Guys,

Be careful. It is not only the membrane that is restrictive on the smaller clunks. If you cut one up you will find that the holes in the metal core of the clunk are also very small and that contributes to the restriction that is causing the problem.

I have not sectioned the larger one to have a look but it might be a good idea to sacrifice a pickup in the name of research rather than potentially sacrificing a jet.

The membranes also clog up very quickly over time due to microbial growth within the membrane. Some of them run ok for a while but will quickly become sufficiently obstructed to cause a problem even if they do not create one immediately.

Craig.