Engine Problem

Hi guys, just wondering if anyone had the problem I'm currently having. I purchased the golf not too long ago with a slight engine problem. 
The car starts and runs until it reaches temperature but then cuts out, I don't think it's anything major but for the brief moment that it does start there's air bubbles in the fuel line. In addition to this the fuel filter was on the wrong way. If anyone has a slightest idea what the problem may be I'd appreciate it!  Thanks 

I could be a whole host of things but start with the basics things.
What carb is fitted to the car? If auto choke then it's probably a Pierburg  carb (original carb) or if manual choke is a Webber.

I could just need a tune up as it's seems to run ok on the choke and die when the choke is not needed?

What is the fuel filler neck like, any rusty holes at the top, you can look inside from the filler cap.

Try taking the pipe off going to the fuel filter and blow down the pipe (you should be able to do it with your mouth and hear bubbling in the fuel tank. This will clear any blockages in the fuel pipe.

How old is the ignition system, HT leads, spark plugs, dissy cap and rotor arm?

Air filter OK?

Few things to get you started.