INSTALLATION INSTRUCTIONS
5-PORT RETURN STYLE
FUEL PRESSURE REGULATOR
SERIES 4300/4301
Mallory's 5-Port Return Style Fuel Pressure Regulator is
recommended for high volume applications (250-500
GPH). This regulator is available in two models:
• Series 4300, designed for gasoline applications
• Series 4301, designed for alcohol applications
For best efficiency, the regulator should be mounted as
close as possible to the carburetor.
Both regulators are adjustable from 5 to 18 PSI at a flow
rate of 500 GPH. To adjust pressure, loosen the jam nut
and turn the adjustment screw. Clockwise rotation
increases pressure.
NOTE: Adjusting fuel pressure higher than 7 PSI on
carbureted engines may cause carburetor flooding and
possible fire.
INLET FROM PUMP OR OUTLET TO CARB.
(#10 AN) CAN BE USED AS INLET FROM PUMP
OR OUTLET TO CARB. USE AS INLET FROM PUMP WHEN
RETURN TO FUEL TANK (#10 AN)
USE SAME SIZE RETURN LINE AS INLET LINE
USING HIGH VOLUME FUEL PUMPS (IN EXCESS OF 250 GPH)
MOUNTING SCREWS (2)
PRESSURE ADJUSTMENT SCREW
#8 AN (5-PLC'S) CAN BE USED AS
JAM NUT
VACUUM/BOOST COMPENSATING PORT
NOTE: A bypass at the fuel pump is not required for
this regulator. When using this regulator with Mallory
Series 5250 or 5500 fuel pumps, the fuel return port at
the pump should be plugged.
FORM 1077 (REV. A) 10/97
