hello grumpy,
Thanks for your reply. I already have a downloaded copy of the manual to which you refer. If you have a copy- consider this-on p.15 of the manual at top image, showing the test air tube location - placing an air tube over the opening in my carby at this check valve location will not allow air to pass. I think that my check valve is of the long tube nozzle type described at the last sentence of para 3 on p.16. I have attempted to press it out from the venturi side as per manual with a flat bladed screwdriver, but all that is happening is that the soft brass nozzle is becoming misshapen - it's certainly not moving. Its shape will not allow it to be pressed out into the venturi area. I might have to drill it out and get another.
Unfortunately, I have seen neither hide nor hair of replacement main jet blocks/check valves on the internet. Do you know where I might find jet blocks?
There was grit on the internal filter screens and all three progressive idle jets were either partially or totally blocked.
Thanks, as usual
mustang
