Hi L.A.B.
Thanks for your explanation of what the throttle screws are. I can keep the engine running by running the engine fast (plenty of throttle) but the minute I throttle back the engine dies. The original sponge filter fell to pieces when I took it out so maybe the filter acts as a choke? The parts page you sent me was issued by CMS in the Netherlands I will contact them and see if they have a filter
as I can't source one in Uk.
Thanks again,
Richard