The Tillotson Nozzle Check Valve has the primary function of protecting the inside of the carburetor in case of a backfire.
The check ball seals off the inside of the carburetor preventing damage. While the nozzle length and shape can influence the signal and the carburetor's tune, the check ball itself is not a tuning mechanism.
If you are experiencing a flooding condition where the high side is leaking fuel at idle, the check ball is not the cause of this problem. Most often, this is due to a leaking seat and or needle valve not sealing.
Most Tillotson Nozzles are press-in, but some carburetors use a threaded nozzle. Be sure of which one comes in your carburetor before pressing them out. When replacing the nozzle, make sure the adjustment screw is not in the body as it may damage the needle. When the nozzle is put back in, make sure the side hole lines up with the pick-off hole, the fuel circuit's hole where the adjustment screw goes, or you may experience tuning and performance issues.
Always check your carburetor listing before ordering, and if you don't have a listing, measure the length and diameter to match your nozzle.
Nozzle Length: 0.352-Inch
Nozzle Diameter: 0.025-Inch
363-503 OE Tillotson Nozzle Check Valve fits HL-232B, HL-282B, HL-304A, HL-304E, HL-309A, HL-309E, HL-310A, HL-311A, HL-317A, HL-317E, HL-318A, HL-321A, HL321E, HL-334A, HL-334AA, HL-334AB, HL-334B, HL-339A, HL-384A, HL-384B, HL-385A