I just went through my 7 year old Walbro catolog and here is the list of Wt carbs with accelorator pumps, and hi and low needles and no primers.
12.7 mm
Wt 513-1 There are a few smaller ones listed also. motorhd
Wt 537-1
13.49mm
Wt 171-1
Wt 172-1
Wt 228-1
Wt 451-1
Wt 480-1
Wt 540-1
Wt 542-1
Wt 555-1