Performance Requirements For Motor Driven Fuel Pumps - Piper PA-24 Comanche Service Manual

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PIPER COMANCHE SERVICE MANUAL
b. Inspect the eoupli"l (2). Use a
new
coupling if the old one appears deteriorated.
c. Reassemble the pump with a new motor psket (11) and a new motor if required. Tilhten the
motor nutS (14) JUSt snug. Be sure the couplinl (2) ellpJeS both the pump shaft and the motor shaft.
d. Run the pump
at
free delivery with test fluid. Usc an ammeter to measure motor current. Tip
motor to position it so that current is a minimum. Tilhten motor nutS to approximately 15 in. lbs, Test
pump as described in pancraph 5; the 24-hO\lr Nn-in may be omined.
4. Shaft Seal Replacement.
I.
Remove motor and associated
putS
u described
in
Section 3. Remove cover and associated
partS as dexribed in parqraph 2. Remove the eitht YanG (6) with care to avoid damqing them.
b. If
I
retainirIJ ring is found on "the pump shaft. tm10vuhis
with
suitable pliers and discard the
ring. Push the rotor assembly out of the pump. Remove the housiftt insert (4). notine its position. Using
I
.40 to .41 diametet. flat faced brass drift a"d arbor praa., pras the shaft seal (11) OUt of the houSlng
(3).
Use cue to avoid darnqina the bcari", surfaces.
Para
may now be wuhed in a mild solvent.
c.
Apply a thin uniform coating of "John Crane Plastic Lad Seal No.2" to the outSide diameter
of a new shah seal (12). (This seal may be a different type than the one which wu in the pump.) With the
covet end of the housing assembly on a flat surface.
IIJC
a
1$/16
diameter flat faced brass drift in an arbor
press to ptess the shaft sca.I (12) home in the housing UlCmbly (3).
d. Place the inscttion tool <Fipre 8·17) oYCt the end of the rotor assembly (5). Use: motor oil
to lubricate the end of the insertion tool and the
rbaftsa.l. Push and
twist the rotor assembly into the
housing uscmbly. Install the housing insert (4). Install the YUlG (6) radius end away from center. Install
the cover and associated
putS
per parapaph 2. Rcmewe inscttion tool. then install the motor and associated
partS pc::Section 3. Run in and tesc as described in puqraph 5.
S.
Performance Requirements For M.otor Driven Fuel Pumps.
a. Gencn1;
1.
Test fuel to be odorless minc:nl spiriu. specific gnvity .76, viscosity 1.0 cs
@
i8°F.
2. Pump shall be mounted with the motor horizontal.
3. Test stand to obtain a mirlimum length of 3/8 I.D. tubing to minimize restriction to fuel
flow.
4. 14 volts D.C. of the proper polarity shall be used throughout.
b. Requirements:
1. Pump to be run for 24 hours
at
14 volu with restricted cutlet.
2. Run pump until all air
is
removed from the system.
3. Restrict fue:! flow completely.
Model No. Pressure
Flow Amperes
480 Sl8-1 or 480 528
15 psi 4S JPh min. 5.5 mI.'<.
480533
20 psi 85gph min. 7.5 max.
4. Check for leakage at seal. cover lasket and through cutings.
5. Restrict flow as follows:
Model So.
Shutoff Pressure Amperes
480 S18-1 or 480528 25 psi max.
6.5 max.
480
S33 40 psi max. 10. max.
6. Observe for undue noise: dunng all phases of calibration. Excessive noise shall be cause for
rejection.
FUEL SYSTEM
ISSUED: 8/18/72
2Jl1