FORM 1529 (REV. A) 06/01 INSTALLATION INSTRUCTIONS ® COMPETITION RETURN STYLE FUEL PRESSURE REGULATOR PART NO. 4307M IMPORTANT: This regulator must use a fuel return line. The fuel return line runs between the fuel bypass port of the regulator and the fuel tank. Fuel pressures cannot be adjusted if the fuel return line is absent. PARTS INCLUDED IN THIS KIT 1 1 2 2 2 2 Fuel Pressure Regulator Bracket Bracket Mounting Screws 3/8" NPT Pipe Plugs AN-8 Fittings O-rings for Fittings SPECIFICATIONS: Port thread sizes: 3/8" NPT and AN-8 Adjustment range: 4-25 PSI Fuel Application: NOTE: Exact adjustment range depends on pump capacity and return line size. Gasoline and Alcohol/Methanol GENERAL INFORMATION Mallorys 4305M regulator regulates fuel pressure between high pressure fuel pumps and carburetors or throttle body fuel injection systems. The regulator is recommended for fuel pumps up to 200 gallons per hour. The 4307M regulator is a return style fuel pressure regulator. The excess fuel and fuel pressure is sent back to the fuel tank through the fuel return line. The fuel return line runs between the fuel bypass port of the regulator and the top of the fuel tank. The fuel tank must have provisions for a fuel return line. This regulator is equipped with a vacuum/boost compensation port (brass barb fitting) that can be used to momentarily decrease fuel pressure (vacuum compensation) at idle and part throttle, or increase fuel pressure under blower boost (boost compensation). While it is not necessary to connect a hose to the vacuum/boost compensation port, it may be beneficial in some cases. However, the small plug on the barb must be removed before use. You can mount the 4307M regulator at any angle. For maximum efficiency, mount it as close as possible to the carb or throttle body. DO NOT mount the regulator on or near exhaust manifolds. A bracket is provided for convenient mounting. ADJUSTMENT SCREW JAM NUT VACUUM/BOOST COMPENSATION PORT (3/16" O.D. BRASS BARB FITTING) REGULATOR CAP REGULATOR HOUSING OUTLETS TO CARBURETOR(S) (3 PLACES, 3/8" NPT) UNUSED PORTS MAY BE PLUGGED OR USED AS GAUGE PORTS BRACKET MOUNTING HOLES (2) INLET PORT FROM PUMP (AN-8) FUEL BYPASS PORT (AN-8) INSTALLING THE 4307M REGULATOR FUEL LINE SIZE (FROM PUMP TO REGULATOR) 1. Connect the fuel line and the return line. The return line must be attached to the bottom port on the regulator. The fuel line must be attached to the upper -8AN port on the regulator. Fittings must be purchased to adapt the fuel line and the return line to the regulator. The unused port(s) in the regulator can be plugged or used as gauge port(s). Minimum fuel line size is determined by the horsepower of the engine. Up to 350 HP: 5/16" or 4AN Up to 500 HP: 3/8" or 6AN Up to 700 HP: 1/2" or 8AN RETURN LINE SIZE 2. Turn the fuel pump on and check for leaks. If leaks are The minimum return line size is determined by the output found on the NPT (tapered) fittings, make sure the threads of the fuel pump. are covered properly with Teflon sealer. Up to 29 gal/hr (110 liter/hr): 1/4" or 3AN NOTE: If the fuel system will not prime properly, back Up to 45 gal/hr (170 liter/hr): 5/16" or 4AN the adjustment screw all the way out of the regulator Up to 90 gal/hr (340 liter/hr): 3/8" or 6AN until the system is primed. Then reinstall the adjustUp to 200 gal/hr (680 liter/hr): 1/2" or 8AN ment screw. 3. Set the fuel pressure. Loosen the jam nut on the top of the regulator and turn the brass adjustment screw to adjust the pressure. Clockwise increases pressure. MALLORY IS A DIVISION OF THE MR. GASKET PERFORMANCE GROUP 550 MALLORY WAY, CARSON CITY, NEVADA 89701 (775) 882-6600 FAX (775) 887- 4326 www.mrgasket.com FORM #1529 (REV. A) 06/01 Made in U.S.A. Printed in U.S.A.