30-01-2020, 09:11 PM
(This post was last modified: 30-01-2020, 09:12 PM by Steve Jones.)
Before any changes to the carburettor, I'd make sure you don't have an air leak at the manifold/carburettor joints. The problem you describe is typical. Whilst I have no knowledge of Big Sevens and no spares I do, probably, have a carburettor you could borrow. I'm only about 10 miles from you so worth a try once you're sure you haven't got an air leak.
Steve
Steve