Piper Arrow IV, Maintenance Manual

Page: 623 / 752

rubber bushings and insert the bushings into the retainers, rounded long edges first.
F. Place a new gasket on the magneto flange. Install the magneto carefully so the drive coupling lugs
mate with the slots of the drive bushings. Install and snug down the two sets of attaching screws.
Do not tighten at this time.
G. Breaker point opening may be checked by use of a suitable timing light. Tap the magneto case
with a non-marring hammer, counterclockwise (from the rear) to make certain the points are
closed. After the timing light indicates that the points are closed, tap the magneto lightly clockwise
until the points are open. Tighten the magneto attaching nuts.
H. Check timing by backing up crankshaft approximately 5 degrees and tapping gently forward until
the timing light indicates opening of breaker points. If timing is correct, the 20 degree mark
(midway between the 16 and 24 stamped on the crankshaft) will appear in the center of the
inspection hole. The crankshaft has punch marks in 2 degree increments with 16 and 24 at each
end. Tighten the magneto attachment nuts and replace the plug in the inspection hole on top of the
engine.
DISTRIBUTION.
INSPECTION OF HARNESS.
1. Check the lead assemblies for nicks, cuts, mutilated braiding, badly worn section or any other evidence
of physical damage. Inspect the spark plug sleeves for chafing or tears and damaged or stripped threads on
coupling nuts. Check the compression spring to see if it is broken or distorted. Inspect the grommet for tears.
Check all the mounting brackets and clamps to see that they are secure and not cracked.
2. Should a harness problem be suspected, integrity of the harness wiring may be checked using an
ohmmeter, buzzer, or other suitable device such as the Bendix/ECD High Tension Lead Tester Kits, P/N 11-
8950 or 11-8950-1; check each lead for continuity. If continuity does not exist, harness wire is broken and
must be replaced.
3. If an insulation failure is suspected, the condition of the insulation may be determined using the
Bendix 11-8950 and the 11-8950-1 High Tension Lead Tester Kits manufactured by the Electrical Components
Division, The Bendix Corporation, Sidney, New York.
4. Test Unit Preparation:
A. Install two “C” cells in the battery holder in accordance with correct position.
B. Check that red and black leads are open-circuited.
C. Depress PRESS-TO-TEST push-button switch.
D. Insure INDICATOR lamp flashes and GAP fires intermittently as long as PRESS-TO - T E S T
switch is depressed.
E. Interconnect both red and black high voltage leads and again depress PRESS-TO-TEST switch.
INDICATOR lamp only should flash. GAP does not fire.
F. Disconnect black and red leads.
5. Insulation Test:
A. Attach clip of red high voltage test lead to ignition harness lead terminal.
B. Attach black test lead clip to lead ferrule.
C. Depress PRESS-TO-TEST push-button switch.
D. Observe that INDICATOR lamp flashes and GAP fires intermittently as long as PRESS-TO-TEST
switch is held depressed.
E. Whenever INDICATOR lamp flashes and GAP fails to fire, lead under test is defective.
Effectivity 74-21-00
PA-28RT-201T Page 74-10
December 1, 1978
3D19
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL