[dirty hands]

Apart from the usual petrol evaporation problem the fuel system a telstar has -where once it gets hot the fuel turns into vapor and stops and wont start again while driving or stop starting ( fuel pump and carby both empty )
not much you can do about the problem either

The roadside breakdown service put a cold wet rag around the carby to get her going again (so many times )had to crank for ages

so carry water and a rag and if you can get a see through fuel filter so you can see if the fuel is pumping up

the fuel pump may stick internally as well causing the same problem

I assume you already checked the choke was working if not the butterfly might not be open eneough or closing on acceleration

A carby gasket may have a leak and is sucking in more air in than it should through the sections that come apart

Icame accros the gasket problem by accident the car would loose reves
I had to stop the car she started straight away then up the road she would die again
Pulled the carby apart and the top carby gasket had broken on one thread
try to retighten the carby screws and go for a run
I assume you already changed the fuel filter and all the stuff I did
I was going to put a longer fuel line and insulate it from the heat better in so it kept it away from the engine but didnt solve the problem on very hot days