Do not know just where to get parts for your F1-B, but maybe some of these articles in Model A News (MAN), The Restorer (TR) or Model A Times (MAT) will help you out.
ERA CARBURETORS (NON-MODEL A)
« The Marvel Rayfield R.I.F Carburetor » : MAN/64/2/30-32 (2017)
“TIP…Parts to Revise Valve in a Tillotson”: TR/19/1/13 (1974)
“That Funny, Square Bowled, No-name Carburetor (The Allstate Deluxe): TR/34/3/32 (1989)
“Tillotson Carburetors”: TR/40/2/12-15 (1995)
“TIP…Curing the Tillotson Drip”: TR/40/2/23 (1995)
“Model A Era Carburetors (Non-Model A)”: TR/40/3/12-15 (1995)
“Simmons Carburetors for the Model A”: TR/40/4/15-17 (1995)
“Zenith Replica Carburetors”: TR/40/5/10-13 (1996)
“(More of) Model A Era Carburetors”: TR/40/6/10-14 (1996)
“TIP…Easy Carburetor Bolt Access”: TR/56/2/49 (2011)
“NEW Tillotson Carburetors”: MAT/4/1/26-27 (2008)
“Modern Weber Carburetor”: MAT/5/4/12-14 (2009)
“Tillotson Carburator Repair Booklet”: MAT/6/4/7-8 (2010)
“Mark Auto’s Tillotson Carburetor”: MAT/7/1/8-9 (2011)
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