1937 Ruby spark plug colour ?

[Joe eck]

Hi Ian.
I think that you may be correct about them being restricting devices as listed but not shown on the exploded diagram.
I will remove the remaining one and see how it goes.

It's interesting to note that although they are described as restricting tubes, the size of the "tube" is far  greater than the hole in the jet and therefore I am not sure how the actual restriction takes place ?

Thanks for the info, much appreciated.
Regards
Joe.