PLYMOUTH 1939-1941
Models P-7, P-8, P-9, P-10, P-11, P-12, T-125
Flange 1 1/2"
Throttle bore 1 9/16"
Main venturi 1 1/4" I.D.
Float Setting: Top of float 5/64" +- 1/64" below top of surface of carburetor body casting. You can fudge a bit higher due to the ethanol gasoline.
Set Idle Adjustment Screw - 1/2 to 1 1/4 turns open. For richer mixture, turn screw out. Do not idle engine below 300 RPM.
Main Metering Jet Calibrated to flow 254 to 258 cc per minute.
Main Vent Through diffuser (air bleed inside bowl) size .0315" (.80 mm) drill
Step Up Jet - #63 (.94mm) drill size.
Accelerating Pump - Stroke, summer setting (inner hole, short stroke), intermediate setting (center hole), winter setting (outer hole, long stroke). Due to the ethanol polluted gasoline, you may have to experiment with this.
Pump Discharge Jet Size - .0315 inch (.80 mm) drill. Due to the ethanol you may need to enlarge this by .001. Do this only if you have a lean condition.
Pump Adjustment - 3/8" plunger travel (center hole).
Carburetor Loading Up
Check float level. Wear on lip of float lever will raise float level. Before adjusting, be sure the float lever pin is firmly seated. Reset the float level by bending lip of float lever away from needle to raise level or bend lip toward needle to lower float level. Bend vertical lip of float only. DO NOT PUT PRESSURE ON NEEDLE VITON TIP.
Motor Stalls While Idling
Set throttle lever adjusting screw so motor runs approximately 300 rpm, then set idle adjustment screw to specifications. If these adjustments do not correct the trouble, remove idle orifice tube and plug assembly. Clean tube and passages with compressed air. At this point, if the carburetor has not been rebuilt in the last 12 months, then do so now.
Acceleration Not Satisfactory