Running problems 1.1 Formel E

I have some running problems on my 1983 Golf C Formel E. I hope somebody can help!

Symptoms:

When the choke is out the car is really racey there is a fine line between racey and cutting out when trying to get the choke in the right place.

When it is warm with unleaded fuel it nearly cuts out when the choke's in, with super it's still quite racey.

When the car is revved the revs take ages to drop.

It just doesn't run right!

It has done 126k but I have nothing to back this up.

Any help would be much appriciated.

Thanks

Leigh