Hi, while doing a check of my fuel pipes etc before going away in the van, I found that the seal on the carburettor needs replacing as it's leaking (good job I did the checks!!!) what's the seal actually called? It's the seal between the top of the carburettor and the plastic air in take that sits on top. For some reason I can't upload a picture

Been searching for a replacement but not knowing what it is called is making it hard to find.
Thanks