[SimonIG10]

I bought an old mower off Ebay for the allotment. After much tinkering it runs great but I have now noticed a fuel leak at the base of the carb when it is running. Its on its second set of gaskets but there is still a leak. I think its coming from the rear of the carb and wondered if the o ring could be the problem. The plastic retainer tends to come off when the carb is removed. Is this likely to leak. Its not a massive leak but in a short while the area around the carb on the top of the tank becomes wet.
It doesn't appear to have any cracks in the carb body.
Any ideas?

[grendel]

also check the fuel pipes, they can degrade with time