Fuelab 55501 Fuel Pressure Regulator - Manual (Page 3)

105020521-1, Rev A Sheet 3 of 4
for gauge or fitting)
(Not Supplied)
-908 O-ring
Fitting Shown
(45 PSI Maximum)
-8AN Inlet Port
DO NOT LOOSEN
Part of Regulator.
Example -8AN Union
-908 O-ring Shown,
(Not Supplied)
Fitting Shown
Union
(Not Supplied)
Union Fitting Shown
Example -8AN
Installation
prior to Fitting
toward Regulator
Install with Cup
(Logo)
Front
Example -8AN
Gauge Port Plug
(can be substituted
1/8"-NPT Gauge Port
Sintered Bronze
Filter Shown (can be
Spring Guide Ball may appear to be Off-Center
Identification
Flat Washer
Jam Nut
Number
Screw
(3X) Bracket Screw
Adjustment
Lock Washer
(3X) Bracket
Unique Serial
for Both Sides)
Port (Same
-8AN Outlet
Ajustment Screw Centers this Part upon Installation.
other fitting)
substituted with
1/8"NPT Pressure
Reference Port
(Vented to Atmoshere
for Naturally Aspireted)
4. Apply light oil onto the threads of the Adjustment Screw. Thread the Adjustment Screw by hand until a slight
tension is felt, this position is the minimum pressure setting. Do not tighten screw any further. Pressure is to
be adjusted later in these instructions. Install the Flat Washer, then the Jam Nut. Tighten the Jam Nut hand
tight for later adjustment.
5. Install Bracket to regulator using supplied Bracket Screws and Bracket Lock Washers. Tighten Bracket Screws
between 25-40 in·oz of torque (snug, do not over tighten screws).
6. Install the fuel fittings (not supplied). The threads used on these Fuel Ports are not tapered or pipe threads.
Do not use Teflon

thread tape or thread sealant on these threads, as this can cause leakage or introduce
debris into the fuel system. Fittings to be used with these style of ports require use of the enclosed–906 O-
rings for proper sealing (reference diagrams, below). Use light oil to lubricate the O-rings just prior to
installation. Install the O-rings onto the fuel fitting first. Position the O-ring in the thread relief of the fitting as
shown in the diagram, below. Thread fitting into regulator and tighten between 5 and 15 ft·lbs of torque.
7. Use Teflon

tape or thread sealant on all 1/8”-NPT fittings to be used for the Gauge Port and Pressure
Reference Port (see diagrams, below). Install fittings or plug as required. If pressure reference port is not
plumbed, then install the Sintered Bronze Filter (supplied) and allow fitting to vent to atmosphere (do not plumb
or plug port). Use of Port Filter (only) does not require the use of Teflon

tape or thread sealant. For extra
level of safety, pressure reference port can be plumbed with float bowl vent, in case of rare diaphragm failure.
8. Install regulator assembly into vehicle, fastening the bracket to the vehicle. Attach fuel lines, Gauge Port line (if
external pressure gauge is used in application) and Pressure Reference Port line (if applicable). Boosted
applications (such as turbo or supercharger) will require a hose clamp on barbed fitting to prevent hose from
coming loose. Use of –3AN or –4AN fitting and line can also be used as a substitute to the barbed fitting.
9. Inspect fuel system for any contact of fuel lines or wires with other components that can cause chafing or
rubbing. Secure all components and fuel lines.
10. Connect the vehicle’s battery. If the float bowls of the carburetor are empty, then the fuel system can typically
be self-primed. If the float bowls are full, then fuel system may have trouble priming. One of the outlet fuel
lines can be used to purge system through fuel collector for initial priming. Start engine and fuel pump, while
monitoring fuel pressure. The pump will have to operate several seconds (60+) to prime and drive air out of the
fuel system. Fuel system pressure should read about 4-5 PSIG (use an external gauge for adjustment if a
permanent gauge is not used). Inspect vehicle for any leaks. Turn off fuel system and repair any leaks that
may be present before continuing.
11. When adjusting pressure, be sure that fuel pump and engine are operating to monitor pressure. Increase
pressure by rotating adjustment clockwise. Do not thread Adjustment Screw past jam nut within 1/8”. Over
tightening the adjustment screw can damage the regulator. For repeatable readings, engine should be
operating normally at idle. If the fuel system is not flowing (such as engine running) then adjustment will be
difficult, especially when trying to lower fuel pressure.
12. After final adjustment of fuel pressure, to desired level, tighten Jam Nut. Road test vehicle, and retest pressure
upon return to ensure accurate adjustment.