took the white plate off - unscrewed the screw (jet?), and when removing it, it had tiny bits of disintergrated black plastic in the thread.
Cleaned everything and reassembled (but haven't got the new O Ring yet).
It now only seems to leak when pumping the primer - however did get it started & briefly used.
Still to get the new parts, but not sure about the screw/jet - replace everything?.

Last edited by flatout; 14/11/13 11:58 PM.