Apologies in advance for probably the dumbest questions to appear on this learned forum. Where do i find the power jet in the TA21A carburettor? looking at the bottom of the carb body with float bowl removed there is a central group of 3 orifices. One holds the main jet, needle jet holder/emulsion tube, one holds the slow/pilot jet. On my carbs the third holds a thick brass tube that extends almost as far down as the main jet, with no slot or hex shape to facilitate removal and it is resistant to gentle twisting with pliers. It is also not readily apparent in the parts diagram. The carb model number is on the float bowl only. Do i even have the right body?

Also, can the needle be replaced without removing the whole slide operating mechanism? The manual says not to remove it unless necessary and there are two security screws which require a special tool holding the back plate to the carb body so i think they are serious about not removing the back.

By way of context: trying to fit the jetting kit which requires plugging the power jets.

Thanks for all help.