carburettor base flange air leak problems 1.8 89 clipper

Hi
I have an 89 1.8 clipper and have just removed my pierburg 2e2 to give it a once over check and to try out my spare couple of 2e2's that I have in my shed, and now after trying them(they ran fine) I have put the original back on and it started and ran fine until about 5-10 minutes into my journey I put my foot down and the car spluttered then cut out and stopped in the middle of the road, within about 30 seconds it started again and just got me home but now I can only get about half a mile up the road before it cuts out again and the process starts again (30 sec, start, just get home)
Does anyone know how bad your car runs if the base flange is letting in air this is the only thing I can see might be wrong as when the car is running on tick over if I spray carb cleaner at the base the idle drops down a bit so I assume it has an air leak but would this air leak be enough to cause the cutting out.
I have checked my plugs and they are perfect, distributer/cap and leads all ok and have no reason really to doubt the coil
fuel filter is also new and i have cleaned the carbs internal filter
i also put one of the other carbs back on and it still runs, half mile, cut out, 30 sec start, just get home.
any help much appreciated as it was running fine before this and i only removed it to give a quick clean and a once over.
cheers kurt

wiggle the carb while its running, if the idle changes swap the flange. any air leak is bad so get it sorted

Hi john
I will try that see what happens, the carb spray certainly makes the idle drop when sprayed at the base.
I just can't believe that the base leaking could cause the cut out problem but I have ordered a new base anyway, so I can rule it out.
I assume its the original base so due for a change anyway

I'm having the same problem. Did you manage to find out what was wrong?