MALLORY 5250A

FORM 1038 (REV. F) 11/04
INSTALLATION INSTRUCTIONS
COMP PUMP® SERIES 250
ELECTRIC FUEL PUMP
PART NOS. 5250 AND 5250A
PARTS INCLUDED IN THIS KIT:
SPECIFICATIONS
1 COMP PUMP® Series 250 Electric Fuel Pump
3 Fittings, 3/4" - 16 x #8 AN Flare
3 O-rings, Nitrile 0.644ID x 0.087 thickness
Maximum recommended operating pressure: 20 PSI
(factory set at approximately 15 PSI)
Maximum dry suction lift: 3 feet. This is maximum distance
above the fuel level in the fuel tank that the fuel pump will
prime itself.
NOTE: DO NOT OPERATE THIS PUMP
WITHOUT FUEL EXCEPT FOR BRIEF
PERIODS WHILE PRIMING
Oil pressure switch rating: 15 AMP
Fuel pump over current protection: 15 AMP fuse
Fuel application: Part No. 5250, Gasoline; Part No. 5250A,
Alcohol / Methanol
GENERAL INFORMATION
The COMP PUMP® 250 Series Electric Fuel Pump is a high
volume fuel pump designed for serious racing applications.
The pump is factory set to approximately 15 PSI. In all
cases, this fuel pump must be used with a fuel pressure
regulator. We recommend the following:
Standard Regulator
Mallory 4 Port Regulator
Return Style Regulator
Mallory 5 Port Regulator
Part No. 4200
Part No. 4201
(gasoline)
(alcohol)
Part No. 4300M
Part No. 4301M
(gasoline)
(alcohol)
Be sure to install a suitable fuel filter (maximum 100 micron)
between the fuel tank and the fuel pump. Mallory COMP
FILTER® Series Part Nos. 3140 or 3500 are recommended.
This prevents debris from becoming wedged in the fuel
pump’s Gerotor and locking it. An additional filter(s)
(maximum 40 micron) should be installed just before
the carb(s).
This fuel system must have a fuel return line going to the fuel
tank. We recommend at minimum a #8 AN (1/2") line.
If you use a standard fuel pressure regulator, not a return
style, run the fuel return line from the fuel pump’s fuel return
port. Use the 3/4"-16 thread x #8 AN flare fitting provided to
connect your #8 AN line.
If you use a return style fuel pressure regulator, run a #10 AN
fuel return line from the fuel pressure regulator’s fuel return
port and install a 3/4"-16 thread plug and o-ring in the fuel
pump’s fuel return port. You can find a 3/4"-16 thread plug
at most hardware stores. Do not try to adjust the bypass
adjustment - pump damage may result.
MALLORY IGNITION
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MOUNTING PROCEDURE
FIGURE 1
Step 1
Mount the pump as close as possible to the fuel tank in a
well ventilated area with minimal exposure to road debris.
Avoid exposing the pump and fuel lines to moving parts
and hot surfaces, such as the exhaust system.
RED (+)
BLACK (–)
The pump should be mounted at tank level or below.
NOTE: Increasing distance between pump and tank will
decrease pump efficiency.
Step 2
Using the pump mounting bracket as a template, locate
mounting holes on a solid member, such as the vehicle
chassis. Drill clearance holes for 5/16" bolts. NOTE: To
ensure against a potential fire hazard from pump
flooding, mount the pump in a vertical position with
the motor on top.
FUEL OUTLET
3/4" - 16 (#8AN)
FUEL INLET
3/4" - 16 (#8AN)
See Figure 1.
Step 3
To prolong pump life and efficiency, a high volume fuel filter
such as the Mallory COMP FILTER® Series 500 Fuel Filter
(Part No. 3500) must be installed between the pump and
fuel tank. Connect #8 AN fuel lines as shown in Figure 2 for
Standard Regulator or #10 AN lines as shown in Figure 3
for Return (Bypass) Style Regulator.
Step 4
Be sure to install one of the Mallory High Volume Fuel
Pressure Regulators between the pump and carburetor.
For maximum efficiency, mount the pressure regulator
as close as possible to the carburetor. See instructions
packaged with the pressure regulator. Make sure all
fittings are tight so that air cannot enter the system.
NITRILE O-RING
NITRILE O-RING
FUEL RETURN 3/4" - 16
(MUST BE PLUGGED
WHEN USING A RETURN
[BYPASS] STYLE
REGULATOR
FIGURE 2
BYPASS ADJUSTMENT
NOTE: Bypass pressure above
20 psi will make the pump draw
more current and significantly
reduce pump life.
FUEL RETURN
FUEL
PUMP
FUEL
FILTER
REGULATOR
FUEL
TANK
CARB
(WITH STANDARD FUEL PRESSURE REGULATOR)
FUEL RETURN
PORT
FUEL
FILTER
FIGURE 3
(WITH REGULAR STYLE FUEL PRESSURE REGULATOR)
2
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MALLORY IGNITION
WIRING PROCEDURE
Wiring the pump to an oil pressure switch provides power
only when the ignition switch is on and the engine is
running. This prevents the pump from running if your
engine stalls. Use 12 gauge wire or larger and be sure to
disconnect the battery ground cable before wiring the
pump. Refer to Figure 4 when connecting the pump to
an oil pressure switch.
The pump may be wired directly to the ignition switch “ON”
terminal and grounded to the frame or battery. Refer to
Figure 5 when connecting the pump to the ignition switch
“ON” terminal.
FIGURE 4
RED (+)
FUSE (15 AMP)
IGNITION SWITCH
BLACK (-)
TO ACCESSORIES
FROM
VEHICLE
BATTERY
FUEL
PUMP
GROUND
COMMON
TO COIL (+)
NORMALLY
OPEN
NORMALLY
CLOSED
OIL PRESSURE SWITCH
VEHICLE
BATTERY
STARTER
GROUND
FIGURE 5
IGNITION SWITCH
TO ACCESSORIES
RED (+)
BLACK (-)
FUSE (15 AMP)
FROM
VEHICLE
BATTERY
TO COIL (+)
MALLORY IGNITION
FUEL
PUMP
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GROUND
3
MAINTENANCE –
PUMP DISASSEMBLY
Step 3
If your pump fails to produce adequate pressure or
volume, it may require cleaning. Follow the steps below to
disassemble and clean your Mallory Electric Fuel Pump.
Refer to Figure 6 while performing the following steps.
Place your hand beneath the gerotor and hold the pump in
an upright position. The gerotor should slide out of the
pump and into your hand.
Step 1
Remove the pump from the vehicle and clean pump exterior.
Place the pump on its side on a clean work surface. Scribe
or draw a line across the pump housing, port plate and fuel
chamber so that you can reassemble the pump correctly.
Step 2
Remove the two fuel chamber screws from the bottom of the
pump. Remove fuel chamber and port plate from the pump.
NOTE: Do not drop the gerotor from the pump cavity.
17
Step 4
To disassemble the fuel chamber, first remove the lock nut
and adjusting screw, then turn the fuel chamber over so that
the diaphragm spring falls into your hand. Remove the four
screws holding the diaphragm cap to the fuel chamber.
Remove the diaphragm cap, diaphragm, and damper spring
from the fuel chamber.
Step 5
Clean the gerotor and reinstall it in the pump housing.
Inspect the O-ring and gasket, and replace them if
necessary. Inspect the diaphragm for any small tears or
bubbles in the surface, and replace it if necessary. Inspect
the gerotor housing and port plate for wear. If the generator
has worn through the plating, return the pump to Mallory
for repair.
Step 6
Assemble the pump in the reverse order that you
disassembled it. Test bypass pressure. Adjust bypass
so that pump is producing between 13 and 20 psi.
16
24
15
23
1.
2.
*3.
*4.
5.
*6.
14
13
22
12
21
20
19
18
11
10
9
7
FIGURE 6
6
5
4
3
8
*7.
*8.
9.
*10.
11.
12.
*13.
*14.
*15.
16.
*17.
*18.
19.
20.
21.
22.
23.
24.
JAM NUT
ADJUSTING SCREW
PRESSURE ADJUSTMENT SPRING
CAP SCREW (4)
REGULATOR CAP
GASOLINE DIAPHRAGM
ALCOHOL/METHANOL DIAPHRAGM
FUEL CHAMBER SCREW
DAMPER SPRING
FUEL CHAMBER
FUEL CHAMBER GASKET
PORT PLATE
GEROTOR
GEROTOR BUSHING KEY
GEROTOR BUSHING
O-RING
GEROTOR HOUSING
SEAL
BRACKET VIBRATION GASKET
BRACKET
MOTOR HOUSING NUT (2)
MOTOR ADAPTER
SPRING WASHER
MOTOR ADAPTER SCREW (2)
MOTOR
*THESE PARTS ARE INCLUDED IN SEAL / DIAPHRAGM KITS
PART NO. 3171 FOR GASOLINE
PART NO. 3172 FOR ALCOHOL
2
1
IMPORTANT: Turn fuel chamber screws by hand until they
contact the chamber. Then torque to 24 inch/pounds
MALLORY IS A DIVISION OF THE MR. GASKET PERFORMANCE GROUP
10601 MEMPHIS AVE. #12, CLEVELAND, OH 44144
216.688.8300FAX 216.688.8306
4
FORM 1038
(REV. F) 11/04
Made in U.S.A.
Printed in U.S.A.
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