Df 6 cold start issue

[Potter]

My df 6 is used about once a month and has at time been difficult to start. The usual symptom is that it will only idle roughly with the choke on and die as soon as any throttle is applied. It has taken me a good 3/4hr to actually get underway, with no apparent reason for it to have "fixed itself". The motor is only a few years old and in very good condition.

To me it is a fuelling problem but before I start pulling the carburettor jetting/fuel system apart I would like to know whether this is a common issue?

Thanks