Fuel vaporisation

[demolitiondan]

The arrival of the hot weather is great but I'm having hot start problems. The engine spins away on the starter but won't catch if I'm trying to start the engine when it's warm. Leaving the car to cool down for an hour sorts the problem. I recently had an MOT done and the mixture is quite lean at idle (65ppm HC with 0.08% CO).

The car is 1980 3.3 Turbo, does anyone have any idea what the cause is and what if anything is a sensible remedy?

Cheers