When re-building my Strombergs I found one with and one without the small "plastic washer" described on the back of the instruction sheet in the adjustments section. It fits onto(no. 8 on diagram) the metering needle. There is a groove in the needle where it meets the bottom flat surface of the "air valve assembly" that it rests in. I found no plastic washer included in the kit. Is it O.K. to run without this washer? The one that was left on the second carb. fell apart when I tried to look at it.
They are delrin washers, I was told when rebuilding mine they are not required after the needle asm is installed into the air valve. The washer provides for retaining of the needle asm during shipment.