find out the model number, year, ect. Napa might have a rebuild kit, and sometimes the rebuild kits come with directions about setting the floats, jets, ect.
Webbers are different, might consider calling the parts stores and book stores to see if any of them have Haynes manuals or Webber books. Carbs last forever unless they've gotten corroded. Even the jets can be re used/cleaned/reset. Its the lil gaskets for the bowls and horns that fall apart because of time.
Sometimes carbs like a good cleaning.
"Give 'er some, she'll come out of it!"
Anyways. I aint that good at carbs. I've fixed a couple snowmobile Mikunis, Briggs singles, one FIesta mess, and rebuilt one Rochester 2 barrel. A manual or book is the key because I'll just f-it up worse without one.
I had 2 Webbers on the Porsche 914, what a crazy deal that was. It took me 3 weeks just to get one connecting link. I could have build one myself in half the time, but hey, it just sounds so cool to say "dual Webbers"