imgur.com/a/c4aRR4M

I noticed when I put the bowl on to the carb with the new o-ring that the bowl sits down on the gasket where as when attaching the bowl to the carb with my old o-ring the bowl would have to be pulled down to the gasket with the screws.

I have no thick brass washer that goes on the needle jet nor do I see one in the parts diagram.

OK could be my bad!!. Forgotten what bike you have but just trying to get some sense out of partzilla picking a 1972 AT2 it shows a screw in needle jet complete. So I'm standing in the bad boy corner. How does the bike run now, is it OK on throttle because if the Oring isn't sealing it'll go super rich & not want to rev out. My thoughts are your old Oring was something someone fitted that's too big & was getting hung up. Hence needing to pull it up with the screws.

Thanks for pic.  Looks right to me, I've never had to use the screws to push the float bowl over the oring so I agree that was probably due to the wrong one being used.

so with that new oring it was way too rich every where except idle. it would idle fine but was very blubbery, would barely move itself and i could get up to almost 25 mph. I had a different carb that had the mj screwed into the needle jet (so no oring) so I swapped out the needle jet and bowl and the bike runs very good except at wot which it is still blubbery. I went from a 160 down to a 150 and will try a 140 tomorrow.
With the 160 in it would be cutting out at wot and I could back off just a little and it would start to pick up speed and I could then slowly roll it open and it would not be very blubbery.

I hope this makes some sense as I am not understanding what is going on.

I'll get shot at dawn for a week for suggesting this but i'd try a cheapy new carb just to see what happens.
Have one similar on my bike but had to reduce the main jet size which meant changing threads a bit.
www.aliexpress.com/item/1005012392026577...%7C_p_origin_prod%3A
Mine expanded into a 175 from a piston port 125 but principle is the same as in trying things.
Here's my video from a few years ago for a laugh--or cry, poor old girl.
Bit rich & safe on full song but that doesn't show up in reality when in use & pulling hard.
Not in HD so doesn't expand up very clear.