Starting up

Just bought a mk1 golf 1981 a week ago, some times it will start first time and an hour later it will take ages for it to start up…. im new to cars so does anyone know what might be the problem?  

Thankyou

Jamie

be good to know what engine is fitted and what is an age, eg four or five goes.

certainly with myn, its a 1.8 with the peirberg carb,  can take a little persuation to start if stood for 10 mins or so.
But an hour should start up fine.