Post #15 Gr8, interesting how they've drawn that but photo of the part down the side part #5 looks normal to hold the Oring#7. Hard to imagine it working any other way.
If parts can't be found maybe do some thread trickery & fit a 'short' main jet direct in place of the 'jet setter' Oring holder.

Uhh, so now i read Marks post #16.
I learn every day!! & never seen that type.
Maybe i'll go look in my AT1 carb & might find that type.
I think in that parts drawing it looked hex shaped but i'm guessing it must be round to push through an Oring.

Two things seem to always happen. People call on the phone saying their main jet is too large. I ask’ does it have an o ring? They don’t understand yet.

The other question is’ which o ring is smaller?
The 248 prefix or the 214 prefix.
Theres a big/small difference.

asco